»*^ "v-^ ^ *,;-^^ fi^ •»^' f?-v :setidacorus is shown. 4 .(;i;a('K k. coolkv on Soctions tiingoiitiai to the seed give, ot' coiii-st-, ii transvei'se section, or one oblique to the long axis of the cell Tiie I'onn of tlie cell in this view is, in genenil, hexii'>-onal, and such a section brings into view the surface of the cell walls, wher» the canals appear as disks or pits. (Compare PI. 2, fig. (i.) In Ornithogaluni, C4altonia, and Hosta (1*1. 1, (igs. .'i, 4, and 5), the walls of the endosperm cells are not greatly thickened, and the canals are more frefjucnt. They give a truer picture of the nature of the thickening, foi- they appear as processes grown from the wall into tlie lumen of the cell. The cells in Tnlijta, Allium, and others have very few canal connections between them, and the walls arc much thickened, so as to give the appearance of granular cell contents, iud)edd('il in a homogeneous mass of cellulose substance. No primary membrane appears, and the cell contents are evenly granular. PI. 1, figs. 6 and 7, are sketches of Tulipa seeds cut in the i-adial, and in the transverse direction, and viewed with different maguif^-ing powers. In Paris, the thickenings of the endosperm cells are slight and appear mainly at the auMes. PI. 1, fig. 8, illustrates the endosperm cells of Paris. PI. l.fl'^ 9, is a view of the cells when water has somewhat swelled the reserve cellulose. These cells differ from all the others mentioned, in that they contain starch. Lloydia (PI. 1, fig. 10) also contains starch in its endosperm cells, but in this latter case there is a probability that the processes of ripening were not entirely completed when the seeds were fixed in absolute alcohol. The condition of the testa seemed to show that they were lipe, and the seeds were falling from the pods, Init in Scilla sibirica, and in JSfarcissns pseudo-narci ssus, the starch found in the cells when the seeds were discharged from the pods, disappeared later. It is to be noticed that in general appearance of the w\alls four types of cells are to be found :-— 1. Cells which are prismatic in shape, and whose walls are considerably thickened, but with the original cell membrane clearly marked. In these, canals between con- tiguous cells are frequent. Ex. Polygonatum. 2. Cells where much reserve cellulose is present, and the shape of the original cell is somewhat obscured. Canals are less frequent here. Ex. Tulipa. 3. Cells where very little reserve cellulose is present, and this is laid down regu- larly on the walls. The canals between the cells are fre((uent. Ex. Galtonia. 4. Oells where the thickening has bt'cn slight, and this mainly af the corners. Ex. Paris. Reserve matters in the form of proteids and oil are everywhere associated with reserve cellulose in tiu' cells. This kind of reserve is in inverse proportion to the IJKSERVE CELLULOSE. 5 amount of reserve cellulose. When much reserve cellulose, and comparatively little other reserve, is present, the seeds are almost stone-hard when dry, and comparable with the ivory-nut, vvhei'e maiuiose-yielding reserve cellulose was first discovered. Only in exceptional cases is starch associated with these other reserve matters in the endosperm. This is true in Paris and Trillium, and, in Ijoth of these seeds, the reserve material on the walls is inconsiderable. Interesting resemblances between the seeds of related genera, are apparent, as well in the outward appearance as in the l)ehavior toward microchemical tests. Paris and Trillium cited above illustrate this. Of the twenty-eight genera studied these two are exceptions to the rule that in Liliaceae, Amaryllidaceae, and Tridaceae, reserve cellulose forms an important part of the nourishment stored in the seed for the young plant, and that starch is not present as a reserve matter. It should be mentioned that tlie association of starch as a reserve witli reserve ci'lhdose in seeds of Paris quadrifolift was (Irst pointed out by Reiss.' MicRocnEMicAL BEIIA.VIOU OF Reseuve Cellulose. Cellulose has been defined as a carbohydrate of the comjiosition (C,;Hi„0-)„, which is dissolved in cupranmioiiia. and is colored Idue with chloroiodide of zinc, with iodine, and with sulphuric acid. It has, however, been found necessary to distin- guish various modifications of cellulose occurring in the cell membranes of plants. Ordinary cellulose of cotton-fibers and cell membranes of young roots have a certain well-known action in the presence of iodine solutions, acids, caustic alkalies, coloring fluids, etc. Lignified membranes, suberized walls, etc., [)resent certain marked characteristics, which are none the less clear in the typical cases because gradations between classes appear. It seems possible to define the behavior of the reserve cellulose, as found in the seeds of Liliaceae, in the presence of microchemical tests, even though certain minor differences appear in the different seeds. Reserve materials of the cell wall have jjeen divided by Tschircii" into two classes, cellulose and vegetable mucilage. These, he says, are closely related, grada- tions between the two being found. Under cellulose he names two forms, the first that of Plioemx dactylifera and PhyteJephas macrocarpa, which he terms ''reserve cellu- ' Reiss, Ui'ber (lie natur iler reservei'dlnldso. Lnndw. -A. Tscliircli, Aiisrwamlti' iiHaiiziiiaiiiitniiiic, s. -fa:!. jalirluiihiT, IS, s. 74(1. 1S80. 6 GRACE E. COOLEY ON lose"^; the second that of Lupinus, Balsaiiiina, Tamarindus, Paeonia, and Sabadilhi, which lie terms " amyloid," as other botanists'- have done, the distinguishing mark being its behavior with iodine, in the presence of which reagent it turns blue, as starch does. Tschirch* considers that the reserve on the cell walls of the endospenn cc'lls of Phoenix and Phytelephas is pure cellulose. Reiss has shown that mannose-yielding reserve cellulose is present in Paris qua- drifoUa and Foeniculum officinale as well as Phoenix, Phytelephas, and a number of other seeds. On the other hand Paris and Foeniculum seeds are exceptional, in that reserve cellulose of the endosperm cells is not dissolved by cuprammonia.''' In the following experiments the material used, unless otherwise noted, is from dry, ripe seeds. Control tests were made with cotton-fibers, and 3'oung succulent shoots. Behavior toward Weak Mineral Acids. The action with hot, weak, mineral acids is perhaps the most important, as it is universal. In order to determine the behavior of reserve cellulose with sulphuric acid, sections of seeds of Polygonatwn multiflonim were boiled in one part concentrated sulphuric acid to five parts water. At the end of half a minute, the thickening on the walls had greatly swollen, and much had dissolved away, and after one minute the solution was complete ; the primary membrane with haemotoxylin took the strong coloring of pure cellulose, and with iodine remained colorless. With Asparagus officinalis, the ret^erve cellulose was entirely dissolved from the cells in one half minute's action of the hot acid. The same was the case with Allium cejja, Iris pseudacorus, and others. Sections of Scilla sibirica show swelling oi the cell walls with one minute's treatment with hot acid, and in two minutes the solution is effected. The reserve from cells of Tulipa seeds is also a little more slowly dissolved than from Polygonatum, and shows, during the process, the gradual separation of the cells from one another, by the solution of intercellular substance. When iodiue is applied, before the solu- tion is complete, the bounding walls of the separating cells are yellow, whereas the intercellular masses are brown. PI. 2, fif. 1, shows a, portion of the eudosperm of Polygonatum multijhtrum after one minute's boiling in sulphuric acid of the strength noted above. The reserve has disappeared from the cell walls, nnd the couteats of the cells are not entirely removed. In (ig. 2 the action of the acid has removed the cell contents as well. ' A. Tscliircli, iliiil, s. 171. 'Reiss, l.anihvirtlischat'tliche jalirbiicUer. 18. -' Schleiden, I'eber dtis iuiiylniil. Beitrilge zur botanik, 1844. Frank, .Ji.urii. f. prakt. iliciuie, ISiir,, s. 470, etc. RESERVE CELLULOSE. 7 PL 2, fig. 3, exhibits a view of some cells from TuVrpd fjes^itrnmn during the process of solution; the section was heated with iodine; the walls at a are colorless ; the musses of intercellular substance at h are brown. The action in weak hydrochloric acid is similar to that with sulphuric. Sections boiled in solutions of one part smoking acid to four of water lose the reserve of their walls in three minutes. Tulipa requires five minutes' boiling for the complete solution of the reserve from the walls. Sections from young stems of Primula, Begonia, Tropoeoluui, and cotton-fibers were subjected to the action of acids of the above strength'!, and serve to prove the different behavior of reserve cellulose towards these hot solutions of acids. Acetic acid does not affect the reserve cellulose. Cold, weak, mineral acids act very slowly. Sections of Polygonatum after four da3's in sulphuric acid, of the sti'ength which was used for tiie hot acid, were scarcely affected. At the end of twenty-four days in hydrochloric acid, one part acid to four of water, the walls of the endosperm cells in Polygonatum were much swollen, and, in some cases, the reserve was dissolved. Allvim cepa sections were not much affected after nine days in hydrochloric acid. PI. 2, figs. 4 and 5, illustrate the action of cold solutions of hydrochloric acid on Polygonatum. Concentrated sulphuric acid dissolves the reserve cellulose and the primary membrane very quickly. Alkalies. The endosperm of Polygonatum seeds is not visibly affected by strong or weak alkalies ; when sections of the seeds are boiled in a concentrated solution their walls swell slightly. In Colchicum seeds, the endosperm is not noticeably affected by weak or strong, cold or hot caustic potash. The cell walls in the seeds of Iris pseudacorus swell slightly with cold, weak caustic potash, more with strong solutions, and the action is still more marked when these solutions are hot. Sc'dla slblrlca has the walls of its endosperm cells strongly swollen in hot, strong caustic potash, though they swell only slightly in weak solutions. Sections of Paris quadrifolia, from seeds not quite ripe, were treated with hot, weak solutions of caustic potash and the thickenings were dissolved from the walls. The action of caustic soda upon reserve cellulose is similar to that of caustic potash. Solutions of Iodine. When the ripe endosperm of Polygonatum seeds is treated with iodine iu potassium iodide, the tliiclcened cell walls immediately take up the reagent in great quantities and become red-brown^ or, when the iodine is supplied in sufficient quantities, almost black. This power of absorbing great amounts of iodine with the brown reaction is characteristic of the reserve material of the walls of the endosperm cells in Liliaceae, Amaryllidaceae, and Iridaceae. In only three cases are exceptions found, and in these the cell walls remain colorless after treatment with the iodine, or g (il.'ACK K. COOI.KV OX well-ni"-h so. These j)liints are P((ris qi((i(lrifoIi((, 7'ri/Iiutii, ovntnm, and f'oJchicirni autumnale. The deep brown color, which, everywliere else in these endosperm cells, resnlts from the iodine liirnished, varies in shade to dull gray-hrown, as in seeds of Allium ursinum, l)ut clear red-brown is the general rule. If iodine is supijlied to the reserve cellulose in very small (luantities, particularly if alcoholic solutions are weakened with water, or a crystal of iodine is dissolved with water on the slide, the cell walls are not uniform in their behavior in the different seeds. Some are blue, or violet with tendencies to dirty brown; others are clear yellow or yellow-brown, with no tinge of violet or blue. Asjxtrdf/iis offichuilis, Hostu caerulea, Oni'dhogalum cmidatum, Narcissus ^^ncmc^o- narcissus, and Lilinm martagon are yellow or yellow-brown with no tendency to violet or blue; this is also the case with Allimn (-qxi, \^\i\\i^ A. nrslnum is pale violet to dirty brown. All the other seeds show in their reserve a trace of violet or blue, when weak, watery solutions of iodine ai'e applied. In Scilla siblrlca the color is often a clear beautiful blue, but it varies somewhat in different seeds. To summarize: we notice the following reactions with iodine solutions. 1. With strong potassium iodide solutions. a. (The exceptions.) Nearly colorless. Examples. Colchicum autumnale. Paris quadrifolia. Trillium ovatum. b. (The rule.) Deep brown-red to gray-brown. Exs. Polygonatum multiflorum. Iris pseudacorus. Lilinm martagon. Lloydia serotina. Galtonia candicans, etc. 2. With weak watery solutions from a crystal of iodine, or alcoholic solutions weak- ened with water. a. Yellow, or yellow-brown. Exs. Asparagus ollicinalis. Ornithogahun caudatum. Hosta caerulea. Narcissus pseudo-narcissus. Lilinm martagon. Allium cej)a. RESERVE CELLULOSE. 9 h. Violet, or blue, or violet-brown. Exs. Iris pseudacorus. Polygonatum multiflorum. Galtonia candicans. Allium ursinum. Tulipa gesiu'riana. Scilla sibirica. Nageli^ groups together under the name amyloid, the carbohydrates which are colored indigo-blue or clear violet by water solutions of iodine, and considers that where a dirty violet or bluish brown color occurs, the substance is a transition form from amyloid to mesamylin, by which term he characterizes the cellulose of the mem- branes of plants, which is not colored at all, or only from yellowish to yellowish brown, with iodine. This transition form he has found in the seeds of Iris giilden- stedtiana and in some species of Liliaceae and Amaryllidaceae. Amyloid, according to Reiss", is the constituent of the cell walls of plants, which is Ijlue with iodine and does not yield mannose. He finds mannose-jdelding reserve cellulose in seeds of All'mm cepa, Asparagus officinalis, Iris 2i>ie.iidacorus. In further characterizing the re.serve he says, " Gegen jodreagentien, natronlauge, uud Scluilze'sches gemisch verhjilt sie sich ahnlich Avie cellulose." The three seeds mentioned above do not react with iodine in the manner of ordinary cellulose, and Iris pseudacorus shows a tendency to the blue color which characterizes amyloid. Furthermore Reiss^ remarks, " Es war daher zu erwarten, dass das fiir die palmen erraittelte, audi fiir die gauze familie der Liliaceen gelten iniichte. Ich habe deshalb noch die samen von Asparagus officinalis verzuckert. Audi sie lieferten seminose. Nun ist Asparagus ein vertreter aus der unterfamilie der Smilaceen wahrend Allium der Lilieen angehort. Es berichtigt dies also um so mehr zu der annahme dass alien Liliaceen mit verdicktem endosperm die gleidie form der reserve- cellulose eigen ist." The natural conclusion from the above statements of Reiss would be that the reserve cellulose in all the seeds of Liliaceae would react the same in the presence of iodine. This is not found to be the case, as has been shown. On the other hand, I am inclined to think that here, in some cases, as Schulze^ has found else- where, there is a combination of substances, which would yield by hydrolysis differ- ' C. Nilgeli, Die cliemi.sche zusammensetzimg der starke- ^ Reiss, Landw. iabrb., 18, s. 7-57. korner, s. 209-210. 18.'').''). - Reiss, Landw. jahrbiiclier, 18, a. 763. *Sclmlze. Ber. der dent, cliem. gesellsctaft, 24, s. 2279. 10 GKACE E. roOLKY ON ent vsugars, sick' by side. Probably in all, the ground substance is the same, but it is difficult to suppose that the blue color of ScUIa Kibirica in the presence of iodine is produced by exactly the same substance which in other seeds is colorless or brown. Iodine and Sidplmrlc Acid. If we ti-eat the endosperm cells of Po!i/rjo7iatnm multifloriim with iodine, and then with sulphuric acid (one part water, with two parts sulphuric acid), the usual cellulose reaction is confined to the primary mem- brane and the reserve material is turned deep violet-blue, quite different from that of cellulose, while it swells and dissolves slowly. Tulipa shows no sign of blue color- ing with iodine and sulphuric acid, having instead a red-brown color, and it does not dissolve after half an hour. Asparagus does not give the violet-blue witli this treatment that Polygonatuni does. AUhmi cqxi, Iris pseudacorus, and others show the same reaction as Polygonatnm with iodine and sulphuric acid. Chloroiodide of Zinc. Chloroiodide of zinc acts upon the reserve cellulose in the same way as iodine in solutions of potassium iodide does. All the seeds studied show a brown color in the reserve of the endosperm walls except Paris and Colchi- cum, which react the same as with iodine. In the crest cells of the seed of Colchicum, which before the ripening of the seed are filled with starch, the cellulose reaction with chloroiodide of zinc takes place, and the blue color appears. Cuprammonia. With this reagent the reserve cellulose is entirely dissolved from the endosperm of all the seeds examined, with the exception of Paris (pmdrifolia} In Polygonatnm, the reserve cellulose was dissolved in ten minutes. Iris pseudacorus had the walls dissolved in twenty minutes. Tulipa, Scilla, Colchicum, Ornithogalum, Allium, and Narcissus range between these two in the time required to complete the solution of the walls of the endosperm. Anilin 8idphate and Phlorofjlucin loith Ilijdrochloric Acid. These reagents do not affect reserve cellulose. Phloroglucin and hot ffi/drochlori.c Acid." On the possibility of finding that reserve cellulose would give the rose-red reaction of tlie pentaglucoses, when treated with these reagents, sections of Polygonatuni, etc., were treated with an alcoholic solution of phloroglucin until they Avere impregnated with it, a little water was added and the sections wex-e then heated in hydrochloric acid, but in no case did the endosperm yield the rose color. Action of Boiling Water. When sections of Polygonatuni seeds are boiled in water for 6-9 hours, the structure of the cell wall is apparently unaltered. This is ' Relss, Landw. jahrbiiclier, 18, .s. 711. - Scliulze, Ber. der deut. cbem. gesellschaft, 24, s. 2279. RESERVE CELLULOSE. H true of the seeds of Colchicum, Scilla, and Tulipa. These react, too, in the same way toward iodine as before boiling. Iris 2^>^<^udacorus showed the walls of the endosperm very much swollen after eight hours' boiling. In sections of Paris seeds which were not quite ripe, the endosperm cells had tlieir thickened corners much swollen after eight hours' boiling. PI. 2, fig. 6, is a sketch of a few cells from tlic endosperm of Polygonatum, after eight hours' boiling; the contents of the cells have been boiled away, but the reserve is unaffected on the walls. The section was tangential to the seed, and the canals between the contiguous cells do not, on that account, always correspond; at a the surface of the cell wall sliows, with the ends of the canals appearing as pits. PL 2, fig. 7, represents the appearance of the cell walls of the endosperm of Ii-is pseudacorus after eight hours' boiling ; a distorted wall, h contents of the cell. This should be compared with PI. 1, fig. 2, which shows the cells of Iris 2)seudacorus treated with iodine. PI. 1, fig. 9, shows the swelling of the reserve material in the endosperm walls of Paris quadrifoUa, when allowed to lie in water some time. The seed was not quite ripe. PI. 1, fig. 8, is a sketch from the seed t)f Paris quadrifoUa treated with absolute alcohol. Action with Staining Fluids. Haematoxylin stains the reserve cellulose of Poly- gonatum seeds but slightly; the primary membrane, however, shows a beautiful deep violet color, which perfectly outlines the original cell walls. This is the case with seeds of Ornithogalum, Iris, Asparagus, etc. Tulipa takes the stain most vividly on the inner surface of the cells, for the reserve cellulose seems to be laid down as intercellular substance, as its method of solution under the action of sulphuric acid has already suggested (see PI. 2, fig. 3). Methyl violet also brings out distinctly'- the original wall of the cell as a well- defined line in the midst of the faintlv stained reserve material. Congo-red, if applied to the sections for only a short time, from fifteen minutes to half an hour, is easily washed out with water, excejit from the primary membrane. If the sections are left in congo-red from twenty-four to forty-eight hours and then care- fully washed, the reserve material is deeply stained. This color will hold perfectly for three months in seventy per cent alcohol. Summary. As a result of the foregoing investigations the following statements may be made with regard to the characteristics of reserve cellulose as seen in the Liliaceae. 12 GRACE E. COOLEY ON 1. Its easy solubility with hot, \V(3ak, miaei'al acids; the hemicellulose of Schulze. 2. Its deep brown color with iodine in potassium iodide, with the exception of Paris, Trillium, and Colchicum seeds. 3. Its behavior toward chloroiodide of zinc as toward iodine in potassium iodide solutions. 4. Its resistance to the action of boiling water; exception, /r^N pKeuddconis and unripe seeds of Paris. 5. The slight coloring with haematoxylin and methyl violet. 6. Intense coloring after long exposure to congo-red. 7. Violet-blue in many cases with sulphuric acid after iodine. In the above particulars, it is to be distinguished from ordinary cellulose. 8. The solubility in cuprammonia. 9. Behavior towards caustic alkalies. These last two characteristics it shares with ordinary cellulose, as in cotton-fibers, young shoots, etc. In general the reaction of the reserve cellulose in the presence of microchemical tests is fairly uniform, but thei^e are some exceptions. The most noticeable of these are : — 1. The reactions with weak, watery solutions of iodine, where the range is from blue and violet to bi'own, or the walls remain colorless. 2. The swelling of the walls of the endosperm cells of Iria pseudacorus and Pai'is with boiling water. 3. The exce2)tions to the action of sulphuric acid after iodine, as in Tulipa. 4. The different lengths of time required to dissolve the reserve cellulose in the presence of weak acids and cuprammonia. 5. The reserve of Paris is exceptional in the following particulars : — a. It swells considerably with water. h. It does not dissolve in cuprammonia. c. It is colorless with iodine, while Colchicum is faintlj' j-ellow. d. It occurs in connection with starch as a reserve substance. Trillium ovatum agrees with Paris in the three particulars investigated, and it is probable that it will be found insoluble in cuprammonia. These facts seem to point to the following conclusions, with regard to reserve cellulose in Liliaceae. RESERVE CELLULOSE. 13 1. That reserve cellulose is not identical with pure cellulose. 2. That it probably consists of a ground substance of identical chemical nature in all the seeds; Paris and Trillium may be excejjtions. 3. That the slight differences, noticed in the behavior of reserve cellulose, are due to the association of other substances with this ground substance in the same wall. Reserve Cellulose during Germinatiox. In order to study the history and final fate of reserve cellulose, seeds were planted and examined during the various phases of germination, until the young plants no longer depended upon the seed for nourishment. Sachs', as early as 1862, showed that reserve cellulose is a true reserve material, and is used up during the processes of germination. The seeds he studied were Allium cepa and Phoenix dacfylifera. Reiss- has jiroved the same to be true of the reserve cellulose of many other seeds, both dicotyledons and monocotyledons; and he has given particular attention to the mechanical process of solution. Furtheiinore, he has proved, macrochemically, that many seeds containing reserve cellulose, among them Iris i^seudacorus and Allium, cepa, yield mannose by hydrolysis. It is of interest to follow under the microscope, so far as the limited development of microchemistry will allow, the chemical result of solution. The following sketches of the history of the germination of the seeds of Polygo- natum multljiorum., Iris pseudacorus, etc., will illustrate the changes of the reserve cellulose during solution and absorption. Germination of Seeds of Polygonatum, m,idtiJiorum. Seeds of Polygonatum 7mdtijiorum, gathered Sept. 11, 1892, were planted April 24, 1894, after three days' soaking in water. After eight weeks, on June 19, they were found to have sprouted. The manner of germination is peculiar. The first effort of the plant is to establish itself finnly in the soil, and, to this end, it begins at once the construction of the rhizome which is so characteristic of the "enus. o The seed is spherical and hard, containing a large endosperm consisting of good-sized cells, whose walls are considerably thickened with reserve cellulose. In the cells are present oil and reserve protein matters, but no sugar and no starch. (Plate 1, fig. 1, illustrates these cells.) The embryo is small (PI. 3, fig. 1), and ' Sach.s, Keimungsgeschichte dfi' Allium cepa. etc. Bot. -Reis.s, Reservecellulo.se, Laiidw. jalirbiiolier, 18, .s. 71 1 . zeit., 1862-60. 14 GRACE E. COOLEY ON consists of a.rt of the cotyledon remains in the seed, and has enlarged to half the capacity of the seed, replacing the endosperm. Its petiole grew just enough to carry the hypocotyl and bud out of the seed and then enlarged. PI. 3, fig. 3, A, is a view of a young seedling in section, and B is the same enlarged. The section has been treated with iodine ; a, undissolved reserve mateiial of the endosperm to which iodine imparts the characteristic red-brown color; h, endo- sperm cells, from which reserve material has been dissolved and which are unstained with iodine; c, the cotyledon with its vascular system well formed; d, portion of the cot^dedon which carried the bud out of the seed; e, bud which has freed itself from the sheathing cotyledon;/", the stem already thickened and containing starch, i. e. the young rhizome ; g, root-hairs. Comparison with fig. 4, a younger stage of the seedling, will show the manner of extricating the bud from the seed. In this case the cotyledon is curiously lolled, and the sheath is apparent. In cotyledons from seedlings of this stage of development, there are short, well- formed spiral vessels in the vascular portions, and the system in the stem and root is well developed. The cells which lie in contact with the endosperm contain much oil — a little is to be found in cells in the neighborhood of the vascular portions, but none is to be found in the portions of the seedling which lie outside the seed. Starch-formers are to be found in the cells, near the bounding layer of the cotyle- don and near the vessels, and in these minute starch grains may often be detected. The presence of starch in the cotyledon is not constant; sometimes the cells contain consider- able quantities, but always in minute grains. The thickened stem and apical bud contain starch in grains, which seem permanent. In general the cells of the cotyledon in the seed are rather empty. No sugar is found in the seed, but in the cotyledon outside the seed a little is detected. In the endosperm, important changes have taken place. The outer masses next the seed-coats still take the characteristic red-brown color, and are unchanged. Adjacent to these, lie cells whose walls are no longer thickened, and remain colorless under the action of iodine; and farther in, in contact with the cotyledon, are mere shreds of pressed and distorted cell walls. 16 GRACE E. COOLEY ON In PI. 3, fig. 5, A, the condition of the endosperm cells which lie next the cotyledon is seen. Relics of former endosperm cells which have been exhausted of their contents, and pressed upon by the growing cotyledon e, appear at f; and at (j, are loose cells, which are empty but for the large oil drops. In B at a, are cells which have been distorted by pressure. The contents of the cells, as well as the reserve of the walls, are gradually withdrawn during the encroaching growth of the cotyledon. The solution of the reserve from the walls is slow and irreo-ular : sometimes the thickening remains at the corners after the rest of the walls are freed ; sometimes one wall is affected before the others ; and sometimes a large number of cells show a gradual melting away of the substance toward one direction. In the latter case the regular thin- ning of the walls produces a gradual shading of the color which iodine gives. In PL 3, fig. 7, an attempt has been made to represent, by light and shade, the appearance of the reserve cellulose, during its gradual withdrawal from the w\alls. PI. 3, fig. 6, illustrates the more irregular solution of the substance. While the solution is going on in the cells, the nucleus often lies in contact with the walls, and these cells, which already have given up their reserve protein matters, contain vacuoles and streaming protoplasm. Granular masses, filled with minute oil globules, cling to the dissolving walls. No starch is visible in the endosperm at any time and only a trace of sugar, if any, is to be detected. PI. 3, fig. 6, is a charactei'istic sketch, showing the oily, granular masses in contact with the walls, whicli are losing their reserve material j at n, is the nucleus. A section, which shows the outer layers of the cotyledon and several layers of the endosperm cells, exhibits the phases of solution and absorption. First, tlie thickly-filled endosperm cells give up their protein reserve matters and, probably, some oil ; then 'the cells, with the protoplasm in an active state and with large vacuoles, begin to lose the reserve masses of the walls ; and, lastly, tlie protoplasm and the oily matters, which seem to be derived, largely, from the cell walls tliemselves, are withdrawn, and, pressed upon by the cotyledon, the cells collapse. In the cotyledon, on the other hand, appear masses of oil in the outer layer of cells. None is found in the plant outside the seed, and only a little in other cells of the cotyledon. Instead, starch is formed in the starch-formers in the cotyledons in small, but varying amounts, and in large, and more permanent masses, in the bud and young rhizome. PI. 3, figs. 6 and 7, show the contents of the cells during the solution and withdrawal of the nourishment from the endosperm. In fig. 7, 1, are cells of the cotyledon, with abundant oil in the outer layer ; at n, the nucleus ; at (j, in the second layer appear the starch-builders. At 2 arc the walls of the collapsed cells pressed upon by the growing liESEHVE CELLirLOSE. I7 cotyledon. At 3 the cells are neiirly empty, and all tlie reserve cellulose is exiiausted. At 4 there is some reserve cellulose, which is gradually being removed; the cells still contain oil and protein matters. The outermost cells have been scarcely affecte, cotyledon ; e, root. The cotyledon is here somewhat coiled, as it lies in the endosperm. During growth the re.serve cellulose is dissolved away from the walls, leaving them almost isolated, l)ut active. The method of withdi'awing nourishment from the cells is much as in Ii-is, for the cotyledon does not enlarge so as to fill the seed as in Polygonatnm. The endosperm cells retain their protoplasmic contents and act as transfer agents from the cells beyond them. PI. 4, fig. G, shows a seed of Allinm cepa in section, when the resei-ve is almost entirely exhausted, a little only remaining on the walls of the cells in the neighborhood of the mieropyle, at c, in the (iguie. All the cells contain protoplasm and oil, .ind the gr(>atei' number have large vac- uoles, the granular protein mattei-s having been willidrawii. 'i'liis seems to be tlie first action of the cells. The ct)iled cotyledon contains a great deal of oil in all the cells, and no starch, in these respects differing from Polygonatum and Iris. Starch is found exceptionally in the cotyledon, when the growth has been stunted by accident, as when the root-tip was broken off, or occasionally, when the plant has well established itself and is assimilating vigorously before the reserve material is all exhausted. In other words: starch is some- times formed when the transfer of food to the young plant is cheeked. A little sugar appears in the endosperm and in tlu; cotyledon, but, as in the other seedlings, in very small amounts. PI. 4, (igs. 7 and 8, illustrate the method of solution of tlie reserve from the walls. Summari/. From the study of the germination of Polygonatum multifloriim, Tris, and Allium, we gain a general idea of the history of the reserve cellulose during ger- mination. 1. The method of solution, in all the seeds, [)oints to the tact, elsewhere proved, that the reserve cellulose has been laid down on the original cell walls as a secondary product, not as a constituent part of the original wall. 2. The solution goes on, while the proto[)lasm of the cell is in an active state. 3. In all cases where the solution is i^oinii' on, minute u:lobules of oil are found in close contact with the wall. These are of a kind not colored, or only slightly so, with iodine. 4. Oil is transferred to the cotyledon, and is found either in tlu» outer layers of cells, as in Polygonatum and J lis, or throughout, the mass of the cells, as in Allium. 5. Starch is only an end product of this activity and does not appear at all in the cotyledon of Allium unless the removal of material is arrested. 6. . Sugar can only be detected in minutes (piantities during these jirocesses. RESERVE CELLULOSE. 21 7. In all Mie seeds the cotyledon is tlie ;iu;i'iit of absorption and transfer. In Allium and Iris, a large number of the endosp^'rui cells are also active in transferring the reserve material, and in these cases, all the cells contain protoplasm and oil until the reserve cellulose is exhausted, and then, only, become empty and collapse. Development of Reserve Cellulose in the Seed. To understand rightly the nature of the reserve cellulose, regard must be had to the phenomena connected witli its appearance during the formation of the seed. Accordingly, fruit-pods of Iris sibirlca, and berries of Polygonatinn 7nuUiflo)'U7n, have been gathered during the formation of the seed, and all the different stages of develop- ment have been followed under the microscope. These observations have been com- bined with a less detailed study of a nundier of other seeds, during the processes of ripening, so that a somewhat full history of the origin and growth of reserve cellulose in the Liliaceae, and its allies, lies before us. Growth of (he Seed of Iris sihirlcn. Iris sibirlca, on June 20, 1804, four weeks after flowering, had well-developed fruit- pods, with young seeds, which, in many cases, contained well-formed embryos, and endosperm, in which cell division had ceased and the walls were formed. The young seeds are flat and green, the immature testa containing much chloro- phyll. Next these loose cells of the outer integument lies a, layer of firm, small cells, with no intercellular spaces. Each of the cells in the layer contains a large greenish yellow, oily globule, which half fills it. Two layers of spongy, almost empty, cells lie between these and the endosperm. The endosperm cells, when cell-division has ceased, show, in sections made in the plane of the long diameter of the seed, a radical arrangemejit. The small, though perfectly formed, embryo lies at the micropylar end, and opposite, as the ovule is anatropous, the firm irregular cells of the chalaza appear, to which leads the bundle of spiral vessels, which furnishes the path of food communication with the mother plant. PI. 5, fig. 1, presents a view of a section of the seed, taken in the plane of its long diameter at this stage of development: a. endosperm; h, end^ryo ; c, layer of cells containing oil drops ; d, chalaza, in whose cells is a little starch ; e, chlorophyll, containing cells of the integument. Though the cells of the endosperm are all 22 GRACE E. COOLEY ON formefl, <1h' walls arc very tliiii, and the jirotoplasm streams in delicate threads from the larye nuclei to the walls. The protoplasm, in the masses, which are in contact with the walls, is very granular and contains many tiny oil globules. The cells in general contain large quantities of oil and much sugar. PI. 5, fig. 2, is a sketch of . Portion of the endosperm of the .seed of Pidi/i/Diudiiin »(H//(riyra/«, eleven weeks after planting. Tlie irregular solution of the reserve of the walls is shown ; o, oil ; n, nucleus. Small globules of oil, in contact with the wall, are shown. X 350. Fig. 7. Portion of the seed of Pidi/i/onidnm iiiidUflundn fVJ:ht weeks after planting. 1. Cells of the cotyledon, contain- ing much oil in the outer row ; a. nucleus; n, inner cells, containing starch formers with starch. 2. Mass of collapsed cells. 3. Cells from which the reserve is dissolved. 4. Cells which show the gradual and quite uniform solution of tlie reserve ; 6, gramdar aiul oily, reserve contents ; o, oil. x 3.50. PLATL 4. Fig. 1. Young seedUng of Iria pucudarnrns tour weeks after sowing the seed. A, a, seed with testa ; ft. petiole ; r. luuMiy tip of petiole, which lirst appears above the ground ; d. sheathing portion of the petiole; e, stem; /, root ; ;/, first leaf above the soil. Natural size. B, section of the seed from the same seedling; a, cotyledon filled with starch; 6, endosperm with thickened walls; c. endosperm cells, from which the reserve is dissolved. Natural size. Fig. 2. Section of seedling of Iris pxciidiirorufi. still in the soil (with ioiline) ; a. endosperm ; ft, cotyledon ; <■, petiole of the same; d, horny tip; e. .sheathing portion ; /', bud ; ;/, liyp ic.ityl. Stareli is seen in the sheathing part of the petiole in the bud, and in the hypocotyl. Natur.al size. RESERVE CELLULOSE. 29 Fig. 3. Section of the seed of Iris pseudacorus when the pliiiit was three inches liigh ; a, cotyledon with much starch in the cells ; b, vascular portion ; c, cells from which the reserve is dissolved, they still contain protoplasm ; on the edges of the seed the walls are still thickened ; at d, the cells are displaced by cutting. Enlarged. Fig. 4. Isolated cell from the endosperm, examined in water ; a, nucleus ; b, oil drop, smaller ones and minute globules near the walls ; the arrows indicate the direction of the streaming of the protoplasm, x 3-50. Fig. 5. Seedlings of Allium cepa at different stages ; n, seed ; b, cotyledon ; e, root; B, section of the seed of II ; most of the food has been absorbed by the coiled tip of the cotyledon. Ill has freed itself from the seed on emerging from the ground ; the cotyledon tip is not gi'een, and is about to wither away. Natural size. Fig. 6. Section of seed of Allium cepa as in fig. 5, II; a, cotyledon ; b, endosperm, with reserve dissolved from the walls ; at c, the walls are still thickened. Enlarged. Fig. 7. A few cells from the seed of Allium cepa showing the method of solution ; a, undissolved reserve cellulo.se ; ft, spaces between the cells, from which the reserve is dissolved. Not drawn to scale. Fig. 8. Cells of Allium cepa near the edge of the seed ; solution of the reserve is going on in tlie cells at a. x 350. PLATE 5. rig. 1. Section of the young seed of Iris sibirira, in the plane of the long axis; a, endosperm; b, embryo; e, layer of close-set cells, containing oil drops ; d, chalaza, with a little starch in the cells ; e, cells of the outer integiiment, containing chlorophyll, x 350. Fig. 2. Endosperm cells of Iris sibirica in the unripe seed ; the oil has been removed by absolute alcohol, x 350. Fig. 3. Cells from the close-set layer, in the integument ; each contains a greenisli yellow oil globule, x 350. Fig. 4. Cells of endosperm of Iris sibirica, at the stage when the tliickening of tlie walls is beginning. The section is in absolute alcohol ; n. nucleus ; o, oil. Fig. 6. Cells from the outer layers of the endosperm of Iris sibirica, when only a slight amount of reserve cellulose is present in the seed ; n, nucleus ; I, crescent shaped bodies, which, with the proteids about the nucleus, color red-brown with iodine, x 350. Fig. 6. Cells from tlie same section as in fig. 4, after water has been applied, x 350. Fig. 7. Later stage in the swelling of the reserve cellulose in a seed from the sam3 as in fi j;s. 4 and 0. x 350. Fig. 8. A few cells from the endosperm of Iris sibirica when treated with chloroiodide zinc ; a, swollen masses of reserve cellulose ; b, granular matters aggregated by the swelling of certain layers of the cell wall ; c, protoplasmic membrane still extending to the original wall, x 350. Fig. Si. Cells from section of Iris sibirica seed which was cut transverse to tlie section in fig. 8. Treatment the same as above, x 350. Fig. 10. Cells from the close set layer of llie integument, from seeds of Iris sibiric{i. two weeks later than in fig. 3. x 3.5(1. Fig. 11. Cells from endosperm of Iris siliirica after the thickening of the walls lia,cl begun, x 350. PLATE 0. Fig. 1. Early stage of the endosperm cells of the seed of PDh/i/onatiim ;/inff(//")'H»), before the walls are formed. Witli absolute alcohol and haematoxylin. x 350. Fig. 2. Cells of endosperm of Pulyrjonatum muliifl-orum, soon after formation ; n, nucleus with several nucleoli, x 350. Fig. 3. Cell of endosperm of Pidi/f/unatum multifiorum, before the thickening of the wall. The oil has been aggi'egated by treatment with chloral hydrate ; o, oil ; n, nucleus, x 350. Fig. 4. Cells of the endosperm near the chalaza in a seed of Puliiijonatum, uiulUflorum, before any reserve cellulose lias api^eared in the endosperm; n, nucleus, with starch-grains in the starch- formers, in the neighborhood; with absolute alcohol and iodine, x 350. Fig. 5. Cells from the seed of Pnli/nonatiiin uiiillijh>riiiii. wiuii llie reserve cellulose first appears in the cell; », nucleus ; a, reserve cellulose, x 350. Fig. G. Cells from the same endosperm as in fig. 5, where tlic tliickening lias proceeded farther. The two sketches are from sections treated with ioilhie; ((.nucleus, x 3.5(1. Fig. 7. Cells from near the center of the endo.sperm of Calaidhas nicalis, in the later stages of ripening. Only a few cells remain with unthickened walls; with iodine; n, nucleus; s. starch. At B the surface of some of the cell walls is shown with points of less thickening at fi. x 350. Fig. 8. Section of nearly ripe seed of Ctilchicum autuinnale : a, embryo, containing starch; e. endosperm; c, crest of the seed containing much starch. Enlarged. , Fig. 9. Endosperm cells of Colchicniii antuumaU: when the .seed is nearly ripe; with iodine; small intercellular spaces occur at the corners, x 350. Fig. 10. Cell from the crest of the seed of C'olc/iirnm aatuuiimb: when nearly ripe; large starch grains are present The section was treated with iodine, x 350. PUBLICATIONS OF THE BOSTON SOCIETY OF NATURAL HISTORY. FROCEEDINaS. 8vo. Vol. XXVI iK.iv issniii'r, f.l.OO to inumbers; $4.(10 to the public. Vols. III. VII, VIII. XIV-XXV per Voliiiiie, boniiil ill clolli, .'ji;!.;")!! to uR'iiibers; .'3i-t..")0 to the piiblif. Other voliimos s.Mi)T,()iiK;Ai, Oohrrsi-ondknck, ok Pk. T. W. Hauuis. Edited by S. H. Scudder. 875 pp. Portrait and 4 plates. lHf.lt. Ch)tli, $i.r,0. II. Tun SiMDKUs OK TiiK Unitkd STATES. 15y N. M. ItK>?TZ. Edited by Edward Burges.s, with Notes by James II Eiiiertoii. 171 pp., 21 plates. 1875. Cloth, p. ,50; Paper, .p.OO. III. TiiK (iKouxiY OK Massaoihisktts. By W. O. Cuoshy. 2.S(; pp. Colored map and 5 plates. 1880. Cloth, .33.50; I'apis. Illustrations of Carbonifenuis Arachnida. The insects of the Triassic beds at I<'airplay, Col. 181)0, 72 pp., 12 plates. $3.25. Sli;iler, N. S. Recent changes of level on the co.ast of Maine. 1874,20 pp. 40 cts. Antiquity of caverns and cavei'n life of the Ohio valley. 1875, 0 pp., 1 plate. 40 cts. Classiii(;ation of lavas. 1880, 15 pp. .50 ets. Tha.xter, Uoland. The Entomoiihthoreae of the United States. 1888, (18 pp., 8 Jilates. $3.50. Trelease. William. North American Geraniaeeae. 188,s. 34 pp., 4 plates. $1.25. Address SECKK.r.Mn Boston Society Natmkal IIistoiiv. ISoston, Mass., U.S.A. MEMOIRS OF THE BOSTON SOCIETY OF NATURAL HISTORY; VOLUME 5, NUiMBER 2. NOTES ON THE DISSECTION AND BRAIN OF THE CHIMPANZEE '' GUMBO." By THOMAS DWI6HT. BOSTON: published by the society. October, 1895. K"^V 1 . im Notes on the Dissection and Brain of the Chimpanzee " (iumbo '" ( Troylodytes nlger) . By Thomas Dwight. Read May 15, 1895. " Gumbo" was a very fine male chimpanzee who at one time was kept in the Royal zoological gardens at Lisbon. He was leased to a museum at Boston, where he died in the autumn of 1894 of general tuberculosis. He had probably reached very nearly his full size, though the last of his second teeth had not taken their permanent position, and some of the epiphyses were distinct. Before his sickness he was remarkably muscular. He is said to have been very intelligent, but was not trained to rival " Sally." His temper was violent. I regret that I never saw him alive. Even after death he did not come into my hands until after the autopsy. This was performed more than twenty-four hours after death. The progress of putrefaction combined with the effects of tubercu- losis had made the condition of the thoracic and abdominal cavities truly frightful. The viscera and skin were practically worthless. The brain, happily, was perfectly healthy. The body was then sent t(j the Harvard medical school and dismembered as soon as possible. There was a great deal of very black hair about the face. Indeed, the hair was black, or nearly so, everywhere. There were bare spots, almost callosities, over the tuberosities of the ischia. The height, measured after the removal of the brain, from vertex to heel, the leg being straightened as much as possible, was about 131 cm. This must be regarded as only approximate. The length of the hand from the fold at the wrist to the end of the middle finger was 24.4 cm. on the right. The left was 1 mm. longer. The length of the foot to the end of the third toe was 24.7 cm. on the right, and 2 mm. less on the left. The great toe resembled strikingly a human thumb, and the lines on the sole of the foot were much more like those of the human hand than were those of " Sally " as shown in Mr. Beddard's^ figures. The lines of the hands and feet are well shown in the reproductions of the photographs (pi. 7). The ear is admittedly very variable in the chimpanzee. Those of " Gumbo," like those of the T. auhryi' and of "Mr. Crowley," the New York chimpanzee, are more 'Trans, zool. ,icutaneons nerve. It divides into two parts. One, tendinous, is inserted into the inner part of the front of the humerus from a little above the middle to the junction of the second and lower thirds or even further. The other part, chiefly muscular, is inserted into the internal muscular septum in the lower third of the arm and b}- an expansion into the fascia of the arm, being fused with the termination of the dorso-epitrochlearis. Triceps. The only point to be noted is that, besides its usual insertion, it expands into the fascia of the back of the fore-arm. Pronator radii teres has two heads with the human relations to nerve and artery {vide flexor carjyi radialis). Palmaris lomjus is inserted more to the radial side than in man. Flexor carpi radialis. Besides the usual origin it arises from the oblique line of the radius by a fibrous layer which gives origin to the fibers of the pronator teres ; below the oblique line it arises from the anterior border of the radius to within two inches of the lower end. It is inserted into the base of the second metacarpal. This origin resembles that seen in the gorilla but not in " Sally " nor in Hepburn's chimpanzee. The insertion is the same as that seen in " Sally." In both respects it agrees with Gratiolet and Alix's Troglodytes atibryi. Flexor carjn nlnaris. A tendinous slip arises high up from the deep aspect of its ulnar aponeurosis of origin. From this a series of short muscular fibers run obli(iuely downward and outward to another parallel tendon which, lying superficial to the flexor tendons of the finsjers, is inserted into the annular ligament to the radial side of the pisifoi'in, which bone receives the main tendon. The ulnar nerve comes to the surface between the two tendons. (The deep tendon gives origin to some fibers of the flexor sublimis digitorum.) This may be called either a double in-sertion of this muscle, or we may say tliat there is an extra palmaris longus. Something resembling this seems to have been seen in gorilla by Duvernoy. Flexor sublimis digitorum arises (1) from tlie common condyloid muscular mass and septa within it, (2) from the coronoid, and (3) from the oblique line of the radius. This head is attached also along the anterior Ijorder to within about 2 1-2 inches of the lower end. The tendon of the little finger arises from the superficial mass on the ulnar side. The tendon of the annularis arises from the superficial mass more anteriorly. It receives an insignificant reinforcement from the top of the oblique line of the radius. The tendon of the middle finger receives its fibers from the coronoid head and from practically the whole radial origin, whence the fibers run into the edge and THE ANATOMY OF THE CHIMPANZEE. 37 anterior surface of the tendon. This is much tlie largest tendon. That of the index arises as a small muscular belly from the coronoid, soon becomes tendinous, and sends a small muscular bundle to the division for the third finger. It then gives off a sei'ies of short oblique fibers, which run to another parallel tendon which is the terminal one. It passes obliquely under the others just above the wrist. The three inner tendons pass under the annular ligament in the same plane, that for the little finger being a shade behind. Expressed differently, the condyloid head supplies the fourth and fiftli fingers (the latter receiving a trifling bundle from the radius). The coronoid head goes to the middle finger and index. The radial head goes to the middle finger. N. B. A connecting link with the flexor profundus arises as a muscle, perhaps 1-2 inch broad and from 5 to 6 inches long, from the coronoid portion. Its tendon becomes the deep tendon of the index and receives on its radial side tlie fibers of the radial portion of the muscle next described. Flexor profundus digitorum is very clearly divided into a smaller radial and a larger ulnar part. The former arises from the front of the radius and a little of the inter- osseous membrane; all its fibers go into the connecting link just described, which is the tendon of the index. The ulnar portion (separated from the radial by the anterior interosseous vessels and nerves) divides into three tendons. That for the minimus comes from a muscular ))elly that is distinct nearly half way up the fore-arm. The other two are much more closely connected. The ulnar portion also gives some muscular fibers to the index tendon. Flexor longiis jiolUcis has no existence whatever as a muscle. A minute tendon first appears a little above the annular ligament as a thickening of the delicate sheath of the radial part of the flexor profimdus. As it descends it grows stronger, becoming a well-defined little tendon, perhaps 1.5 mm. broad, going to the second phalanx of the thumb. This has been repeatedly seen in the chimpanzee, but usually the tendon comes directly from the muscle. There can be, I think, no (question that in this flexor groui) the anthropoids exhibit much individual variation. The accurate comparison ot the different descriptions is more wearisome than profitable, owing to the complication of the structure. The accounts all dift'er more or less. The connecting slip from the superficial flexor to the deep one is not normal in the chimpanzee, but occurs as an anomaly as it does in man. In " Sally " such a slip was found going to the deep tendon of the ring finger. Lumbricales are four in number. The first arises from the radial side of the tendon of the index; the second from the other side of this tendon and the radial side of the tendon of the medius. The third springs from the neighboring sides of the tendons 38 THOMAS DWICTIT OK of the medius and annularis; the fourth from the uhiar side of the latter. The accounts of these muscles in various chimpanzees show trifling differences in most cases. Pronator quadratus. Similar on both sides. It is in two layers which are only partly separable. The more superficial begins as a tendon at the top of the ulnar origin and expands as it passes downward and outward across the muscle. It gradually becomes muscular, and having reached the outside of the radius, runs downward (hidden by the flexor carpi radialis) to the ridge of the trapezium. It is about 7 mm. broad at the end. The deeper, more transverse part of the muscle runs somewhat slanting downward to the radius. A few fibers near the radial side go to the front of the capsule of the wrist. This is an anomaly very rarely observed in man. I cannot find any record of it in the chimpanzee. Macalister observed it in a Bengal tiger, though it is not normal in the Felidae. It seems to show that animals of diverse groups have a tendency to similar variations which are not determined by heredity.' I am not aware that the pronator quadratus as above described is normal in any mammal. Palmar muscles of the thumb. Ahrhictor hrerls runs from the annular ligament and sesamoid bone to the base of the first phalanx. Its tendon, reinforced by tlie flexor brevis, passes into an expansion with a tendinous insertion into the second phalanx. Opponens poU'icts from the annular ligament more or less fused with the flexor brevis. Adductor pollicis transversus from the fibrous aponeurosis which is stretched over the fourth metacarpal. It arises directly from the distal part of the third metacarpal. There is a slight interspace allowing it to be divided into a proximal and a distal part ; both in the same plane. Adductor obllquus from the base of the third metacarpal to the usual insertion and by a very small tendon to the second phalanx. Flexor brevis has no inner head. Hepbuin found a rudimentary one. Palmar muscles of the little finger. Practically as in man. The interossei are discussed after the other muscles of the fore-arm. Extensor communis. Not remarkable. Portion for index easily separable in the lower third of the arm. The tendon for the little finger sends fibers to the fourth. Wilder found no tendon to the little finger. Extensor minimi digit!. This supplies both the fourth and fifth fingers (as Hep- burn describes for the orang-outang and Beddard for '' Sally " ). The action of the extensor tendons seems to be nearly limited to the first phalanges. ' The sicnificance of annmalips. Ainer. ii.it., Feb.. ISO'). ■ Vvne. Host. .sue. iiat. hist., 1801. THE ANATOMY OF THE CHIMPANZEE. 39 Abductor pollicis longus to trapezium and sesamoid bone. Exten>ior nrlml iiitevnod'il nollic'o^ is so fused with the preceding as to su'j-o-est one muscle with two tendons; it is inserted into tlie base of the first metacarpal on the radial side (better called extensor pollicis brevis). Extensor secundi internodil poll'icU, vel extensor jJoUieis longus, I'uns from the lower part of the ulna and interosseous membrane into a fibrous expansion over the back of the thumb, and is inserted into the second phalanx. Extensor propr'ius hidicis is a small muscle going to the index only; in Hepburn's chimpanzee it sent a slip to the ring finger. Interossei manus. There are four dorsal, practically the same as in man. There are seven palmar; namely, two for the index, the middle and ring fingers, respectively, and one for the little finger. The smallest of these is the first. It arises from the radial side of the metacarpal bone of the index internal to the belly of the dorsal. The second is a large one on the ulnar side of the index. The third and fourth lie on the metacarpal of the middle finger, touching each other and arising in part from a fibrous septum between them. The third receives also a few fibers from the base of the second metacarpal. The fifth and sixth arise (excepting for the last detail) in a similar manner from the fourth metacarpal. The seventh arises from the radial side of tlie fifth metacarpal and from the hook of the unciform. There is (with one exception) an important difference between the insertion of the dorsal and palmar interossei. The dorsal are attached to the sides of the bases of the first phalanges, still the chief action is to flex them ; lateral movement is not great. The palmar ones end in well-defined tendons which run along the sides of the first phalanges and end in the fibrous expansion over their dorsal aspects. Their chief action is to flex the first phalanges and extend the second and third. The excep- tion alluded to is the first palmar which has a very small tendon more or less fused with that of the first dorsal. The chimpanzee has been described as having six palmar interossei, my little first one not having, I believe, been hitherto observed. I have called it a palmar interosseous because it seems to me a distinct uiuscle; still its mode of termination gives support to those who would call it a part of the first dorsal. For the others not found in man I cannot admit this interpretation. They are all in the same plane and have a similar insertion. Compare Hepburn on anthropoids, Cunningham on Thylacine (Journ. aiiat. physiol., vol. 12), and Champneys on chimpanzee (ibid., vol. 6). 40 THOMAS mvionT ox Lower Extremity. Gluteus maximum. Origin as usually described, including a thick portion from the tuberosity of the ischium. It is inserted into the fascia lata, into the gluteal I'idge and back of the femur quite down to the external condjde and joining the tendon of the biceps at the knee. This is a somewhat lower insertion than is usually described. No separate tensor vaginae femor'is. A small one is usually found. Scansorius arises from the anterior border of the ilium and is inserted in common with the gluteus minimus. Pyrlformls inseparably connected with gluteus medius. Gemellus siqjerior, broad; gemellus inferior, small. Quadratus femoris. A small muscle, arising from the front of the tuberosity of the ischium, runs to the posterior intertrochanteric line, reaching lesser trochanter. (T do not find Hepburn's vertical part.) Biceps femoris. Has the two parts distinct. Tlie ischial portion goes to the head of the libula, sends an expansion to the front of the external tuberosity of the tibia, and is connected with the sural fascia. The femoral portion runs to tlie head of the fibula and to the fascia of the calf. (c^uadriceps extensor, differing from that of " Sally,'' is easily separable into four parts. The vastus internus overlaps the cruraeus from which it is much more distinct than is the vastus externus. Rectus has bt)th heads. Gracilis seems three or four times as strong as sartorius ; they botli end in broad expansions which are inserted more than one third and one half way down the leg, respectively. Adductor group is very puzzling. Pectineus is small, but distinct. Adductor magnus arises from the tuberosity of the ischium and runs down as a thick round belly to the adductor tubercle. This seems to be the whole mus- cle, being perfectly distinct. The femoral artery passes back between it and the muscle now to be mentioned, to become the popliteal. This is an extremely thick and strong muscuhir mass arising from the front of the pubes and from the pubic arch and running to the linea aspera. Separate muscles are not to be made out. 1 recognized no adductor longus nor hrevis. It represents all the adductors of human anatomy except the vertical portion of the adductor magnus. This division of the adductor magnus into two parts is noimal in the chimpanzee, but the fusion of one TllK AXATOMV OF TIIP] (illMPANZKE. 41 jjart vvitli the other adductors is peculiar. Wilder found the pectlnem and three adductors 25i"esent Init more intiniatel_y connected than in man. The anterior muscles of the leg, \\m peronel, those of the calf, present nothing note- worthy. The plantaris is present and distinct, going partly to the tendo Achillis and partly to the fascia at the inner side of the ankle. This muscle seems to be at least as often wanting as present. An insertion much like tlie present one is described by Humphry. Peroneus'longu-^ and hreoh are inserted respectively to the base of the first and of the fifth metatarsals. Neither has an}' further insertion. Extensor hrevls is remarkable oidy for the fact that the first division sends an additional insertion to the second phalanx of the great toe. The tibial and fibular flexors {flexor longus and flexor hallucis) are inserted as follows: the former goes to the second, fourth, and fifth toes, the latter to the first, third, and fourth. Flexor brevis is very small, arising in part from the os calcis. It divides into three little tendons for the second, third, and fourth toes. It receives muscular fibers in common with the lumbricales from the tendons of the long flexors which go to the third and fourth toes. This muscular slip represents the flexor accessorius. Lumbricales are four in number. The first arises from the tendon of the tibial flexor, the others from the tendons of tlie fibular flexor. The head of flexor brevis from the tendons is very confusingly mingled with the lumbricales. Adductor hallucis transversus arises from nearly the whole length of the fourth metatarsal and from the distal ends of the shafts of the second and third. Adductor obliquus is hardly separable from the preceding. It arises from the sheath of the peroneus longus at the basis of the second and third metatarsals. Interossei pedix. There is a great complication of these muscles, there being five or six both dorsal and plantar. The reason for this vague enumeration appears in the description. Dorsals. First muscle from the first and second metatarsal bones to the tibial side of the second toe. The second and third muscles arise each fr(nn two bones, and are inserted into the two sides of the medius, thus placing the base line in this toe. The fourth muscle is a very small one, placed on the dorsal aspect of the fourth metatarsal and inserted on the tibial side of the phalanx. Tiie fifth and sixth muscles arise together from the last two metata'"sals and are inserted into the .adjacent sides of the last two toes. This might be called a single muscle with two insertions. Plantar interossei. The first is where it should be, on the fibular side of the second 42 THOMAS DWKiHT OX toe. The second ami tliird are extra niuscle.s, each arising from mw side ol' the third metatarsal and inserted into rither side of tlie phalanx. The fourtli passes from the tibial side of the fourth metatarsal to its phalanx. The fifth arises from the fibular side of the fourtli metatarsal and is attached to both the fourth and fifth toes as is the dorsal. It differs from it by arising only from the fourth metatarsal. This excessive redundancy of interosseous muscles in the foot has not, I believe, been observed. Heart. The heart and great vessels, removed with the lungs, were in the center of a mass of disease intensely repulsive. At my request a veteran dissector undertook to make a careful dissection of the roots of the lungs and the chief vessels. He was obliged after several hours' work to give up the task. The heart was therefore cut ol¥ from the rest. The left auricle was cut so close that nothing of the pulmonary veins is to be seen. The branches of the aorta could not be followed. Their identification is, however, from the manner of their arrangement, practically certain. The length of the heart (after preservation in alcohol) is 11.5 cm. and its breadth al)Out 8 cm. The external appearance is not unlike that of the liinnan heart. It seems relatively broader, and the origin of the aorta is less concealed by the pulmonary artery. The conus arteriosus is well marked; so are also the auricular appendices. The arch of the aorta gives off first an innominate artery about 1 cm. long which divides into the rio-ht subclavian and the right carotid. After an interval of 2 mm. the left carotid and the left subclavian arise close together, so close as at first to suggest a second innomi- nate. A minute vessel springs from the aorta just in front of the intej'space between the innominate and the left carotid, very probably a thyroidea ima, since Sutton has seen this. The subclavian arteries are much larger than the carotids, the lumen of the right sub- clavian being nearly 6 mm. in diameter and that of the right carotid less than 4 mm. Both these vessels on the right side are a little larger than their fellows of the left. Gratiolet and Alix, while noting this discrepancy between subclavians and carotids in the T. aubryi, comment on the relatively small size of all the four great arteries. In this sub- ject the carotids seem to me relatively as large as in man, and the subclavians relatively laro-er. The diameter of the lumen of the aorta iunnediately after the origin of the left subclavian is about 1 cm. Dr. Arthur Keith' finds accounts of the origin of the great vessels in eleven chim- panzees. In seven the plan was as in man. In three the left carotid sprang from the innominate. This, it may be noted, is not an uncommon arrangement in man. In one ' Jouni. anat. phy.siol., vol. 29. THE ANATOMY OF THE CHIMPANZEE. 43 case, that of Chapman, there was a sliort left innominate for the left carotid and sub- clavian. Dr. Keith remarks: " Such an oi-igin for the left carotid will probably be found to occur as a prevailing variation in the chimpanzee, for in another individual of that genus an approximation to that condition was observed." The last words express precisely the case of " Gumbo." Inside of heart. The right auricle much as in man. There is a well-marked annulus ovalis. The fenestra is completely closed. There is no remnant of an Eustachian valve, but on the right wall there is a long, slightly raised valvular fold separating the smooth part of the cavity from that part of the anterior wall bearing the musculi pectinati. The fold starts from the right side of the opening of the coronary sinus and runs upward and forward on the outer wall with an anterior concavity. The greatest height to which the valve could be raised from the wall could hardly exceed 3 mm. Its function, at most a very slight one, must be to hinder the regurgitation of blood towards the atrium. The feft auricle shows a lunated depression on the septum. The walls are smooth except in the appendix which is smaller than the right one. The walls of the right and left ventricles present about the relative thickness observed in man. The cavity of the right ventricle is traversed about half way up by a muscular moderator band some 3 mm. in diameter. The three parts of the tricuspid valve are not very easily distinguished. There is a large right one and a large septal one which meet behind. A small infundibular segment might be reckoned a part of the right one. The inside of the right ventricle presents a great development of columnae carneae. The interior of the left ventricle is striking. The surface of the septum is perfectly smooth except near the apex. The outer side presents a wonderful network. The mitral valve is as in man. The great arteries were not split open, so that the valves cannot be thoroughly examined. They apparently are not remarkable. The Arteries. The axillary artery gives off an anterior and a posterior circumflex which arise from a! common trunk. The posterior runs round the neck of the humerus as in man, with the circumflex nerve. It sends a branch down the back of the arm between the external and the long heads of the triceps. The brachial artery runs as in man. It gives off almost at its origin a branch which supplies the inside of the arm and another which luns with the niusculo-spiral 44 Tiio:\jAs J) WIGHT ox nervL'. The two [(rcsiiiiiiibly represent the superior profuuda. Later a small branch runs to the under side of the biceps, ami a few su[)ply the elbow joint. The division into radial and idnar occurs about one inch below the elbow joint. The whole arrange- ment is as in man (very different from T. auhrtj't) ; the radial descends in the usual way to the tabatiere, and then passes into the depth of the palm. The ulnar, which is the larger branch, passes under the pronator teres, the deep head of which separates it from the median nerve. Its distribution in the hand is essentially human. An interosseous artery was given off which was subsequently lost. With the exception above mentioned this in essentials corresponds to other chimpanzees. The femoral artery about one inch below Poupart's ligament gives oft" a small external branch, probably the external circumtlexa, ilii, and, a little lower, a small one running internally. At about the same level the profunda arises from its deep aspect. From this .springs an external circumflex which divides into ascending and de.scending branches and a small lateral one. The descending runs on the vastus externus to the outside of the knee. The profunda runs probably ' through the thick ma.ss of adductor muscles, sending back perforating branches. The femoral runs anteriorly to the adductor mass to the inside of the lower third of the thigh, where beneath the sartorius and the anterior border of the gi'acilis it divides into the popliteal and the saphenous. The popliteal, which is rather the larger of the two, passes back external to the muscle representing the vertical part of the adductor magnus. Be.sides articular branches it a-ives one lono- sural branch and divides into the anterior and posterior tibials. The former passes forward at once as in man and descend- ing to the ankle ends in a network over the metatarsal bones. The posterior tibial gives off a peroneal branch, neither of which was fully traced. The saphenous artery gives a considerable branch to the inner side of the knee joint and passing between the sartorius and gracilis comes to the surface opposite the inner tuberosity of the tibia. It then runs down along the inner side of the leg in company with a vein beneath the fascia. It crosses above the internal malleolus to the front of the foot and plunges into the sole between the leases of the first and second metatarsal bones. Gratiolet and Alix describe the arteries of the lower leg practically as here. They say, however, of the saphenous artery that " Elle se place superficiellement sous la peau, le long de la face interne dn tibia, etc.," while I find it beneath the fascia. Zucker- kandl" does not touch on this point. My observations, though less minute, agree with his, only that he finds the peroneal springing from the anterior tibial. ' I regret that my notes on tlii.spuiiit are not jierfeotly clear. - Auat. liefte, la, 18y0. THE ANATO^rV OF THE CHIMPANZEE. 45 The Larynx. The general shape and structure are well known. Seen from above and behind (the posterior wall of the cricoid having been divided in the median line), the larvnx is pro- portionately narrower than in man. The epiglottis is smaller and far less prominent. The fossae at the back of the tongue and tlie glosso-epiglottidean folds are much less marked. Another and more important consequence is, that the aryteno-epiglottidean folds bounding the entrance to the larynx proper do not project nearly so freely as in man. The notch behind is narrower and deeper. The prominence on either side formed by the cartilage of Santorini is further forward, taking the place occupied by the cartilage of Wrisberg, which in this animal is wanting. The hyoid apparatus consists, as usual in apes, only of the basi-hyal and of two thyro-hyals. The body of the bone is short and strongly cru'ved upward as well as forward. Its breadth measured in a straight line from side to side is 2.4 cm. The thyro-hyals, which are connected by joints, measure, the right 4.2 cm., and the left 3.8 cm. The two halves of the thyroid can be separated or approximated with such ease that a want of union was suspected, but a cross-cut at the angle showed that the cartilage is continuous. There is but a slight forward projection of the angle. The vertical length of this between the two notches is 2.2 cm. Both cornua bend strongly inward, especially the upper. Tiie oblique line ends below in a very prominent tubercle which overhangs a deep fossa. The fibers of the crico-thyroid muscle are inserted into the lower border of the cartilage, the tubercle, the fossa behind it, and the inferior cornu. There is a suggestion of a separation into two layers described by Gratiolet and Alix Tlie superior cornu is separated from tlie extremitj- of the great horn of the hyoid In' a nodule (cartilago triticea) which touches both. The flexibility of the superior cornu is very striking. The cricoid cartilage has not been uncovered, for it was thought best not to dissect the larynx. Its height in front is 7 mm. and behind 2.1 cm. The arytenoids, for the same reason, are not accessible. The true vocal cord is 2.-3 cm. in length. Its delicacy has been described by others. It seems nothing more than a very thin fold of mucous membrane. The greatest distance between the true and false cords across the middle of the entrance of the ventricle is 5 mm. The ventricles and the roaring sac. Each ventricle is prolonged upward behind the h3n)id to the side of the epiglottis for more than 1 cm. from the superior curd. The 46 THOMAS DWKillT ON left ventricle ends blindly. The right ventricle opens at its anterior part^by an opening, which it is hard to see from the inside, into an anterior expansion. A rod G nun. in diameter, introduced from in front, fully distends the passage. I regret that 1 was not present when the roaring sac was opened by the primary incision at the autopsy. It was described as immense, extending over the front of the neck and the top of the chest outward as far as the coracoids. The portion still connected with the specimen passes up under the hyoid where it is sacculated. The communication with the larynx is just to the right of the median line. The Tongue. This organ seems hardly to have received the attention it deserves. It is longer and broader than in man. While strikingly similar, it presents some noteworthy differences. As in the human tongue the anterior two thirds of the dorsum are to be sharply distin- guished from the posterior one, which has the papillae circumcallatae near its front and is occupied by adenoid tissue and mucous glands. In " Gumbo " the anterior two thirds besides the filiform papillae have very nitiny fungiform ones, especially near the tip. What is remarkable is, that the characteristics of the dorsal mucous membrane are prolonged at the tip onto the inferior sui'face for 5 mm. or more. In the posterior third there is an oval swelling of the whole tongue in the middle, while in man there is a median furrow. The circumvallate papillae, some seven in number, are arranged rather like aT than a V. In some cases two papilhie are surrounded by the same mote. The surface of the very posterior part is very irregular, owing to accumulations of adenoid tissue. Very striking is the large number of orifices looking like small pin-holes to the naked eye. Whether these are really the openings of large ducts or simply little cavities between adenoid collections can be determined only by the microscope. The papillae foliatae are more strongly developed than in man. These constitute a system of trans- versely placed ridges and furrows extending along either side of the tongue just in front of the end of the anterior pillar of the fauces. This system describes a marked curve with an inward convexity. From this in the anterioi- part of the posterior third of the tono-ue among the large papillae and .somewhat in front of them is a curious system of curved raised lines suggesting that of the tips of the fingers. The Caecum. The caecum (pi. 8.) was the only part of the intestines saved. The vermiform process was divided some six inches from its origin, so that its length is not known. The THE ANAT0:MV of the CHIiLPANZEE. 47 caecum is not unlike a human one, being broiider than long. It is a good example of Treve's third chiss, namely, that commonly found in man. It is very different from that figured by CTratiolet and Alix, which is long and tapering. A window cut in the dried and inflated specimen shows an ileo-caecal valve extending obliquely upward and outward from the inner side of the gut so as greatly to increase the size of that part of the intestine which must be called the caecum. The slit is 2.4 cm. long. The valve is continued about two thirds of the distance round the gut. Its greatest breadth is about 3 cm. Beneath it in the caecum, starting at the inner side from its under surface, is another smaller fold which diverges from it. This is best marked toward the posterior surface of the caecum. There is a small valve guarding the upper part of the entrance of the appendix. The ascending colon is very large and strongly sacculated. The Brain. According to agreement, the brain was so hardened as to make it fit for microscopic sections. The hemispheres were put at my disposal for the study of the convolutions. The length, after hardening, is 11.2 cm., the breadth, 9.4 cm., the height, 6.7 cm. Seen from the front there is a strong median downward projection of the frontal lobes where they rest on the cribriform jjhites. This keel is much greater than in " Sallv," but perhaps a little less than in Benham's^ figure of a common chimpanzee. The points which at first sight are most noteworthy and characteristic of this particular brain are the large size and diagrammatic appearance of the frontal and occipital convolutions in contrast to the small size and complication through small fissures of the parietal and temporal ones. There is a decided want of symmetry between the two halves. Fissure of Si/lvhcs. The main limb ends with a bifurcation on both sides of the brain. On the left side the anterior limb is easily recognized. It runs forward and ends in a bifui'cation, the two parts of which make a slight concavity around a part of the third frontal, representing clearly enough the j»^«/'s triangularis, Broca's promontory (pi. 9, fig. 1). In short, this is the Y plan often seen in the human brain, only the arms of the Y are short and widely opened. On the right there is no anterior limb at all, unless a depression on the third frontal in front of the praecentral fissure can count as a rudiment. This is precisely where the fissure should be. The little suhcentralis anterior and i\\e praeeentralis are behind it and the orhitofrontalis in front of it. If the identification on the left side be correct, it will be observed ' \ description of the cerebral convolutions of the cUiraiianzee known as ■■ Sally," etc. Qnart. journ. niicr. sc., Xov., 1804, pi. 7. 48 THOMAS DWIGHT ON that in front of the fissure of Rohuido we find in order, first, the anterior suhcentralis then the praecentralls, then the anterior limb of the Sylvian, and finally the fronto- orhitalis (of Kiikenthal and Ziehen'). The snine series on the right is found by the interpretation offered above. Fissure of Rolando. Exceedingly plain and diagrammatic on the left, sliowing very clearly the two knees. The upper end opens on the mesial surface. The lower does not reach the Sylvian fissure. The same is essentially true of the right fissure, but the knees are less well marked. The fissure cuts the median line at a distance of about 6.5 cm. measured directly backward from a. sti-aight line at the front of the bi'ain. The frontal lobe must be described separately on the two sides. The left is taken first, as more resembling the human brain. The anterior centi'al ct)nvolution is much larger than the posterior. It is directly continuous with the three frontal convolutions, the first at the side of the median fissure, the second a little above the middle, and the third at the lower end. The middle convolution divides the praecentral fissure into a larger inferior and a smaller superior part. Each of these receives a sulcus frontalis ; the superior is short, ending in a bifurcation ; the inferior is long and complicated, running to the very front of the brain where it ends with a sweep inward. There is another fissure (?pl. 10, fig- 1) very like one described by Benham in " Sally " wliich also has its upper end internal to the frontalis siqjerior. It is well marked and deep, with an external branch. It is not clear whether it is to be called a continuation of the sulcus frontalis primus or a frontalis mesialis. The second frontal convolution fuses with the fii^st at the front of the brain. The third frontal convolution arises from the very lower end of the anterior central, runs at first upward, then, turning forward, it surrounds the bifurcated anterior limb of the Sylvian fissure, forming a rudimentary but distinct 2^'^'''>'^ triangularis. In front of this, it rises again to loop round the sulcus orhito-frontalis, which is a striking fis- sure. The inferior or orbital surface of the frontal lobe is not easily understood. A small fissure running to the mesial surface must represent the olfactory fissure. The general direction of the other fissures is forward and inward. The sulcus orhito- frontalis bounds it externally but behind runs into its inferior surface. The right frontal region is very different in some important respects. The anterior central convolution is larger than the left one, consequently its predomi- nance over the posterior is more marked. The second frontal convolution is very large in its first pai-t. The superior praecentral sulcus is longer than on the left. The superior frontal sulcus runs forward almost to the orbital border of the brain. This is a very uncommon development of this farrow wiiich I do not remember to ' Untersuchungen liber die grosshirnfurclien der primaten, Jena, zeitselir., vol. 20, 1894. THE ANATOMY OF THE CHIMPANZEE. 49 have seen equalled in any figure of a chimpanzee brain. The sulcus praecentralis inferior almost reaches the fissure of Sylvius. Owing to the absence of the ante- rior limb ot" the fissure of Sylvaus, the third frontal convolution at this region has the shape of a solid wedge placed base downward with an indentation on its surface which represents the anterior limb. It then winds over the sulcus orhito-frontalis. The second frontal fissure is interrupted by an annectant gyrus between the second and third convolutions. On the inferior surface, the olfactory fissure does not run to the median line. There is a deep fissure in the posterior part of the orbital surface curving forward and outward, which has no represen- tation on the left. Tlie median surface of the frontal lobe is left to be taken later. The parietal lobe. The external parieto-occipital fissure, by which is meant that part of the internal one of the same name which extends into the convexity of the brain, is about 2 cm. long and similarly disposed in each hemisphere. It is surrounded by the arcus parieto-occiintalls, the classical jili de passage, which is quite uncovered by the operculum, but a little shut in anteriorly by the parietal lobe. The sulcus occipitalis transversus (Affenspalte), also symmetrical in the two halves, runs from the median line, just behind the arcus to the outer, lower, border of the hemisphere. In the first three quarters of its course it runs outward and slightly forward, then it bends strongly down- ward. The intra-]>arietal fissure is simple and nearly symmetrical. It consists of an inferior vertical part which is continuous with the main (horizontal) portion which runs into the Affenspalte just below the arcus. The superior vertical part is distinct. It can be called " vertical " only by homology, for it is decidedly more horizontal. The main limb just before entering the Affenspalte sends off a small branch which runs just in front of the arcus toward the median line. The posterior central convolution is small. On the right it is evidently continuous along the whole length of the fissure of Rolando. It is continuous also on the left, though less evidently, for it is nearly cut through at the two knees of the fissure of Rolando above by the upper detached portion of the intra-parietal fissure, and below by a sulcus from the main stem. At the lower end this convolution expands on the left side into a triangular mass with a centr.il imprint, probably- representing the sulcus suhcen- tralis posterior. The superior parietal convolution consists of two gyri separated in front by the upper part of the intra-parietal fissure which is hei'e essentially horizontal. They unite behind it and are continued into the parieto-occipital arcus, bounding the fissure of that name, which is quite uncovered by the operculum. The inferior parietal convolution divides into the supra-marginal gyrus surrounding the fissure of Sylvius and the angular gyrus which descends to the edge of the hemisphere 50 THOMAS DWKllIT OX and then, rising sharply, is continued as the second temporal convolution. Tliis a]iplies to both sides. The temporal lobe, so far as seen on the outside, requires little description. The parallel fissure below the first temporal convolution is, as seems always to be the case in the chimpanzee and in all the higher primates, remarkably clear and simple. It ends above with a bifurcation, around the lower branch of which the angular gyrus has to turn to reach the second temporal convolution as just described. The first temporal convolution is .self evident. The second and third seem to be somewhat fused on both sides. Those on the nnder surface of the lobe will be -con.sidered later. The occipital lobe, as seen externally, is marked by the large size and extreme simplicity of its convolutions. It looks like an undifferentiated mass on which a capital tH has been imprinted, lying on its side with the stem forward. Tins is the s. occipitalis obliquus. The gyrus occipitalis secundus (the operculum) lies behind the Atfenspalte and joins the angular gyrus; before doing so, however, it is itself joined by the thii-d occipital which lies under the ^ . Beneath this runs the sulcus occijntalis inferior just above the lower edge of the hemisphere. This fissure is well marked on both sides, giving off a vertical ascending branch, round which the second temporal convolution turns. On the right the middle part of this fissure is not visible from the side. The median surface of the brain and the inferior aspect of the occipital and temporal lobes remain to be described. The Jissura cnlloso-marginalis is very simple and so like that of the human Ijrain that detailed description is needless. It begins on the right hemisphere far l)iick on the mesial surface of the frontal lobe, and is uninterrupted. On the left the plan is much like that figured by Kiikenthal and Ziehen. There is below a sulcus rostralis with which the calloso-marginalis is joined by a little fissure so minute and shallow that the junction is more apparent than real. Behind its termination is the lohulus quadratus which is connected with the arcus parieto-occijntalis above and with the gyrus fornicatus below. Tlie last named convolution and its continuation, the gyrus hypocampi, are uninterrupted on the right. On the loft it is divided by the Jissura ccdcarina. The uncus is well marked. The internal parieto-occipital fissure is similar on both sides. Seen from the mesial surface, it appears to split above into two parts. The posterior one is the true fissure, being continued out into the convexity as above described. The anterior branch just passes the upper l)order of the heniLsphere. The gyrus intercuneatus is made out by separating the parts as far as possible. It is quite hidden, being very deeply placed. Should it rise to the surface, it would separate the internal parieto-occipital fissure from the external, making the former end anteriorly to the latter, as Benhani has THE ANATOMY OF THE CHIMPANZEE. 51 shown. The lower end of this fissure divides into two small branches which connect with no other fissure. In tlie right hemisphere the posterior division almost cuts through the gyrus separating it from the calcarine fissure. The calcarine fissux*e differs in one important respect in the two sides. In both it ends in a. fork very near the hind end of the brain. On the left it opens into the Jissura hypocttmin ; on the right it joins what seems to be a peculiar collateral fissure. A deep fissure is seen in the cuneus, which, according to Kiikenthal and Ziehen, is very constant in the chimpanzee. On the left the cuneus sends a convolution to the gyrus hypocampi just above the end of the calcarine fissure ; on the right, owing to the peculiarity of the calcarine fissure, this gyrus seems to run more directly into the gyrus hypocampi. The under side of the temporal lobe presents a very different appearance in its anterior half, which is frankly inferior, and in the posterior portion, which slants into the oblique inferior occipital surface. The former shows large simple convolutions. The latter is broken up by many secondary sulci. The former shows the ends of the first and second temporal convolutions passing obliquely forward from the outside of the brain and behind them the third which is quite plain on the under surface of the left half, but not clear on the right. The left collateral fissure is perhaps best described as splitting- posterioi'ly into two parallel divisions. The lohulus lingualls lies between the inner of these divisions and the fissura calcarina. Tlie lohulus fusiformis is between the two divisions. On the right the Jissura calcarina runs obliquely outward across the under surface of the temporal lobe to end in a short fissure which represents the separated anterior portion oi Jissura collateralis. The posterior part of this fissure is in its j^roper place. The lohulus lingualis is cut off by the abnormal direction of the Jissura calcarina. The arrangement is, so far as I know, an undescribed one. EXPLANATION OF THE PLATES. PLATE 7. Fig. 1. Foot. Fig. 2. Hand. PLA'rE 8. Fig. 1. Caecum. Tlie appendix runs along the lower edge to the left of the caecum till lo.st to .sight behind the ileum. Fig. 2. Inside of caecum. The ileo-caecal valve is seen above. Below this a valvular fold in the caecum, and still lower the opening of the appendix. Fig. 3. The upper end of the left femur, showing a small, but distinct, thinl trochanter. PLATE 9. Fig. 1. The outer surface of the left hemisphere of the brain. Fig. 2. The outer surface of the right hemisphere of the brain. 52 THO.MAS DWIGHT. PLATE 10. Fig. 1. The brain seen from above. Fig. 2. Inner aspect of the right liemispliere. LETTERING USED IX PLATES 9 AND 10. af. Affenspalte : sulcu-s uixipitalis transvei'sus. fc. Fissura calcarina. f. coll. Fissura collateralis. f. p. o. Fissura parietooccipitalis. f. po. ext. Fissura parieto occipitalis externa. f. R. Fissui'e of Rolando : fissura cei^tralis. r. asc. f. s. Ramus ascendeus, vel anterior, fissurae Sylvii. s. c. m. Sulcus calloso-marginalis. s. i. p. Sulcus intra-parietalis. s. 00. ob. Sulcus occipitalis obliquus. s. o. f. Sulcus orbito-frontalis. s. o. i. Sulcus occipitalis inferior. s. pc. i. Sulcus praecentralis inferior. s. pc. s. in plate 10 should be r. s. i. p. for the separated superior branch of the intraparietal fissure. s. sub. 0. a. Sulcus subcentralis anterior. s. sub. c. p. Sulcus .subcentralis posterior. ? Vide page 48. PUBLICATIONS OF THE BOSTON SOCIETY OF NATURAL HISTORY. PROCEEDINGS. 8vo. 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I had no difficulty in satisfying myself that it, as well as Ludwig's Abrolhos specimen, was indeed Orsted's Synaptula vivipara. A brief description to establish its position in the genus Synapta, was published by Clark ('96), and attention was there called to its similarity to 8. picta Theel ('96). This species was described from a single specimen in the Challenger collection, from Bermudn, and the agreement of all its characters with those of S. vivipara was very striking. Dr. Theel writes me that he has specimens of a viviparous Synapta from Bermuda in his hands at the present time, which agree with S. picta and S. vivipara so completely that he has no doubt that all three are the same, species ; but the evidence is incomplete, owing to the absence of the anchors and plates in his Bermuda specimens, caused by the killing agent used. Although, as we shall see, Synapta vivipara differs in several important particulars from all other Synaptas hitherto described, they are not sufficiently obvious to warrant its separation, under the existing classification of the Synaptidae, as a distinct genus. Synap- tula must therefore become a synonym of Synapta, and the synonomy of S. vivipara will be as follows : — Synapta vivipara (Orst.) Ludw. Zool. Jahrbiicher. Bd. 2, p. 28. 1886. Synaptula vivijxira Orsted. Vid. med. fra d. nat. For. i Kjobenhavn for 1849-50, p. vii. Synapttcla vivipara Bronn. Klas. und Ord. d. Thier., Bd. 2, p. 403. 1860. Synaptula vivipara Selenka. Zeit. f'tir wiss. Zool., Bd. 17, p. 365. 1867. Synaj)tula vivipara Semper. Reis. in Arch. Phil., 2. Theil, 1. Bd., p. 24. 1868. Chirodota rotifera (in part only) Lampert. Die Seewalzen. Wiesbaden. 1885. Synaptula vivijjara Theel. Report on the Holothurioidea. "Challenger" Reports, Zool., Vol. 14, p. 32. 1886. Synapta picta Theel., p. 10. Report on the Holothurioidea. "Challenger" Reports. Zool., Vol. 14, p. 32. 1886. 3. Distribution and Habits. Orsted's specimens of Syiuq^ta vivipara, he tells us, were from the West Indies, and all of the specimens I have seen, came from Jamaica. Ludwig's single specimen came from the Abrolhos Reef off the coast of Brazil (18° S. lat.), while all of Theel's specimens are from Bermuda (32° N. lat.). We may therefore conclude that the species is pretty 56 HUBERT LYMAN CLARK ON widely distributed throughout the eastern AtUintic ocean, wherever suitable conditions are found. In Jamaica, however, the species is extremely local and was found in only one place, the so-called "lakes" at Port Royal. These "lakes" are parts of the harbor which have been wholly or in part cut off by the growth of mangroves, so that they are very quiet bodies of water, though not at all stagnant or brackish. On the roots of the mangroves, which hang down in the water on all sides, is an abundant growth of vegetable and animal life. In some places, a particular sea-weed, one of the Florideae, crowds out all the other Algae. In this weed Synapta vivlpara makes its home, and though carefull}'' looked for elsewhere, it was found in numbers only in sucli situations. The late Dr. J. E. Humphrey kindly identified this alga for me, as Acanthophora thierii Lamouroux. This weed also grows in large bunches on the bottom in the shallow water of the harbor just outside the " lakes," and I was told that in 18'.J3 the Synapta was found in great quantities there, but in 189G it seemed to have entirely disappeared from that place. At Montego Bay, on the northwest coast of Jamaica, Acanthophora is very abundant on the mangrove roots, but a thorough search revealed no sign of Synaptas there. Even in the Port Royal "lakes," their distribution was very capricious, and only certain favored masses of Acanthophora contained them in any numbers. They seem to be quite social in their habits, and usually if one or two were found, there would be a whole colony of them. They are very sensitive to changed conditions, and I was unable to keep them alive in aquaria more than twenty-four hours. The anchors in the body-wall are so abundant and prominent that they cling very tenaciously to anything with which they come in contact, especially the hands, and it is accordingly no easy task to disentangle them from the sea-weed without injury. They seem to be able to swim very little, and it is doubtful if they ever leave the bunch of sea-weed, in which they have once settled. Their food consists largely of vegetable matter, diatoms being abundant in the stomach, but probably many small crustaceans and worms are also eaten. The tentacles are kept constantly in motion, and it was very common to find small amphipods caught among them, but I was unable to find evidence that these crustaceans ever served as food. Semon ('87) has called attention to what he considers a mimicry of coloration in Synapta inhaerans, in relation to the bottom on which it is found. In this connection, it is interesting to note that the reddish and greenish brown shades of S. vivijjara are almost exactly those of the Acanthophora in which it lives. So close is the resemblance that it is very easy to overlook Synaptas, even when the sea-weed is in one's hand. Whether this coloration is actually protective or not is doubtful, for they seem to have few, if any, enemies. No internal parasites were observed ; externally however a small brown calcareous sponge, like Grantia, was found firmly attached SYXAPTA VIVIPARA. 57 to the skin, just behind the circle of tentacles. When placed in aquaria, this Synapta does not break up by muscular contractions, like S. inhaercms, nor does it ordinarily eviscerate like many holothurians, but after crawling about restlessly for a while, it stretches out on the bottom and dies, almost without the contraction of a muscle. In a few cases, evisceration at the mouth took place, when they were thrown into a killing agent. Breeding goes on all thiough the spring and summer ; and there is no evidence to sliow that it does not go on all the year round. My earliest specimens, collected April 30 contained many well-developed young, and up to the end of July in nil the specimens obtained, young were found, while Ludwig's specimen from Abrolhos was collected in September and contained very young embryos. The number of young in the body- cavity of a single adult varies greatly, depending more or less on the size of the individ- ual. Specimens not over a centimeter long may contain a few, while some very large ones have scores. The largest number I have found is 176. It is a curious fact that the young are almost always in two broods ; that is, a certain proportion of them will all have reached a given age, say that of the pentactula, while the i-emainder will be much younger, say about that of the gastrula. When the young are very few, they will all be the same age, while if they are very numerous, they will sometimes show three different stages. This fact seems to indicate that the eggs ripen and pass into the body-cavity in lots of from six to a hundred, and tliat several days elapse before another lot is ripened. Regarding the length of time during which the young remaiu in the body-cavity, it is impossible to make even an estimate. Animals kept in aquaria frequently gave birth to young only five mm. long, and it was not usual to find much larger specimens in the adults examined, but sometimes a young one, fifteen or twenty mm. long, witli all the charac- ters of the adult, would be found still inside its mother. Observations made on the living animals showed that birth occurs normally at the posterior end of the body, apparently through the anus. Investigation showed that this was accomplished by a rupture of the body-wall, which may be through the skin some little distance from the anus (Fig. 29), or, as seems to be more generally tJie case, through the wall of the rectum close to the point where it joins the external body-wall, the young passing out through the anal opening. It may be that the openings in the wall of the rectum (Figs. 30 and 31), to be described later, are concerned in the birth of the young, but they seem to be too small to be of any service in this connection, except possibly as starting points for the rupture of the rectum wall. Under abnormal conditions, I found by experiment, rupture of the body-wall and consequent birth of the young may occur at other points than near the anus. 58 HUBERT LYMAN CLARK ON 4. Fertilization and Segmentation of the Egg. Like all other known Synaptas, S. vivipara is hermaphroditic. Ripe spermatozoa and ova are found in the same genital organ and even in the same branch, and to judge both from living material and preserved specimens, even at the same time; but this latter point could not be proven since it is impossible to determine simply by observation, when the egg is mature. The branches of the genital gland are nile-green in color in the living animal, while the fully grown ova are brownish yellow, and the spermatozoa, when in any quantity, appear to be white. In shape, the latter are like those figured by Jourdan ('83) for Holothuria tubulosa. The mature egg (Fig. 1) is about 2001* in diameter and before fertilization is not provided with any membrane. It is full of yolk material but comparatively transparent, so that the internal changes could be watched up to a late stage of development. Artificial fertilization proved unsuccessful, although attempted sevei'al times. Whether self-fertilization takes place or not could not be positively decided, but that it is at least very improbable seems clear from the structure of the genital organs and the probable manner of egg-laying. The genital gland of the adult Synapta lies just above the oesophagus, with one or two branches on each side of the dorsal mesentery and with the genital duct lying in that mesentery and opening to the exterior close to the base of one of the mid-dorsal tentacles. A cross-section of one of the branches (Fig. 40) shows that it consists of an external covering, the continuation of the epithelium, a very scanty connective-tissue layer consisting only of a few scattered mesenchyme cells, and a much folded germinal epithelium surrounding the lumen of the gland. Of the layer of circular muscle fibers which was found in the genital gland of S. digitata and S. inhaerans by Quatrefages ('42), Baur ('04), and Hamann ('84), I have found no trace in S. vivipara. The branches of the gland contract vigorously after being cut from the body, but so far as I could see, these contractions were always longi- tudinal. The germinal epithelium is more or less plainly made up of two or more layers of cells of which the external are the largei'. As will be seen from figures 39 and 40, from this external layer of cells the ova arise and so come to lie between the germinal epithelium and the epithelium of the body-cavity, and do not pass into the lumen of the gland at all. This arrangement is quite the reverse of what Cuenot ('91) has shown to exist in ;S'. inhaerans, and gives us a clue as to how the eggs get into the body-cavity of the mother. When the eggs are mature, they press so closely against the external epithelium of the gland that it bulges out sufficiently to be seen with the naked eye, in the living gland. Sections show that the epithelium over such ova is so stretched as to be thinner than elsewhere (Fig. 39), and probably the eggs enter the body-cavity simply SYNAPTA VIVIPARA. 59 by the rupture of the epithelium at that point. While this has never been actually observed, the theory is supported by a further examination of the genital gland. The smaller internal cells of the germinal epithelium give rise to spermatozoa, which are almost invariably to be found in the lumen of the gland, never on the outside with the ova. If we trace the lumen forward we find it passes directly into the lumen of the genital duct, the internal walls of the latter actually being formed by a continuation of the germinal epithelium, which has become of uniform thickness and ciliated internally (Figs. 36 and .37). The lumina of the two or three branches of the gland unite on entering the duct (Fig. 36) and pass through the latter upwards towards the body-wall- At no point is there any sign of communication between the genital duct and the space external to the germinal epithelium in which the ova lie. If we follow the genital duct upwards to where it comes in contact witli the body-wall, we find it does not fuse with the ectoderm and open at once to the exterior, but simply lies in the connective tissue with its end against the ectoderm (Fig. 38), and although there are probably openings through which the spermatozoa pass out, they are so extremely small I have not been able to demonstrate them satisfactorily. In nearly all the specimens examined the genital duct contained large quantities of spermatozoa, but in no case was there any trace of an ovum. That the openings at the end of the duct are not directly continuous with openings through the body-wall is indicated by the occurrence of spermatozoa, sometimes in large quantities, in the connective tissue surrounding the terminus of the duct (Fig. 38). From all these facts I am convinced that the ova pass into the body-cavity by a rup- ture of the peritoneal epithelium, while the spermatozoa pass outward through the genital duct to the exterior. In Cucumaria glacialis, the only other viviparous holothurian concerning whose breeding we have any information, Mortensen ('94) .thinks the eggs are laid on the bottom and taken up afterwards into the brood-sacks of the mother. But it is manifestly impossible that the eggs of *S'. vivipara could get into the body-cavity in any such way. The next question that arises is, how do the spermatozoa reach the ova inside the body-cavity of the mother, and the answer^brings to light another interesting modification of structure, adapted to the viviparous habit. Careful examination of the rectum shows that through its wall there are direct channels of communication between the body-cavity and the exterior through the anus. The wall of the rectum is folded and ridged longitudinally, and at certain places, parts of these ridges have pushed out and fused with invaginations from the surrounding coelomic wall, forming distinct tubes connecting the interior of the rectum with the interior of the coelom (Figs. 30 and 31). No trace of valves or cilia was found in any of these tubes, but the passage of water in and out could be easily regulated by the opening and 60 HUBERT LYMAN CLARK OX closing of the anus. With the anus open, each muscular contraction of the animal would tend to either force water out or draw it in through these openings, and in that way spermatozoa could easily get into the body-cavity and thus fertilization could take place within. This will appear more probable when it is remembered that the animals are very social, and that the water around a mangrove root on which there are hundreds of them, must contain countless spermatozoa. There is also a possibility that spermatozoa enter the body-cavity, through the water-pore and stone- canal, which, as we shall see, remain open in the adult, and also open into the body-cavity. After fertilization a membrane forms around the egg and segmentation begins. It seems probable that the extrusion of the polar bodies occurs before the formation of this membrane, as Selenka ('83) found no trace of them in the segmenting eggs of .S'. digitata, and 1 could not find them in any of the eggs of .S'. vwijmra which I examined, although they were looked for with special care. Segmentation and the formation of the blastula occur in practically the same manner as has been so well figured by Selenka ('83) for 8. digitata. Tlu^ first plane of division forms two blastomeres of equal size and appear- ance (Fig. 2). After a resting period of about twenty minutes, the second plane of division occurs at right angles to the first, giving rise to four similar blastomeres (Fig. 3). The third jilane is at right angles to the first two, and we now have an embryo of eight equal cells with a segmentation-cavity between them (Fig. 4). The sixteen-cell stage (Fig. 5) soon follows, the division plane being at right angles to the preceding. The appearance of the embryo at this stage is very peculiar and characteristic, the cells being arranged in a band or ring and the segmentation-cavity being open at each pole. Ano,ther plane of division, again at right angles to the preceding, doubles the width of the band and decreases the openings at the poles, but it does not divide the cells exactly equally, so that the upper- and lowermost rows are of somewhat smaller cells than the two middle rows and have a less diameter (Fig. 6 and 7). The subsequent divisions occur with a fair degree of regularity in alternating planes, each division decreasing the openings at the poles until at last they are entirely closed. This occurs when the embryo consists of approximately 256 cells, and so the blastula is formed (Fig. 8). The cells of the four equatorial rows are somewhat lai'ger than the rest, but the difference is not at all noticeable and apparently has no significance. The divisions have followed on each other with great rapidity so that the complete blastula is formed after about four hours, while in S. digitata, according to Selenka ('83), the blastula is the result of twelve hours' growth. It is for this reason, that I am inclined to think that the whole process of devel- opment in S. vivijmra is very rapid. SYNAPTA VIVIPARA. 61 5. Gastrulation and Formation of the Hydrocoel and Coelomic Vesicles. Invagination of one of tlie poles of the blastula soon forms the archeutei'on from the blind end of which the mesencliyme cells now begin to arise, some of the endodermal cells being simply crowded out into the segmentation-cavity. I could find no evidence at all of Selenka's ('83) two primitive mesenchyme cells, but on the contrary, I found cells all over the archenteron which were in various stages of passing into the segmentation cavity. On the other hand in not a single case were there found any of the ectoderma- cells forming mesenchyme, and I feel no hesitation in affirming that the mesenchymel arises exclusively from the endodermal cells, contrary to Ludwig's ('91) observations on Cucumaria. The number of mesenchyme cells is comparatively small, and they never become so numerous or play so important a part in larval structures as they do in S. digitatu, judging from Semon's ('88) account and figures. The completed gastrula (Fig. 9) is covered with cilia which are easily seen in the living specimens, but in none of my preserved material has it been possible to demonstrate them. In a few cases gastrula were found free from the egg-membrane and moving about actively in the fluid of the body-cavity, but the great majority are still enclosed in the membrane within which they rotate by means of the cilia. The membrane may be retained, as preserved specimens show, until long after the coelomic vesicles are formed, and I am inclined to believe that there is no definite time when it is cast off, but that it ruptures and is lost whenever the larva has grown too big for it. As the archenteron increases in length it bends to one side and unites with the wall of what subsequently becomes the dorsal surface of the larva. Its lumen breaks through the surface, and thus the water-pore is formed, as described by Selenka ('83) for *S'. dujitata. Meanwhile the gastrula loses its spherical shape and becomes more or less elongated (Fig. 10). The cells at the end opposite the blastopore are already somewhat different in form from those elsewhere and make a sort of plate of thickened ectoderm (Fig. 21) which may correspond to the so-called " neural plate " of other echinoderm larvae. This plate, however, does not lie exactly opposite the blastopore, but somewhat toward the ventral side of the larva, and as the gastrula increases in length, it comes to lie more and more on that side. At the same time, the archenteron continues to increase in length and grows forward and at the same time ventralward, thus drawing away from the water-pore. In so doing, that part of it which grows forward pushes by the part opening through the water-pore, on the right-hand side (looked at from the dorsal surface) so that the latter comes to lie on the left side of the larva (Figs. Hand 12). As the archenteron grows it completely severs its connection with this vesicle, and 62 HUBERT LYMAN CLARK ON pushing onward and downward against the thickened part of the ectoderm, becomes attached to it, and tlie mouth breaks tlirough at that point. The mouth may be formed before the separation between the archenteron and the other vesicle is completed. Mean- while the latter increases in size, and its walls become thinner. It grows backward toward the blastopore especially and soon becomes constricted and divided into two vesicles, the anterior of which is connected with the exterior by the water-pore, while the posterior is entirely closed and lies beside the posterior part of the stomach, if we may so designate the middle section of the archenteron (Fig. 13). Soon afterwards this posterior vesicle grows out laterally to the right, across the dorsal surface of the larval hind-gut, and forms on the right-hand side a vesicle like itself, which soon becomes entirely separate fi-oui it (Fig. 14). The anterior of these three vesicles is the rudimentary hydrocoel, while the pair of posterior pouches represent the right and left coelomic vesicles. Their mode of formation is essentially the same as that described by Selenka ('83) for S. digltata, but the relative size of the various organs is markedly different, so that the figures of the same stages show almost no resemblance. If figure 15 of Synajita vioiparu be compared with the auricularia of about the same age which Semon ('88, Plate 6, Fig. 2) figures, this difference will appear in many ways. The rudiments of the two coelomic pouches and especially of the hydrocoel are very much larger relatively in S. vivijxira than in S. digl- tata, while the difference in the digestive tract is even more noticeable. In the European species there is a well-marked differentiation into fore-, mid-, and hind-gut, while in the Jamaican form there is no such distinction evident. A remarkable difference is also to be seen in the external form of the larvae. That of *S'. vivlpara has retained its elliptical shape and shows no trace of ciliated bands, while tlie other has assumed the familiar auricularia form. Furthermore, there is no trace of calcareous structures of any kind in S. mvlpara to correspond with the plates at the posterior end of auricularia. In the latter also, Semon ('88) has figured and described a larval nervous system, but after care- ful investigation of this point, I am convinced there is none in the larva of S. vivipara. In external form, the latter is very regular-, but with the growth of the coelomic pouches the ectoderm of the dorsal surface begins to become thinner and more flattened, while that around the mouth, especially posterior to it, shows a tendency to increase in thickness. This difference between the dorsal and ventral surfaces may sometimes be seen in very young larvae and is clearly shown in figure 22. Before the two coelomic vesicles have entirely separated, the hydrocoel has become considerably larger and begins to grow anteriorly and toward the right, while about the same time five outgrowths begin to appear on that side which is furthest from the fore-gut (Fig. 15). Soon after their appearance five other much smaller outgrowths arise, one at the right of each of the first five. The SYPATA VIVIPARA. 63 first series gives rise to tlie five primary tentacles, and tlie second series corresponds to those which in S. dlyltata give rise to tlie radial water-canals. In >S'. dlgltata however, there is a sixth outgrowth at the extreme left, the rudiment of the Polian vesicle, but in »S'. vivijjara this vesicle is not formed until after the closure of the hydrocoel ring. The water-canal enters this ring at a point just between the fourth primary tentacle (counting from before backwards) and the fourth secondary outgrowth (Fig. 23). In this particu- lar my observations confirm Bury ('89) in opposition to the statements of Semon ('88). Before the outgrowths of the hydrocoel are very evident, that part of it which lies dorsally and in immediate connection with the water-canal bulges out, becomes thinner- walled than the rest of the hydrocoel, and gradually separates from it, but before the separation becomes marked, the outgrowth diminishes in size and with the increasing growth of the water-canal disappears. Tiiis structure, I believe, is the "anterior coelom " which Bury ('95) has shown to exist in the auricularia of S. digitata. It is very marked in some specimens of S. viinjjara (Fig. 24), and I see no reason to doubt Bury's interpretation. He does not make very clear what the ultimate fate of this coelom is in >S'. digitata, but leaves the impression that it is connected with the subsequent formation of the madrepore plate, as Ludwig ('91) considers it to be in Cucumaria. In >S'. vlvipara however, there is seldom any trace of it left after the hydrocoel ring closes, and there is no reason to suppose that it has any connection with the much later madrepore openings. About the time of the appearance of the primary tentacles, the larval anus, which was the original blastopore, closes entirely and the digestive tract ends blindly. Accordingly we now have a regular elliptical larva, about a third of a millimeter long, with the ventral ectoderm much thicker than the dorsal, without ciliated bands, calcareous particles, or nervous system, a mouth on the anterior ventral surface but no anus, a well-developed coelomic pouch on eacli side of the digestive tract, and a hydrocoel with five primary tentacles and five secondary outgrowths, opening to the extei'ior through the dorsal pore, by means of an adradial water-canal, upon which may still be seen the vestige of an anterior coelom. 6. The Development of the Pentactula. In such larvae, the ectoderm of the ventral surface continues to thicken and before long is sharply set off from the ectoderm of the rest of the body, which consists of a single layer of cells. The thickened ectoderm forms a circular field around the mouth though the latter does not lie at its center, but nearer to its antei-ior edge. This circular disc gradually sinks below the level of the rest of the ectoderm, and the latter grows in 64 HUBERT LYMAN CLARK ON over it from all sides, until the disc lies at the bottom of a shallow cavity, the so-called " atrium," whicli opens on the ventral surface through a small pore (Fig. 10). This pore does not lie directly over the mouth, but either befoi-e or behind or somewhat to one side. While the.se external changes are taking place, the hydrocoel has continued its growth, the anterior end passing across on to the right side of the larva where it bends downward and backward around the oesophagus to meet the posterior end near the middle line. The primary tentacles have increased considerably in .size and are growing up around the floor of the atrium, while the secondary outgrowths also grow upward beside them. No Polian vesicle has yet appeared, and no marked distinctions between the different parts of the digestive tract are to be seen, but the latter has become very much arched toward tlie dorsal surface, and the lumen of the middle section is larger than at either end. A new anus may have been formed by the end of the hind-gut growing to the body-wall on the ventral side and an opening breaking through, but in some cases the definitive anus does not appear until the pentactula form is nearly attained. The most important changes have been going on meanwhile in the coelomic pouches, the growth of whicli has l^een very rapid. The left vesicle has grown more ante- riorly than the I'ight, and sends forward two tinger-like processes, one of which passes across the median line into the right side of the larva, while the other grows up to the intier side of the hydrocoel ring, above the most posterior tentacle, and follows the course of that ring around the oesophagus (Figs. 26-28). These anterior prolongations of the left coelom were observed by Bury ('89 and '1)5) in S. digituta, but have appar- ently been overlooked by other investigators. The one which passes on to tlie right side of the body fuses so soon with the right coelom that I have been unable to confirm Bury's further observations regarding it, and in S. virijxira its appearance might easily be entirel}^ overlooked. But the prolongation which pa.sses to the hydrocoel remains distinct through all the later stages of the larva, and its subsequent changes are ea.>*y to trace. It soon loses its connection with the left coelom and forms a tube, lying on the oral surface of the hydrocoel ring. Meanwhile the right and left coelomic pouches have met and fused on the ventral side of the digestive tract, while dorsally they are still separate, the right pouch extending considerably further back than the left. The larva has now reached the cojidition shown in Fig. 16. In its subsequent growtli the atrium, with its thick ectodermal floor and narrow opening to the exterior, moves to the anterior end of the larva, where it finally comes to lie, along with the mouth, oesophagus, and hvdi'ocoel i-inii-. The latter has now closed, without the formation of a Polian vesicle, somewhat to the left of the middle line apparently (Fig. 25), but I am not sure that the point of closure is always on the left side, for it is by no means easy to determine the SYNAPTA VIVIPARA. . 65 exact mid-line. With the closure of the hydrocoel, occurs the union of the two ends of that coelomic tube which lies on its oral surface, so that we now have a circular sinus around the oesophagus just above the water-ring. This sinus is very evident in young Synaptas, and Bury's ('95) surmise regarding its origin from the left coelom is entirely correct. The primary tentacles are growing upAvard, not pushing the floor of the atrium out before them, as Semon ('88) says, but enclosing the atrium within their circle so that the thickened sensory epithelium, which they subsequently possess, does not arise as Semon describes. It is clear, from Figs. 16 and 17, that his description could not possibly appl}' to S. vivipara. The secondary outgrowths remain nearly unchanged in size and show no sio-n of bendino; backward to form radial canals. The Polian vessel is formed as an outgrowth on the inner side of the hydrocoel ring in the left dorsal interradius, as Ludwig ('23) found it to be in Cucumaria. The digestive tract grows with greater rapidity relatively than any of the other organs. Accordingly, the oesophagus jjushes upward toward the atrial opening, so that the thickened ectodermal floor of the atrium lies surrounding it, in the form of a poorly defined circnmoral ring. Continued growth pushes the oesophagus against the upper ectodermal wall of the atrium, and with that it fuses, leaving the circumoral ring entirely cut off from the outer ectoderm of the body (Figs. 87 and 88). Meanwhile the growth of the primary tentacles has pushed this body-wall upward and outward, so that the narrow slit-like opening of the atrium is gradually widened until it finally disappears, leaving the ectodermal-covered, anterior end of the oesophagus to form the definitive mouth, in the center of the circle of tentacles. This process is not completed however, until the pentactula form is fully assumed. The differences between this development of the mouth and circumoral ring and that given by Semon ('88) for (S'. digltata are almost irreconcilable, but they are all dependent on the question, whether the five primary tentacles push up through the floor of the atrium or grow up around it. The latter is certainly the case in S. v'mipara. While these changes are taking place anteri- orly, the hind-gut has increased in length so that it has not only arched still more toward the dorsal surface but has bent on itself and formed a loop lying to the left of the stomach. The coelomic pouches already united and forming a single cavity ventrally, have met in, or close to, the mid-dorsal line and by the union of their walls have formed the dorsal mesentery. This mesentery follows pretty closely the curve of the intestine and attaches it throughout its course, to the l)ody-wall. The water-canal lies in the anterior part of the mesentery, but whether that part was formed in a different manner, as Bury ('95) thinks probable, it is impossible to say from observations on S. vivipara. Meantime most important changes are going on in the circumoral ring of ectoderm 66 HUBERT LYMAN CLARK ON which we have seen was formed from the floor of the atrium. This ring is the beginning of the central nervous system, and from it the tentacle and radial nerves arise. As the primary tentacles push upward past the atrium, they lie closely appressed to its floor and wall. They retain this position even after the circumoral ring is pretty clearly defined, and before they have grown much above it, the radial nerves appear between each pair of them as outgrowths of the central ring. These outgrowths pass directly over the secondary outgrowths of the water-vascular system and bend backwards to run toward the aboral pole of the body. Very soon after they appear (not before them, as Semon ('88) describes for S. diyitata), that part of the circumoral ring appressed to each primary tentacle begins to grow upward with it on its inner side, forming the tentacle nerves. As the tentacles continue to grow and press the anterior body wall outward, the ectoderm which covers them at the tip becomes noticeably thickened, especially on the outer side (Fig. 54), and apparently assumes a sensory function, probably in connection with the tentacle nerve. The formation of the otocysts of Thomson ('02), the " horor- gane " of Baur ('64), takes place as described by Semon ('88). They arise by evagina- tions from the outer side of the circumoral ring close beside the outgrowths which form the radial nerves. With the growth of the latter, the otocysts come to lie external to them at the point where they bend backward, and in this position the sense-organs remain throughout life. It is a very evident and noteworthy fact that the development of the radial nerves and otocysts does not take place at the same time in the five radii, but there is a marked difference between them. The first to appear is that nerve which subse- quently indicates the mid-ventral radius, and with it appear its two otocysts. The two lateral ventral nerves appear next, and witli them the otocyst which accompanies each one on its ventral side. The lateral dorsal nerves next appear (Fig. 1), and very soon after- wards the two other otocysts of the right and left ventral radii are formed. Last of all to develop are the otocysts of the right and left dorsal radii. This sequence in the appearance of these nerves and sense-organs is probably connected with the fact already mentioned, that the thickened ectoderm which made up the floor of the atrium did not lie symmetrically around the mouth, but the greater part of it was posterior or, when the mouth lies at the anterior end of the larva, ventral to it. What the significance of this condition may be, I am unable to suggest, but it is interesting to note that in Cucuniaria Ludwig ('91) found the ventral radius the most advanced in development. Any possible similarity ends here however, for the development of the other radii was quite the reverse in Cucumaria of what it is in Synapta. About the time of the completion of the pentactula form, there appear in the ecto- derm of various parts of the body peculiar invaginations (Fig. 41) -which are finally SYNAPTA VIVIPARA. 67 connected with the exterior only by a very narrow canal (Figs. 42 and 43, and Fig. 17, Igo.). These organs appear, from their structure and the great variation which they show in staining, to be of a glandular nature, and I am inclined to think they may be connected with the absorption of nourishment from the fluid of the body-cavity of the mother, for they never increase in size, are most abundant in the young with ten tentacles, and seem to have entirely disappeared in the adult, and finally, nothing of the kind has been described for any other holothurian. When fully grown they measure about fifty mikrons in diam- eter and somewhat less in depth. They consist of very long, clear cells, with nuclei at the extreme distal ends, surrounding a more or less spacious lumen which opens to the exterior by a narrow canal of ordinary epithelial cells. Sometimes the clear cells stained lieavily, but often they did not stain at all. Up to this time the mesenchyme cells have played no part in the development of the larva. In Fig. 16, they are shown as they appear scattered almost uniformly through the segmentation cavity. Shortly after this, however, they begin to gather around the lower and outer edge of the water-vascular ring, and by the time the pentactula stage is reached they have begun the formation of the calcareous ring. Contrary to Semon's ('88) views on S. dig itata, and in accordance with Ludwig's ('91) observations on Cucumaria, I have found no evidence at all of any niesenchymatous musculature on the oesophagus. The first products of the mesenchyme cells to appear are five small straight rods between the primary tentacles but outside and somewhat below the hydrocoel ring. Soon after these, five more appear below the bases of the tentacles, so that there are now ten rods, five radial and five interradial, and they continue in this position so long as there are only five tentacles. I saw no evidence at all of any such shifting of position of the first five rods as Semon ('88) records for S. dig 'data, nor could I consider the position of the second series as agreeing at all with his description. Very soon after the appearance of the ten rods, they fork at the ends and begin to branch verj' irregularly. As will be seen from Fig. 46 a-i, the divisions occur at all sorts of angles and not only differ decidedly from Semon's figures of the same rods in ,S. digitata but show no sign at all of following his law ('87) for the formation of calcareous plates in Echinoderms. The much-branched ends of the rods come into very close contact but evidently never mingle, for the j^lates into. which they devetop are at all times easily separable and the line of division between them is practically straight. Very soon after the appearance of the first five calcareous rods, the radial nerves grow backward over them and before the completion of the pentac- tula, run to the posterior end of the animal. We have now reached the complete pentactula form, a slightly older stage of which appears in Fig. 18. The pentactula is about half a millimeter long and its characteristics 68 HT'BERT LYMAN CLARK OX may be briefly sumiiied up as follows: — Water- vascular system consisting of a closed hydrocoel ring or circumoral water-tube with five primary tentacles, between which are five very much smaller but equally erect secondary outgrowths; a water-tube in the mid- dorsal interradius connecting the circumoral rino; with the exterior; and a Polian vessel in the left dorsal interradius. Nervous system consisting of a circumoral ring ; five ten- tacle nerves on the inner face of the primary tentacles, the ectoderm of which is consid- erably thickened, especially on the outer side; five radial nerves bending backward over the secondary outgrowths of the water-ring and over the radial pieces of the calcareous ring, and running to the posterior end of the body; and five pairs of otocysts, lying external to the radial nerves, where they bend backward. Digestive system, consisting of a short oesophagus with the mouth opening anteriorly in the center of the circle of tentacles, a large stomach, a comparatively short intestine with a single loop in it, and usually an anus formed secondarily near or at the aboral pole. Digestive system attached to the wall throughout its whole course by a mesentery, formed by the union of the two walls of the right and left coelomic pouches. Calcareous ring consisting of five radial and five interradial pieces with much-branched ends. A few scattered glandular organs of doubtful function in various parts of the ectoderm. 7. The Development of the Adult Synapta. Since there is no cessation of growth nor any resting period on the assumption of the pentactula form, it is impossible to draw any hard and fast lines which will always serve to distinguish that stage. For many larvae, which appear to have only five tenta- cles, show on careful examination the rudiments of new ones, and other larvae which show no tentacles externally show the perfect pentactula form, when sectioned. As soon as the five primai-y tentacles have pushed out so far as to entirely obliterate the original opening of the atrium, the secondary outgrowths of the water-ring, which have hitherto scarcely shown any indication of growth, begin to develop and push upward. As we have already seen, the radial nerves lie directly over them, so that they cannot grow straight up but push out to one side or the other of the nerve. The outgrowth which lies in the mid-ventral radius, however, develops very slightly and does not -normally push out on either side of the nerve which overlies it. The outgrowths which lie in the right and left ventral radii take the opposite course, and broadening out laterally, grow up on both sides of the nerves which overlie them, to form accessory tentacles. The outgrowth of the right dorsal radius pushes out on the dorsal side of its overlying nerve and forms an accessory tentacle in the mid-dorsal interradius, while the outgrowth of the left dorsal SYNAPTA VIVIPARA. 69 radius shows as yet little tendency to develop either way (Fig. 85). Consequently we now have a larval form with ten tentacles, two in each interradius. As the accessory tentacles grow very rapidly they are soon equal in size to, and cannot be distinguished from, the five pi'iraary tentacles. It is hard to decide positively which of the five accessory tentacles develops first, for apparently they all begin to grow at about the same time. lu Chirodota rotlfera, Ludwig ('81) found the first two accessory tentacles in the lateral dorsal interradii, and he does not speak of finding any trace of additional tentacles in the other interradii. I have not found any stage similar to that in S. vivipara, and I think the five accessory tentacles appear at practically the same time. It is an important and interesting fact, however, that the five accessory tentacles are formed in precisely the same manner and from the same radii as the second series of five tentacles in Cucumaria, (Ludwig, '91). It seems to me that this fact proves satisfactorily that the radial canals in Synaptidae are homologous with those of the other holothurians or, more accurately, the secondary outgrowths of the hydrocoel ring in the Synaptidae are homologous with the five outgrowths of the hydrocoel ring in the true holothurians. In both cases, the ten-tentacled young has one primary and one accessory tentacle in each interradius. While this change is taking place in the number and arrangement of the tentacles, a cor- resjjonding change is going on in the calcareous ring. As the accessory tentacles push out into the interradii, the calcareous rod which lies at the base of the primary tentacle comes to lie between it and the acces.sory tentacle. I could not see that this came about by any actual movement of the rod itself, but was due simply to the increase of width in each interradius. In the further growth of the calcareous ring, the interradial pieces send up projections between the two tentacles (Fig. 46 h) and at the same time branch and divide so rapidly and irregularly that they soon become plates, with straight sides but pointed anteriorly and notched behind, made up of a very fine irregular network of calcareous strands (Fig. 44). The radial plates develop in the same way but send up two projections, one on each side of the radial nerve (Fig. 40 i). which finally fuse together above it and thus form the perforated plates of the ring (Fig. 4-3). About the same time, the mesenchyme cells lying between the ectoderm and the wall of the coelom begin to gather in groups close to the ectoderm and there give rise to anchors and anchor-plates so characteristic of the adult Synapta. The development of the cal- careous bodies from a straight rod takes place as described by Semon ('87) for Synapta inhaerans. While these deposits appear in the body-wall as far anteriorly as the base of the tentacles, in the walls of the latter, lying pai'allel to the long axis, tliere appear numerous rather long, more or less, knobbed rods (Fig. 48) similiar to tho.se described 70 HUBERT LYMAN CLARK OX by Seraon ('87) from the tentacles of various synaptids. These become very abundant in the older ten-tentacled larvae. The digestive tract meantime has increased in length, and the stomach is more clearly marked off from the intestine and oesophagus. The nervous system has not undergone any marked changes, but each of the accessory tentacles is supplied with a nerve on its inner side, as in the case of the primary tentacles. In various parts of the skin, especially anteriorly, clusters of ectoderm cells are to be found which later form the so-called sense-papillae (" Tastpapillen " of Hamann, '83). I have been unable to find any connection between these spots and the nerves until a very much later period, and I cannot decide how or when this connection is made. The glandular organs previously described are very abundant at this stage, especially posteriorly. Soon after the pentactula form is complete, the walls of the coelom and of the hydrocoel begin tlie formation of muscle fibers, always on the side turned from the cavity which they enclose. The first to appear are the longitudinal muscles of the tentacles and radii. The former appear as fibers on the outside of the tentacle canals and they soon form quite a thick layer. The radial muscles arise within a fold of the coelomic wall, which appears along the inner side of the radial nerves. This fold begins anteriorly near the calcareous ring and runs backwards with the nerve, enclosing a considerable space between its walls. In this space the muscle fibers arise from the eiidodermal cells of the coelom. Later on, the circular muscles of the body appear, arising from the outer side of the coelomic wall also. They cross the space in which the longitudinal muscles lie, forming a layer between the latter and the nerve. At the same time, the longitudinal and circular muscles of the digestive tract, and the muscles of the water-ring, begin to appear, so that by the time the ten-tentacled stage is reached, the musculature is practically that of the adult. With the appearance of the longitudinal muscles of the tentacles, comes the development of the valves at the openings of the tentacular canals, close to the upper edge of the calcareous ring. Before the accessory tentacles have begun to appear, there arises on the right hand side of the mesentery which fastens the intestine to the wall of the left interradius a longitudinal fold or evagination of the ei^ithelium close to the intestine (Fig. 58). This fold follows the coarse of the intestine, with the mesentery on the dorsal side, and grows forward along the stomach and backward toward the anus. Later a similar fold appears in the coelomic epithelium on the opposite (ventral) side of the digestive tract and the two folds soon become connected around the intestine and stomach by numerous ill-defined lacunae between the coelomic wall and that of the digestive organ itself. These vessels are the first stages of the blood vascular system and into them cells from SYXAPTA VIVIPARA. 7I the coeloinic epithelium pass to form the blood corpuscles. Theoretically the vessels ought to be lined with connective tissue of mesenchyme cells but these are so few in the early stages of the larva, that the connective tissue between the laminae of the mesen- teries or even around the digestive tract is very hard to demonstrate. The main blood vessels appear to be purely eutodermal in origin and their walls seem to be made up solely of the coelomic wall. At any rate, the dorsal vessel does not arise in S. vivipnra in the way given by Semon ('88) for its origin in *S'. dlgitata, by a simple split in the mesenchyme where the two coelomic folds unite above the intestine to form the mesentery. Very soon after the pentactula stage is reached the first rudiment of the genital system appears. It arises on the inner side of the right-hand lamina of the dorsal mesentery between the stoue-canal and the oesophagus. The first appearance is simply the increased size of the cells at this point, resulting in a thickening of the wall (Fig. 32), but the cells soon multiply rapidly and form a more or less spherical mass within the mesentery (Fig. 33). As this mass increases in size, cavities appear within it (Fig. 34) and these increase in size and begin to unite together until they form one central lumen for the gland (Fig. 35). Meanwhile the right lamina of the mesentery forms an outer epithelium which soon becomes quite distinct from the central mass of cells." Between this epithelium and the remainder of the gland a few mesenchyme cells form an extremely scanty connective-tissue layer. In the full-grown ten-tentaculed larva, the genital gland is plainly seen (Fig. 19), lying entirely on the right-hand side of the mesentery, near the stone-canal. The ten-teutacled larva (Fig. 19) is a more clearly defined stage in the development of Synapta vivij^iara than is the pentacula; that is, it seems to last longer, and the rela- tive condition of development of the various organs is more constant. The changes which occur subsequently in the assumption of the adult form must now be considered. The most obvious of these is the increase in the number of tentacles which arises from the addition of another tentacle to the right and left dorsal interradii (Fig. 86). The extra tentacle of the left side arises from the left dorsal " secondary outgrowth " of the hydrocoel ring, which has hitherto remained in its original position beneath the left dorsal nerve but now pushes out on its lower or venti'al side and forius the eleventh ten- tacle. At the same time, the extra tentacle of the right side arises from the lower or ventral side of the right dorsal " secondary outgrowth '' which pushes out on that side of the right dorsal nerve and forms the twelfth tentacle. Not infrequently individuals are found with thirteen tentacles, and in these the extra tentacle is usually in one of the ventral interradii. In such cases it is probable that the mid-ventral " secondary out- 72 HUBERT LYMAN CLARK ON growth" hiis ^rowii up on one side or the other of the mid-ventral nerve, although in normal s[)ecimen.s it dues not develop at all. Occasionally the extra tentacle is in the mid- dorsal interradius, and in such cases it is probable that the left dorsal " secondary outgrowth," which normally develops only a single tentacle, has given rise to a second on the dorsal side of the left dorsal nerve. Corresponding to these changes in the num- ber of tentacles additional plates appear in the calcareous ring, but these plates do not arise by interpolation of new rods. On the contrary, the plate of the same radius with the new tentacle increases its length and sends upward a new projection for the support of the tentacle (Fig. 47), and this subsequently forms the center of the new accessory plate. In specimens of the calcareous rings cleaned with caustic soda, it seemed to me that the calcareous plates of the right and left dorsal radii were less easily separated from those plates on their ventral side than from those on the dorsal, so I am inclined to think that for a time, if not throughout life, tliese two plates remain in closer union than any of the others. In specimens with thirteen tentacles, there is an additional plate in the calcareous ring corresponding to the extra tentacle. About this same time the miliary granules (Fig. 50) begin to appear in various parts of the body-wall and in the tentacles. Like all other calcareous concretions of Synapta, they are formed b}- mesench3nne cells. They usually appear in clusters of several hundred, which continue to increase in number afterwards until it may reach thousands. By the time twelve tentacles have appeared, the genital gland begins to push over on the left hand side, but it is not until long after the adult form is assumed in all other respects that the left branch of the gland equals the right in size. As soon as the left branch is well started, the germinal epithelium begins to push upward in the mesentery beside the stone-canal, and forms the genital duct, but does not reach the outer body-wall for some time. This account of the development of the genital duct accords with Mortensen's ('94) observations on Ciccumaria fjlackdis, although his account of the origin of the genital gland itself differs considerably from my observations. Important changes are going on meanwhile in the nervous system. From the inner side of the circumoral ring nerves or bands of nervous tissue arise and pass inward to the oesophagus. These will be referred to more fully in describing the nervous system of the adult. Even in the ten-tentacled stage, before the remaining two tentacles have made a fair start, there arises on each side of the tentacle nerve at its base a knob- like outgrowth which becomes covered over with a peculiar mesenchyme layer, and these form the " eyes," which also appear at the base of the eleventh and twelfth tentacles, after they receive their nerves from the circumoral ring. With the appearance of these eyes, the first trace of pigment appears in the mesenchyme not only about them but in various parts of the body, especially around the calcareous ring. This pigment on its SYNAPTA VIVIPARA. 73 first appearance is bright green, even about the eyes, so tliat at this stage the eyes of tlie young Synapta are very conspicuous as large green spots at the base of the tentacles. Very soon, however, a dark reddish brown pigment appears, but this is probably an older stage of the green, and not a different pigment; for the pigment around the eyes soon loses its green color and turns brown, and there is no reason to assume that the pigment in other parts of the body is any different from that around the eyes. All of the pigment arises in the connective tissue, and is apparently a product of the mesenchyme cells. It is especially abundant at the anterior end of the body, and above all other places in and around the calcareous ring. Before the number of tentacles is complete the ciliated funnels so characteristic of Synapta begin to appear on the mesentery, near the body-wall. These funnels arise from a large cell or group of cells in the endodermal epithelium of the mesentery (Figs. 01 and 62a). The multiplication of these cells soon forms a hemispherical outgrowth (Fig. (J2d) which increases in size and becomes more and more spherical in shape, until it is finally attached to the mesentery by only a narrow stalk (Fig. 62e)., It then begins to flatten on one side, and the cells of its outer layers become smaller and stain moi'e heavily than those nearer the stalk (Fig. 62f). The flattened surface at last becomes concave and the funnel shape begins to be assumed. At the same time, the stalk becomes elongated and draws up within it some of the connective-tissue layer of the mesentery, which becomes the supporting layer of tlie funnel. Even during the ten- tentacled stage the digits of the tentacles begin to be formed, but they do not become prominent until the twelve tentacles are all developed. The digits arise as evaginations of the water-canal of the tentacle (Fig. 56) which very soon become shut off" from the main canal and in the adult have no connection with it (Fig. 55). The earliest ones to appear are near the middle of the tentacle, and the later ones appear both proximally and distally to them. The digits form longitudinal muscles on the outer side of the central cavity in the same waj- as the tentacles themselves. They are also supplied with nerves from the main tentacle nerve. The peculiar glandular organs of the larva are no longer forming but seem rather to be disappearing, and tlie longitudinal rods of the tentacles reach their maximum number at this time. The circumoral sinus, which was entirely cut off from the rest of the coelom in the pentactula stage, has increased greatly in size (Fig. 89) but is now in open communication with the body-cavity, though strands of connective tissue traverse it, uniting the oesophagus to the water-ring and, higlier up, to the coelomic wall. With the greatly increased size of the 3"oung Synapta, comes a considerable change in the relative position of the organs in the body-cavity. The body has grown much posteriorly, drawing out with it that part of the intestine which lies in 74 HUBERT LYMAN CLARK OX the right ventral interradius. The nerve rin^ is drawn upwai'd with the growth of tlie tentacles, so that it coines to lie very near tlie ectoderm at their base. The increased length of the tentacular canals has pushed the water-ring downward so that it lies some distance below the calcareous ring (Figs. 90 and 91), but it is still in open communica- tion with the exterior by means of the water-canal (Fig. 66). Mesenchyme cells have formed a few calcareous rods about the latter (Fig. 49), especially near the point where it passes into the body-wall. Just within the body-cavity from this point, openings have appeared on it which place its interior in direct communication with the body-cavity, so that the water-vascular system combines the primitive external opening of the pentactula with the internal madreporitic openings of the other holothnrians. The mesenchyme cells around the calcareous ring have formed on its posterior edge a connective-tissue ring, which later becomes so prominent in the adult as the cartilaginous ring. In concluding this account of the embryology it may be well to summarize briefly the derivation of the different organs from the germ layers of the gastrula. Ectoderm. From the gastrula-ectoderm arise the ectoderm of the adult, the sensory epithelium of the tentacles, the entire nervous system including all the sense organs, the larval glandular organs, and a small part of the oesophagus. Possibly the extreme posterior part of the rectum is also ectodermal. Endoderm. From the gastrula-endoderm arise first of all the scattered mesenchyme cells which make up the mesoderm. Soon afterwards the hydroenterocoel is divided off. The remainder of the archenteron forms simply the lining of the digestive tract, including most of the oesophagus. From the hydroenterocoel, the coelomic ^^ouches are constricted off, leaving behind the hydrocoel, from which the entire water- vascular system, and also the cavities of the digits, arise. The longitudinal muscles of the tentacles and digits come from the epithelium of the hydrocoel. The coelomic pouches form the peritoneal lining of the body-cavity and the epithelial covering for the various organs contained in it. All the muscles of the body-wall, gut, genital glands, water-ring, and Polian vessels are also derivatives of the endoderm. The genital organ, including the genital duct, nnd the ciliated funnels are likewise derived from the wall of the coelom. The haemal system is also covered by the epithelium of the coelom and apparently arises as evaginations of the same, while the blood-corpuscles certainly come from that layer. .Mesoderm. From the mesenchyme cells, arising from the archenteron of the gastrula, come all the connective tissue of the body, the pigment, the covering of the eyes, all the calcareous concretions (including the calcareous ring), and the cartilaginous SYNAPTA VIVTPARA. 75 ring. No trace of mesenchymatous musculature was found anywhere, and the part which the mesoderm takes in tlie formation of the haemal system is certainly incon- siderable. 8. The Anatomy of the Adult. Although the anatomy of the European Synaptas is so well known, thanks to the investigations of Baur ('64), Semon ('87), Hamann ('83 and '89), Cuenot ('91), and others, there are so many points in which Synapta vivvpara differs from the forms hitherto examined, it seems desirable to add a few words concerning these and other points. Except in the case of sense-organs, no attempt has been made to go into the histology, but my attention has been confined to the more general features of the minute anatomy. In the structure of the body-wall and the muscular system, there are no important features to mention, aside from the shape of the longitudinal radial muscle bands. Each of these bands is forked at its anterior extremity, and the two branches are attached to the radial calcareous plate, one on each side of the radial nerve. These branches soon unite as they pass backward, and form a single narrow band, which extends far out into the body-cavity. But still further back, it decreases in depth and increases correspondingly in width, and the e^iithelium which covers it tends to fuse at the outer edges with the epithelium of the body-cavity, so that at numerous points in its coui'se the muscle has acquired secondary attachments to the body-wall. During the greater part of its course, it is a nearly flat band, but as it approaches the extreme posterior region of the body, it tends to become cylindrical, and where it ends near the anus the cross-section is circular. These changes in shape will be made clear from Figs. 94-100. The structure of the genital glands has already been given in detail, and the openings in the wall of the rectum have also been sufficiently described. The blood- vascular or haemal system is very simple, consisting of a dorsal and ventral vessel on the intestine and stomach with connecting lacunae in their walls. Posteriorly, both vessels end about half way down that section of the intestine which lies in the right ventral interradius (Fig. 92). Auteiiorly, the ventral vessel ends a little in front of the stomach, on the oesophagus. The dorsal vessel runs forward to the water-ring and forms on its inner side a circumoesophageal ring, from which branches pass on to each tentacular vessel. The dorsal blood-vessel also seems to open out in the mesentery to form broad lacunae about the genital gland, such as Cuenot ('91) found in European Synaptas, but I never found coagulated blood there as in the dorsal vessel, and I do not feel sure that 76 HUBERT LYMAN CLARK ON such lacunae actually exist. The ventral vessel of the stomach does not lie appressed to its wall, but entirely free from it and connected with it by several small branches. It is also connected by a large transverse vessel with the ventral vessel of the intestine (Fig. 92), and the two sections of the latter are also connected by a similar vessel. These transverse vessels do not appear until the animal is several centimeters long, when they arise by outgrowths of the coelomic epithelium of stomach and intestine wbich, lying close together as they do in the loops of the digestive tract, touch and fuse (Figs. 59 and 60) and with the increased growth of the intestine are finally drawn out to slender con- necting vessels. Like the vessels of the young Synapta, these are supposed to be lined witli connective tissue, but I have been unable to detect it in their walls. The ciliated funnels of Synapta vivipara differ considerably in appearance from those of S. digitata or ;S'. inhaerans, though they do not differ essentially in structure. Only one sort seems to be present and these are quite small but extremely numerous on all three of the mesenteries. They measure from iOfx to 75/i in length, and fiom 30/li to 40/* in breadth and depth, which is only about half the size of tliose of S. digitata. They are broad funnel- or cornucopia-shaped in outline and usually have a short stalk. Their general structure will be easily understood from Figs. 63-65. The water-vascular system consists of a circumoesophageal ring from which canals arise and pass to the ten- tacles, into which their entrance is guarded by well-developed valves. Each tentacle rests on the calcareous ring in such a way that the outer half of the base is on the out- side of the calcareous plate, forming a sort of rudimentary ampulla (Fig. 90). There is not in the adult, any more than in any of the larval stages, the slightest trace of radia. water-canals. Dependent from the ring-canal there is always present in the left dorsal interradius a slender Polian vessel five or six millimeters long, and in nearly all adults additional Polian vessels, sometimes as many as six, are present in the ventral interradii. The stone-canal leaves the water-ring on the left-hand side of the mid-doi'sal interradius and does not lie in the dorsal mesentery but clearly separate from, and to the left of it. It soon passes into it, however, on its outward course and runs to the body-wall close beside the genital duct (Figs. 66 and 67). It enters the body-wall on the right of the mesentery and bends upward more or less abruptly, opening finally to the exterior close behind the circle of tentacles (Figs. 66-70). In exceptional cases there are two open- ings (Figs. 71-73) or rarely the reverse happens and the canal closes before the exterior is reached. Besides this external opening, the stone-canal also opens into the body-cavity through a well-developed madrepore (Figs. 66 and 74). Throughout its course the canal is heavily ciliated, and especially so around these madreporitic openings, the whole arrangement being admirably adapted for keeping the body-cavity fluid well aerated. SYNAPTA VIVIPARA. 77 Tlie nervous system consists as in all Synaptidae of the central circumoral ring with the five radial branches and the smaller branches to each of the tentacles, but there are some additional nerves and certain of the sense-organs which have not been figured hitherto. Each of the radial nerves is divided longitudinally into an outer and an inner band as in other Synaptas, but, unlike them, there are no canals or vessels of any kind accompanying the nerves. There are, therefore, in the radii of S. vivqMra, no spaces or lacunae in connection with either the blood, water, or nervous systems, but they are marked simply by the longitudinal muscles and nerves (Fig. 99). Each tentacle-nerve sends off branches to the digits (Fig. 55), so that almost the whole surface of the tentacle becomes sensory. On the base of the tentacles and in various parts of the ectoderm all over the body, there are numerous sense-buds or " taste-papillae," (Fig. 84), such as were first described by Haniaini ('88). The structure of these organs has been well described by him and still more recently by Cuenot ('91). My observations support the opinion of the latter, that under each one of these sense papillae there lies a small ganglion. From the lower side of the circumoral ring, there arises between every two tentacles a broad band-like nerve (Figs. 75 and 76) which runs inwards towards the mouth, innervating the ectoderm of the oral disc as well as the muscles of the oesophagus. Hamann ('83) describes a single nerve to the oesophagus, and Semon ('88) speaks of it in S. digitata, but so far as I can learn no other nerves from the inner side of the ring have been described in holothurians. At the base of each tentacle, there are easily seen a pair of reddish brown spots, the so- called eyes (Figs. 77 and 78). Similar spots are mentioned in various Synaptas by Miiller ('50), Baur ('64), and Semper ('68), but Semon ('87) and Hamann ('84) seem to doubt their visual function. There can be little doubt, however, that in Synapta vioipara these eyes are actually of service as light-detecting organs. In position and general structure they resemble those described by Ludwig and Barthels ('91) for S)/7ia2Jta vittata. They consist of a distinct, rather horny mesodermal layer, of a light Ijrown color, containing scattered nuclei, overlying the swollen end of a large nerve which arises on each side from the base of the tentacle-nerve (Fig. 77). The ends of these nerves are made up of large nerve-cells with large nuclei, which are somewhat swollen and apparently vacuolated at their outer extremities. They are polygonal in outline, when seen in cross-section (Fig. 79), and the inner ends taper off into fibers which run out into the nerve (Fig. 80). The mesodermal covering, which also has the appearance of being vacuolated, is clearly a continuation of the thin mesoderm layer which surrounds all the nerves. The eyes are about OO^u, in diameter, the mesodermal covering being six or eight mikrons thick. That this covering may be affected by light is probable, for its color is due to the pigment it contains. The other noteworthy sense-organs are the otocysta & 78 HUBERT LYMAN CLAliK OX (Figs. 81-83), already mentioned as lying external to the radial nerves at the point where they bend backwards over the calcareous ring. They are much smaller than those figured by Cuenot ('91) for S. inhaerans and differ from them in having only a single large vesiculated cell enclosed within them, instead of a number of small ones. The otoc3'sts of S. vivipara measure only about 60-70^ in diameter, while the contained cell is almost a quarter as large. In no case have I found more than one cell enclosed in an otocyst of this species. Hamann ('84) suspected that they were larval organs having no function in the adult, but Semon ('87) has already proved that idea erroneous, as Hamann ('89, p. 308) has since admitted. If any further evidence were needed, it could be found in the increase of size of the organs during the development of the animal (Figs. 81-83) as well as in the very obvious connection with the radial nerves. But I am inclined to the view that these so-called otocysts do not function as hearing organs at all, but are of use to indicate the animal's position. Semon ('87) was unable to find any cilia in them, and his experiments on living Synaptas brought him to the conclusion that they were deaf to sound waves. If the enclosed cell is vesiculated, as it appears to be, it must float in the fluid with which the otocyst is filled and so presses on that part of the wall which is uppermost. Any change in the position of the animal would cause a corresponding change in the position of the enclosed cell and thus give rise to a changed sensation. The fully grown Si/naj)ta vivipara (Fig. 20) measures from ten to fifteen centi- meters in length and from four to nine millimeters in thickness ; the size depending largely on the state of contraction of the muscles. In color they vary from a pale reddish brown to a very dark greenish brown more or less spotted and blotched with white. The ground color is due to the pigment in the connective tissue of the body-wall and varies greatly with the amount of that pigment, but the white spots and blotches are due to the aggregation of great numbers of the miliary granules, just beneath the ectoderm. The pigment is not affected to any extent by pui-e alcohol, but corrosive sublimate and all acids destroy or greatly modify it. Just posterior to the calcareous ring and in connection with it there is a ring of cartilage-like connective tissue (Fig. 90). This structure was described and figured by Theel ('86), who also figured the anchors and plates from the body-wall, in his account of S. plcta. The anchors (Fig. 51) lie close under the ectoderm and parallel with it, at right angles to the main axis of the body. Each anchor is much curved or bowed inwards, while its arms or flukes are curved outward so that the points of the arms are always projecting. The vertex is not toothed but has five or six almost spherical knobs on its edge. The posterior end is broadened out into several short, very finely-toothed branches. Beneath the anchors lie tlie rounded, smooth-edged, somewhat arched plates, which normally possess seven large toothed holes SYNAPTA VIVIl'ARA. 79 (Fig. 52) and two large and three small smooth holes. On the side of the plate next to the anchor and near the posterior end is an arched bow, which bears a few teeth on its anterior edge. Increased growth of the plate often increases the number of holes (Fig. 53), but as a rule they are very constant. The calcareous rods which were so abundant in the tentacles of the young larvae are so few that for a long time I was led to consider them entirely wanting. The tentacles (Fig. 57) of the adults are long and slender with from 12 to 18 pairs of digits, but the number varies greatly with the age and size of the animal. The glandular organs which characterize the young ten- tentacled stage seem to be entirely wanting now ; at any rate, I have never found any trace of them in an adult. A number of interesting monstrosities were found, chiefly among the older embryos. One of these is shown in Fig. 93, but some of the others were much more complicated, consisting of three, four, and, in one case, five young, which had grown together, or budded from each other in various ways. Among adults, besides the rather common addition of an extra tentacle, the only peculiar specimen found was one which had only three radial muscles and nerves and only eleven tentacles. There were three tentacles in the mid-dorsal interradius (indicated by the mesentery), and four tentacles in each of the lateral interradii. 9. Conclusions. Probably no theory of echinoderm phylogeny has attracted more attention or seems more jilausible than that upon which Semon ('88) determined, as the result of his studies on the development of the auricularia larva of Synapta digitata. Although it still finds supporters at the present time, the investigations of Ludwig ('91) on Cucu- maria and of Ludwig and Barthels ('91) on the anatomy of the Synaptidae have shown the incorrectness of Semon's views, while the observations of Bury ('89 and '95) have cast doubt on his interpretation of some of the conditions in auricularia. It is not my inten- tion to enter here into any discussion of the phylogeny of the echinoderms but only to suggest some of the points in the phylogeny of the holothurians, upon which the history of Synapta vmipara seems to tlirow some light, and to indicate some of the particulars in which my studies have apparently offered support to Bury's ('95) theory of the ances- tral form of the echinoderms. There are three possible opinions concerning the relationship of the Synaptidae to the other holothurians : first, Semon's ('88) view that Synapta represents a primitive form, from which the other holothurians have been derived; second, Cuenot's ('91) view 80 HUBERT LYMAN CLARK ON that the Synaptas represent a more primitive branch of the echinoderms than and dif- ferent from the true holothurians ; third, Ludwig's ('89-'92) view that the Synaptidae are degenerate, pedate holothurians. Semon bases his opinion on the high development of the nervous system in Synapta, the absence of anything in their manner of life to cause degeneration, and the fact that no organs appear in the development of the young Synapta which are not present in the adult. His own observations on the nervous sys- tem of Synaptas as well as Hamann's ('88) and Cuenot's ('91) show that there is some tendency to diversity in the nervous system, especially as regards sense-organs, among the SynaptidaC; and it also shows a considerable degree of adaptability to changing conditions. Moreover, I liave found in S. vlvlpara that the sense-organs are highly developed, and there are additional nerves to the oesophagus, indicating modifications to suit the mode of life. It seems from these facts, that too much stress must not be placed on the opinion that the nervous system of Synapta digltata is primitive. As regards degeneracy and the absence of anything in the mode of life to cause it in Synaptas, it seems that Semon has expressed an erroneous opinion of the causes of defeneration. He says that we know of only three reasons for its occurrence, parasitic, fixed, or subterranean life, and, since none of these are characteristic of Synaptas, they cannot be degenerate. Had he given the matter more careful consideration he would have seen how untenable his position is. Certainly no one will deny that the loss of the power of flight in certain birds, as the famous New Zealand ground parrot, is degenera- tion, yet they are neither parasitic, fixed, nor subterranean. Any change in the mode of life, due to a change in environment, may result in degeneracy. The word has come to have a bad significance so that we think of it as indicating that the animal is on the down-hill road, whereas it strictly means that the animal has lost some organ or group of organs which its ancestors possessed and so has become less complex than they. Such a loss must necessarily, however, always be a gain to the species involved, otherwise it could never have come about. Now, it is entirely conceivable that in certain conditions of life on the ocean bottom, in shallow water near shore, the loss of numerous ambulacral appendages and the concentration of the water-vascular system in the circumoral ten- tacles would be a distinct advantage to the animal. Such has certainly been the case in Caudina (Gerould, '96), for instance, and it is probably true of all the Molpadiidae, although in these cases it may have been brought about by subterranean life. But Semon has by no means proved his point that the Synaptas are not, as a rule, subterranean. Whatever may be the condition at Naples, both on the New England coast and in Jamaica Synapta inhaerans and its allied forms are found normally buried deep in the sand, while the large Synaptas, like S. lappa, are found under stones, which is practically a sub- SYNAPTA VIVIPARA. 81 terranean mode of life. The absence of anything, therefore, in their manner of life to cause degeneration is by no means proven and will hardly stand as a good test for con- sidering the Synaptas primitive. The statement that there is no structure developed in the young Synapta which does not appear in the adult is completely refuted by the careful observations of Ludwig and Barthels ('91) on the absence of radial water-canals in the Synaptidae. Since all observers are agreed that radial canals are developed in the embryo of S. difjitata, it is clear that we have here a most important structure lost in the adult. .For these reasons, it seems to me that Semon's view is no longer tenable. Cuenot's ('91) view is based chiefly on the important differences in the embryology of the Synaptidae and that of otlier holothurians, but it seems to tne that he does not take suffi- cient account of the important evidences of degeneration in the Synaptas. Ludwig's ('89-92) view appears to be the one best supported by the facts, and the anatomy and embryology of >S'. vivlpara offer no little confirmatorj^ evidence. If we compare its ten-tentacled stage with the hypothetical ancestor which Ludwig describes for the Synaptidae, the resemblance is extraordinary, almost the only important differ- ence being that the genital gland in S. vimpara is not equally developed on each side. In fact, the ten-tentacled stage of Syiicqjta v'tvipara represents an actual step in the development of the Synaptidae from Ludwig's hypothetical ancestor. The Jamaican species is bej'ond doubt a highly modified form, and, though in some respects more highly organized than other Synaptas, in certain particulars, degeneration has gone further. Differing from other holothurians in its manner of life and its mode of reproduction, it has undergone various modifications to fit it for the changed conditions. Living in sea- weed near the surface of the water, it has developed pigment in its skin to a marked degree, and at the same time has acquired additional sense-organs in the eyes at the base of the tentacles, and an increased innervation of the oral disc. In conformity to its changed mode of reproduction, important changes have taken place in the structure of the genital gland, openings have appeared in the walls of the rectum to connect the body- cavity with the exterior, while the stone-canal has retained or has acquired secondarily its original connection with the exterior. During the progress of these specializations, the same causes have led to degeneration in other particulars. The changed mode of reproduction has modified the genital duct, so that its lumen is no longer open to the ova, and it no longer has an obvious opening to the exterior. The changed mode of life has caused a greater concentration of the water-vascular system around the mouth and a consequent further degeneration of the radial canals, so that they no longer appear as such even in the embryology, but tentacles develop directly from the secondary out- growths of the hydrocoel. And, furthermore, the mid-ventral outgrowth has degenerated 82 HUBERT LYMAN CLARK ON a step further and normally never develops at all, but disappears altogether, which is especially interesting as the mid-ventral radius is the first to develop its nerve and oto- cysts, and so seems to be the leader in modifications. The manner of life has also caused a modification of the tentacles in a way which we may consider as a degeneration from other Synaptas. Semon ('87) describes calcareous rods in the tentacles of all the Medi- terranean Synaptas, and these appear abundantly, as we have seen, in the young stages of S. vivipara, but in the adult they seem to have almost entirely disappeared, the tentacles and digits being very delicate and flexible and containing no calcareous deposits,, except some miliary granviles. The changes in the larva due to the retention and development of the ova in the body-cavity of the mother, such as closing of the blastopore and absence of any true metamorphosis, must also be taken into consideration. For these reasons, we must consider >S'. vivipara as a highly specialized Synapta, but in its water-vascular system it has degenerated a step further than S. digltafa, although it is neither "parasitic, fixed, nor subterranean " in its manner of life. It is very clear from the examination of the literature on the subject that the study of any one form or class of echinoderms is entirely insufficient to fit one to determine on a theory of the phylogeny of the group. Notable examples of this may be seen in the speculations of Semon ('88), Blitschli ('92), and MacBride ('96). The facts added to our knowledge of eehinoderm embryology by all these writers are of real value, but their hypotheses are for the most part of little importance. The same may be said of any attempt to determine the entire course of eehinoderm evolution by the study of palaeon- tology alone, a notable example of which has recently appeared by no less an authority than Haeckel ('96). The only author who has carried on original investigations on all the classes of echinoderms and has formulated his views on the phylogeny of the group is Bury ('80 and '95), and I cannot conclude this paper without calling attention to the support which my observations give to him, on the questions involved in the development of the Synaptidae. Regarding all the points on which he lays particular stress, I have confirmed his work completely or in part. The adradial position of the water-tube, the rudimentary left anterior enterocoel, and the growth of the left body-cavity around the oesophagus are all very clearly marked in the development of Synapta vivipara. The only point on which I could not entirely confirm his views was on the formation of the mesentery of the stone-canal from the left coelom entirely, and on this point what evi- dence I did obtain indicates the correctness of his position. SYNAPTA VIVIPARA. 83 10. Literature. [Articles marked * contain references to Synapta vivipara.] Agassiz, A. '64. On the embryology of echinoderms. Mem. Amer. acad. arts and sci., Vol. 9, p. 1-30. Baur, A. '64. Beitrage zur naturgeschichte der Synapta digitata. Nova acta acad. Leop.-Carol., Bd. :'l, 110 pp., 8 taf. *Bronn, H. G. '60. Die klassen nnd ordnungen der strahlentliiere (Actinozoa). Bronn's Kla.sseii und ordnnngen des thierreichs- Leipzig nnd Heidelberg, 4:U pp., 48 taf. Biitscldi, O. '92. Versuch der ableitnng des echinoderias aus einer bilateralen nrforra. Zeitschr. f. wi.ss. zuol., Bd. 53, suppl., p. 136- 160, taf. 9. Bnry, H. '89. Studies in the embi7ology of echinoderms. Qnart. journ. micros, sci., Vol. 20, p. 409-449, pis. 37-39. Bury, H. '95. The metamorphosis of echinoderms. Qnart. journ. micros, sci., Vol. 38, p. 45-135, pis. 3-9. » Clark, H. L. '90. The viviparous Synapta of the West Indie.s. Zool. anz., Bd. 19, p. .398-400. Cufinot, L. '91. Etudes morphologiques sur le.s echinodermes. Arch, de biol., Tom. 11, p. 313-880, pis. 24-31. .See also Arch. zool. expfr., (2), Tom. 9, Notes et Rev., p. 8-lC. Danielssen, D. C, and Koren, J. '82. Holothurioidea. Norvpegian North Atlantic Expedition, 1876-'"8. 6. Zoology. Christiania, 94 pp., 13 pis., 1 map. Gerould, J. H. '96. The anatomy and histology of Caudina arenata Gould. Proc. Best. soc. nat. hist.. Vol. 27, p. 7-74, 8 pis. Also Bull. nnis. comp. zoOl., Vol. 20, p. 121-190, 8 pis. Goette, A. '80. Bemerkungen zur entwickelungsgeschichte der echinodermen. Zool. anz., Jahrg. 3, p. 324-320. Haeckel, E. '96. Die amphorideen und cystoideen. Beitrilge zur morphologie uud phylogenie der echinodermen. Festschrift zura siebenzigsten geburtstage von Carl Gegenbaur, 15d. 1, p. 1-170, 4 taf. Hamann, O. '83. Beitrage zur histologie der echinodermen. 1. Die hohithurien (Pedata) und das nervensystem der asteriden. Zeitschr. f. wiss. zool., Bd. 39, p. 14.5-190, taf. 10-12. Hamann, 0. '84. Beitrage zur histologie der echinodermen. Heft 1, Die holothurien. .lena, 100 pp.. 6 taf. Hamann, 0. '89. Anatomie der ophiuren nnd crinoiden. .Tena. zeitschr., Bd. 23, p. 233-388, taf. 12-23. H6rouard, E. '80. Recherches sur les holothuries des cotes de France. Arch. zool. expfer., (2), Tom. 7, p. 53-5-704, pis. 2.5-32. .lourdan, E. '83. Recherches sur I'histologie des holothuries. Ann. mus. hist, nat. Marseille. Zool., Tom. 1, Mem. 6, 04 pp., pis. 1-5. Kovpalevsky, A. '67. Beitrage zur entwickelungsgeschichte der holothurien. Mfm. acad. sci. St. Petersbourg (7), Tom. 11,8 pp., 1 pi. * Lampert, K. '85. Die seewalzen. Reisen in Archipel der Philippinen. Von Dr. C. .Semper, Bd. 4, Heft 3, 312 pp., pi. 1. Wie.sbaden. * Ludvpig, H. '81. Ueber eine lebendiggebarende synaptide und zwei andere nene holothurienarten der brazilianischen kiiste. Arch. de biol., Tom. 2, p. 41-58, pi 3. * Ludwig, H. '86. Die von G. Chierchia auf der fahrt der Kgl. Ital. Corvette " Vettor Pisani " gesammelten holothurien. Zool. jahr- bucher, Bd. 2, p. 1-36, taf. 1-2. 84 HUBERT LYMAN CLARK ON * Ludwig, H. '89-92. Echinoilermeii. Broiins Klassen uiiJ unluungen des thierreichs, Bd. 2, Abth. 3. Lieferungen 1-10 (Holo- thurien). Luilwig, 11. '91. Zur eutwickeluiig.sge.schichte der holothurien. Sitzungsber. k. Preuss. akad. wiss., No 10, p. 179-192, No. 32, p. 603- 612. Transl. in Ann. and mag. nat. hist., ((!), Vol. 8, p. 413-427. * Ludwig, H., und Barthels, P. '91. Zur anatomie der synaptiden. Zool. anz., .lahrg. 14, p. 1 17-119. MacBride, E. W. '96. The development of Asterina gibbosa. Quart, journ. miero.s. .sci.. Vol. 38, p. .339-411, pis. 18-29. Metschnikoff, E. '()9. Studieu liber die entwickelnng der eeliinodei iiu'U und neniertinen. .Mfm. acad. .sci. St. Pttersbourg, (7), Tom. 14, 73 pp., 12 pis. Mortensen, T. '94. Zur anatomie und entwieklnng der Cucumaria glacialis ('Ljnngman). Zeitschr. f. wiss. zool., Bd. 57, p. 704-732. taf. 31-32. MUUer, J. '50. Anatoniische sludien iiber echinodernien. Miiller's arehiv, Jahrg. 1850, p. 117-155. Miiller, J. '52. Ueber Synapta digitata nnd iiber die erzengung von schnecken in holothurien. Berlin, 18-52, 30 pp., 10 taf. ('irsted, A. S. '49. [Slaegt of Synapta grnppen.] ^■idens. medd. nat. for. Kjobenhavn, Aarene 1849 og 1860, p. vii. Translnteil in Ludwig ('81), p. 48. Quatrefages, A. de. "42. Memoirs sur la synapte de Duvernoy (S. duvernaea A de Q). Ann. .sci. n.at , Zool., (2), Tom. 17, p. 19-93, pi. 2-5. Selenka, E. '67. Beitrilge zur anatomie und systematik der holothurien. Zeitschr f. wiss. zool., Bd. 17, p. 291-372. taf. 17-20 Selenka, E. '76. Zur entwickelung der holothurien (llolothuria tubulosa n. Cucumaria doliolum). Zeitschr. f. wiss. zool., Bd. 27, p. 166-178. gelenka, E. '83. Die keimbliltter der ecliinodermen. Studien ueber entwickelungsgeschichte der thiere. Heft 2, p. 28-61, 6 taf. Wiesbaden. Semon, K. '83. Das nerven.sy.stem der holothurien. Jena, zeitschr., Rd. 16, p. 1-23, taf. 1-2. Semon, R. '87. Beitrage zur naturgeschichte der synaptiden des Mittelmeeres. Mittheil. zool. station Neapel, Bd. 7, p 272-300; p. 401-422, taf. 9, 10, u. 15. Semon, R. '88. Die entwickelung der Synapta digitata und die stammesgeschichte der eohinodermen. Jena, zeitschr., Bd. 22, p. 17.5- 309, taf. 6-12. Semon, R. '89. Die homologien innerhalb des echinodermenstammes. Morph. jahrb., Bd. 15, p. 253-307. Semper, C. '68. Reisen im Archipel der I'hilippinen. 2. Wissenschaftliche resultate. 1. Holothurien, 288 pp., 40 taf. Leipzig. Th6el, H. '82. Report on the Holothuroidea. Pt. 1. ''Challenger" Reports. Zoology, Vol. 14, Part 13, London. Th6el, H. '86. Report on the Holotliuroidea. Pt. 2. " Challenger " Reports. Zoology, Vol. 14, Part 39. London. Thomson, W. '62. On the development of Synapta inhaeren.s, O. F. Miiller (sp.). Quart, journ. micros, sci., Vol. 2, j). 131-146. SYNAPTA VIVIPARA. 85 n. Explanation of Plates. [All figures excejit 20 and 2y were drawn witli the aid of a camera Incida.] ABBREVIATIONS USED. A. — atrium. LGO, AE. — anterior enterocoel. LM. • AN. — anus. M. — AO. — atrial opening. Mes. ■ AT. — accessory tentacle. MD. BC. — body-cavity. MY. - BL. — blastopore. NR. - BV. — blood-vessel. 0. — CF. — ciliated funnels. OE. - CH. — circumoesophageal ring of blood-system. OEN CM. — circular muscles of body-wall. FT. CR. — calcareous ring. PV. CT. — connective tissue. R. — Car.R. — cartilaginous ring. RC. Cir.S. — circular sinus formed from the anterior-pmlon- RN. gallon of the left coeloni. SC. DV. — dorsal vein of blood-system.. SO. ■ E. — enterocoel. SI*. Ect. — ectoderm. T. — Epi. — epithelium. TC- Ey. — eyes. TN. - GD. — genital duct. TV. - GG. — genital gland. V. — H. — hydroooel. WP. - I. — intestine. WR. LC. — left coelom. . — larval glandular organ. — longitudinal nuiscles. mouth. — mesenchyme. — madrepore. — mesentery. — circumoral nerve-ring, otocysts. — oesophagus. . — nerve-band to mouth and oesophagus. — primary tentacle. — Polian vesicle. rectum. — right coelom. — radial nerve. — stone-canal. — secondary outgrowth of tlie hydrocoel. — sense-papilla, tentacle, -canal of tentacle. — tentacle-nerve. — blood-vessel on inner side of tentacular canal, valves. — water-pore. — water-ring. 86 HUBERT LYMAN CLARK ON PLATE 11. Fig. 1. Mature ovum. 22.5x. Fig. 2. Two-cell stage of segmenting egg. 225x. Fig. 3. Four-cell stage. 225x. Fig. 4. Eight-cell stage. 225x. Fig. 5. Sixteen-cell stage. 225x. Fig. fi. Thirty-two-cell stage, seen from the side. 225x. Fig. 7. Tliirty-two-cell stage, seen from one of the poles. 225x. Fig. 8. Blastula, seen from the side. 225x. Fig. !l. Gastrula, seen from the side. 22.5x. Fig. 10. Older gastrula, seen from left-hand side, to show formation of the water-pore. Fig. 11. Still older stage, seen trom left-liand side, to show the drawing away of the archenterou from tlie water- pore. 225x. Fig. 12. Slightly older stage, seen from left side, to show the formation of the mouth. 22ox. Fig. 13. Older stage, seen from in front (ventrally), to show the formation of the enterocoel. 22.5x. Fig. 14. Older stage, seen from in front (ventrally), to show the formation of the coelomic vesicles. 225x. Fig. 1-5. Older stage, seen from in front { ventrally), to show the five primary outgrowths of the hydrocoel. 22ox. Fig. 16. Older stage, seen from left side, to show the hydrocoel, body-cavities, and atrium. 225x. Fig. 17. Very young pentactula, from right side, to show the nerves and sense-orgaus. 22-5 x. Fig. 18. Older pentactula, seen from dorsal surface, to show the radial nerves, calcareous ring, and rudiment of accessory tentacle. 130x. Fig. 19. Ten-teutacled young, seen from right side, to show genital gland and arrangement of organs. Twelfth tentacle just developing. 22x. Fig. 20. Adult Synapla vivlpara, seen from ventral surface. Xat. size. PLATE 12. Fig. 21. Vertical section of gastrula, to show the thickened ectoderm at apical pole. 225x. Fig. 22. Transverse section of Fig. 13, at the line A. B., to show the tliickeued ventral ectoderm. 225x. Fig. 23. Schematic outline of hydrocoel, to show the position of water-canal. Fig, 24. Transverse sections of hydrocoels of three embryos, to show formation of anterior enterocoel. y emln-y- ologists, later or post-embryonic stages, on which Professor Agassiz laid especial stress, have been generally overlooked. It is for the most part in recent years that these later stages have received the attention tliat is their due. The study of later stages has been the principal method of research by Hyatt, Beecher, Clarke, Schuchert, Smith, the author, and others. From this method of study important results have been attained in our knowledge of the filiation of several groups of invertebrates. From his researches Professor Hyatt discovered the fact, that in the old age of the individual, stages may also be found. These senile stages recall in a broad way the some- what similar stages seen in the young. Successive senile stages, however, when repeating larval or adolescent stages, do so in the hiverse order of succession from that of their 90 ROBERT TRACY JACKSOX ON aiDpeaniuce in the young. Senile stages are prophetic of types which may be found in regressive series of the group to wliich the animal belongs, as shown by Hyatt in cephal- opods and by Beecher in l>racliiopods. Senility is marked by the loss or reduction of those characters wliich are fully evinced in the adult as specific and generic characters, and Ijy the taking on of features of its own period of growth. To (luote Hyatt ('97), " The cycle of the ontogeny is, therefore, the individual expres- sion and abbreviated recapitulation of the cycle that occurs in the phylogeny of the same stock ; and, while the embryonic, nepionic, and neanic stages give us, in abbreviated shape, the record of the epacme, the gerontic stages give, in a similar manner, the history of the paracme." Professor Hyatt formulated the law of senile characters as follows : In the old age, stages are found, which are similar to stages found !n the young, and are pro- phetic of types to he found in degradational series of the group to which the animal belongs. The above principles and their application, Hyatt's and Cope's principle of accelera- tion of development, the well-known principles of parallelism, and the dynamic relations of the organism to its environment of Cope, Hyatt, and Ryder, form the central working principles of Prof. Alpheus Hyatt and his followers, and may be justly termed the Hyatl school. The pi-inciple of localized stages in development as described in this paper is in the direct line and the natural outcome of this method of work. Studying organisms in accordance with the above laws, one expects to find stages, in a more or less marked degree, in the immature organism and also in the old age. In the adult one expects to find the full species characters evinced, and, excepting as the adult represents one step in a chain of organic series, stages are not looked for. From observations on animals and plants, evidence has been obtained which points to the conclusion, that, in addition to stages in the young, and in the old age, stages may be found in localized parts throughout the life of the organism. In organisms that grow by a serial repetition of parts, it is found that there is often an ontogenesis of such parts, which is more or less closely parallel to the ontogenesis of the organism as a whole. In the ontogeny of sucli localized parts in a mature individual, we find stages in development during the growth of the said parts which repeat the' characters seen in a similar part in the young individual. To state it briefly for the moment, such localized stages have been observed in the leaves of plants, in branches or suckers of plants, in the budding of some lower animals, as Hydra and Galaxea, in the plates of crinoids and Echini, in external ornamentations in mollusks, and in the septa of cephalopods. Localized stages in development must be clearly differentiated from stages in develop- ment of the organism as a whole. They are features seen in localized parts throughout Localized stages In development. ^1 the life of the individual, or are cajjable of being brought into existence by certain condi- tions throughout the life of the individual. Localized stages are essentially features of the adult, although they may be evinced earlier or later than what wovdd technically be con- sidered as the ephebic period. In Strassburger's Botany ('98) occurs a statement which is to the point in the present studies. It is as follows : " Whatever is true of the development of a plant from the embryo, is also, as a rule, applicaljle to its further growth from the growing point, and, consequently, a knowledge of the mode of development at the growing point is of great importance in detecting homologies." The same principle is applicable to many animals. As stages found in the young repeat the characters of ancestral forms, so stages found in localized parts repeat the characters of ancestral forms, and their adult equivalents are to be sought in more primitive, sometimes more specialized, living or fossil allies. From localized stages we may gather suggestive clews to the phylogeny of a group. Localized stages have an important bearing on the study of variation. In the arrested or specialized development of a localized part, characters may be seen which are comparable to more or less exceptional individuals, where the whole organism has an arrested or other- wise modified character. The localized and the individual variation may be reversionary or progressive in the line of variation of the group, and comparable to fossil or li\dng, ancestral or specialized membei's of the group. From this point of view, localized stages deserve careful stud}^ Besides atavic and progressive variation, aberrant variation as well as parallelism may be represented in localized or individual variation. To which class of variations a given character belongs, cannot usually be safely assumed without a study of the young and related forms both living and fossil. In studying localized stages of developTnent, it is found tliat there are certain general methods of their expression Avhich should be con.sidered. In the ontogeny of a localized part, the stages may be transitory, and only seen if the part is observed at a certain period of its growth. Such are the earlier stages in the growth of individual leaves, the simple leaves at the base of suckers of many plants, as oaks, ashes, Ailanthus, the simplest con- dition of budding corals and of the plates of crinoid stems and Echini. On the other hand, localized stages in developn>ent may be permanently retained in certain areas of the part. Cases of such local permanent retention of primitive features are the distal tips of leaves which resemble the whole leaf of the young, as seen in the Tulip-tree and in the compound leaves of Ailanthus, ashes, Phoenix, Areca, Pteris ; or the proximal portion of the leaf may repeat the character of the simpler condition, as in Gymnocladus. The septal sutures of Ammonites retain permanently on their inner umbilical border a simpler condition. The portion of the organism which is represented in the localized stage may be more 92 ROBERT TRACY JACKSON ON or less extensive. It may be reduced to a single part, as a leaf or even a portion of a leaf of a plant, or a plate of an echinoderni ; or it may include a series of parts in which local- ized stages are observable, as in suckers of plants, certain portions of a branch (Larch) , and diseased, i-eversionary, or otherwise modified branches of plants (Red Cedar, Tulip- tree) . It is obvious that this latter distinction is only a modification of the first, but yet is convenient to maintain. Localized stages may be developed in the natural growth of the individual, or they may be evinced on\y under more or less abnormal or pathologic conditions. Cases of this are reversionary suckers in the Pitch Pine, suckers developed on the felling of trees, growths on mutilated branches of Liriodendron and Ailanthns, tuft-like branches of the Red Cedar with acicular leaves. Youthful or reversionary features may be developed only at certain definite areas of the organism. Such are compound leaves at the base of AmpeJojJsis tricusjndata, ovate leaves on the cui-rent season's growth of the same, arrangement of leaves on the current season's growth in the Larch. In general, suckers from the base of the trunk or roots of trees have a strong tendency to reproduce nepionic or reversionary characters. If there is truth in the principle of localized stages in development, from them we should be able to predicate with some accuracy the conditions of the j'oung, and concur- rently of ancestral types as well. I think that this may be done. The existence of local- ized stages was first observed in Palaeozoic Echini and was published in Studies of Palaeechinoidea ('96, p. 228). The occurrence of locahzed stages, and their bearing, may be expressed in the follow- ing law, which should be compared with the laws concerning youthful and senile stages : Throughoift the life of the mdividual, stages may he found in localized jiarts, ivhich are similar to stages found in the young, and the equivalents of which are to be sought in the adults of ancestral groups. While this law covers the usual conditions, it is possible and even probable that degradational or progressive features may appear as localized stages. To include such cases the following clause may be added : The equivalents of regressive or progressive localized stages are to he sought in the adults of degradational or progres- sive series of the group. My sincere thanks are due to Mr. Charles E. Faxon of the Arnold arboretum. Harvard university, for reading the manuscript of the botanical portion of this paper, and for help- ful suggestions on the same, also for aiding me with material. For seedhngs and other material, studied at the Arnold arboretum, my thanks are due to Prof. Charles S. Sargent, Director of the Arboretum. For many seedlings valuable in my studies I am indebted to the kind interest of Miss Marian C. Jackson, the Shady Hill nurseries of Bedford, Mass., and others as mentioned in the text. LOCALIZED STAGES IN DEVELOPMENT. 93 Localized Stages ix Developmext in Plants. In many cases in the following pages simple stages in the development of seedlings are described, often in considerable detail, bnt these are not to be confused with localized stages in development which are compared with them. Sir John Lubbock's work on seed- lings has been a great help and is frequently referred to. In the nomenclature of stages in development of animals, the term nepionic is applied to stages innnediately succeeding the embryonic. The term has not been applied before to plants, but as cotyledons are the last of the truly embryonic features, the immediately succeeding growth is considered as the nepionic stage. In the higher plants the tij^ of the leaf is formed first, and usually growth ceases early at that point, it being transformed into permanent tissue (Sachs, '75). Such being the fact, it is evident that the proximal portion of the leaf is formed last. The tip of the leaf should be the most primitive portion, and the proximal portion, usually at least, the most specialized portion, as is shown to be the fact in many cases in the following pages. If a leaf undergoes an arrested development from any cause, the distal tip at least will be formed, and the proximal portion will fail to develop or will be modified in varying degrees. In progressive evolution newly added characters will be likely to make their appearance at the proximal end of tlie leaf. As a corollary, in regressive evolution, regression will tend to be evinced by a dropping out of characters at the proximal end of the leaf. Aquilegia canadensis. In the seedling columbine, AquiUgia canadensis L. (PI. 16, fig. 16), the cotyledons are broadly rounded, with long petioles and a slight emarginate distal notch. The first nepionic leaf is trifoUolate, the median leaflet having two marked notches, and each of the lateral leaflets one slighter notch on the lower side. Later nepionic leaves are similar. In the adult (PI. 16, fig. 17) the leaf has three bi-anches. The two lateral divisions are trifoliolate and repeat the form of the median division. The terminal division is trifoliolate, like the whole nepionic leaf. The median leaflet has two major clefts, comparable to the two indentation.s of the median leaflet of the nepionic leaf, and the two lateral leaflets each have a major cleft on the lower side, comparable to the notches of the lateral leaflets of the nepionic leaf. While the adult leaf has relatively deeper notches and in addition has minor dentations, we may see, in the leading featui-es of the terminal leaflet, a repetition of the characters of the Avhole nepionic leaf of the seedling. LiRiODENDRON TULiPiFERA. In the Tulip-tree {Liriodendron taUpifera L.) the seed- ling (PL 16, figs. 8, 11) has simple lanceolate cotyledons. The first nepionic leaves ai-e alternate, distally emarginately truncate, rounded for the rest of their outline. The angle between the truncation and cui'ved sides in the first nepionic leaves is rounded, but in 94 ROBERT TRACY JACKSON ON later leaves becomes comparatively sharp, as shown in different leaves of the specimens figured. The tliird nepionic leaf of Fig. 11 has slight emarginate lobes, the beginning of the lobes wliich are characteristic of the species. Gradually during later growth the typical form of leaf of the species is built up. In young trees, up to six or ten feet in height, the leaves, as observed in many cultivated specimens, are large and \ngorous and four-lol)ed (PL 16, fig. 1), no six-lobed leaves having l)een observed in such individuals. In the adult tree the tyjjical leaves are four- or six-lobed (PL 16, fig. 12) . Six-lobed leaves are figured in Professor Sargent's Silva as the characteristic leaves, and although they are in some incUviduals uncommon or absent, they ax'e usually abundant in adult trees, as far as my observations have gone. It should also be said that four-lobed leaves are abundant on all typical trees. When four- and si.\-lol)ed leaves occur on the same branch, the six-lobed leaves are on the proximal end, and four-lol)ed leaves on the distal portion, showing this definite relative position in the cases observed. In this species the leaves are very variable, but in all variations the distal truncation is never departed from, this distal portion of the leaf (as noted in many other cases) always retaining the character wliich is e\'inced in the young nepionic leaves. Variations are especially noticeable in late or feeble growths, especialW at the ends of branchlets, but may occur as isolated individual leaves on any part of the branch. In PL 16, fig. 13, is represented a characteristic variation of the tip of a branch from the same tree as Fig. 12. Leaf 1 has two lateral sinuses moderately developed, a little more so than leaf 3 of Fig. 11, but similar to the characteristic form seen in somewhat older seedlings. Leaf 2 has very slight lateral sinuses, and leaf 3 is a close approach to leaf 1 of the seedling (Fig. 11). In PL 16, fig. 4, is represented a small reversionary leaf from the same tree, which is similar to leaf 4 of the seedling (Fig. 11). On the same tree a branch had been mutilated by browsing cattle, and a weak late growth (July) was thrown out. Two of these leaves are represented in PL 16, fig. 7. One leaf has slight marginal sinuses, the other ' is entire, both closely resembling leaves of the young seedling (Fig. 11). All of these aberrant- leaves are seen to be distinctly reversionary in character, closely resembling the condition seen in an earl}' stage of the seedling. Accorchng to the views expressed, these may be considered as leaves which have undergone an incomplete development and are reversionary througli a failure in their individual ontogeny to develop full specific characters. In adult Lirlodendron tullpifera leaves are occasionally^ found which have eight lobes (PL 16, fig. 3), there being two small marginal lobes in addition to the six lobes character- istic of the species. Holm ('90) has also described eight-lobed leaves, and my figure is taken from that author. These leaves have developed more than the full specific char- acters and would tend to show what may be expected as the next step in the evolution of LOCALIZED STAGES IN DEVELOPMENT. 95 the type, provided additional species are differentiated in the progressive line of evolution of the group. Besides reversionary leaves, reversionary individuals ai-e not uncommon in this protean species. Frequently trees are seen in wliich all tlie leaves are four-lobed (PI. 16, fig. 1), similar to a stage attained early in an individual wliich has six-lobed leaves in the adult. At the Arnold arboretum, there is an interesting tree which is highl\' reversionary in character. All or essentially all of the leaves are rounded, distally truncate, with slight angles at the lateral terminations (PI. 16, fig. 10), closely resembling the nepionic leaves of the seedling (PI. 16, fig. 11, leaf 4). A branch of this tree which sliows a progressive locahzed vai'iation is represented in PI. 16, fig. 9. It is progressive for the individual because more specialized than the tj-pical leaves, although if it were on a normal tree of the species it would be a regressive variation. Leaf 1 has one slight lateral lobe on the middle half of each side ; leaf 2 has two slight lateral lobes corresponding to the two well- developed lobes of a normal tree (Fig. 12). Leaf 3 is nearly orbicular, truncate, rever- sionary, and comparable to early leaves of seedlings. A tree with similar leaves in the Botanic garden in Washington M'as desci'ibed by Holm ('90). On Pearl street, Dorchester, Mass., there is a tree in which the typical leaves have six slightly developed lobes as in leaf 2 (PI. IG, fig. 9). In another tree at the Arnold arboretum, the tyjiical leaves are four-lobed as in Fig. 1. This is not an uncommon variation, as noted, and many such leaves occur on all typical trees. It ))ears a close I'esemblance to Liriodendron g'ujanteum, Lesq., of the Cretaceous. In the development of L'lr'iodendron tid'ip'ifcra, there is a distinct progressive series of leaf differentiation. Starting with the young seedling, we find first a leaf which is rounded, distally truncate (PL 16, fig. 5); next the terminal angles become sharpened (Fig. 6); then lateral lobes become gradually differentiated, at first slightly, then strongly marked (Fig 1) ; then two additional lobes appear (Figs. 2 and 12), giving the full sjiecific characters. As a variation in the direct line of progressive differentiation, two more lobes may be differenti- ated (Fig. 3). In regressive leaves at the tips of branches, etc., as described, these same characters are repeated, but in inverse order, a slightly regressive leaf drops out the two basal lobes (Fig. 2a-b), a more regressive leaf drops out two more lobes (Fig. 2 c-d), an extremely regressive leaf becomes rounded at the angles (B^ig. 2 e-f) and repeats the characters of young seedlings. It is seen that progressive development jiroceeds by add- ing characters at the proximal end of the leaf, and regression is marked by the dropping out of characters at the proximal end. The distal end never suffers any considerable change. Turning to the fossils, we find that Linodeiidronprimaemint Newb., of the Cretaceous, is an ancient form Avhich has a rounded leaf, distally truncate, resembling the leaves of the young seedling (Fig. 8). Liriodendron meeki Heer, of the Cretaceous, has slight marginal 96 ROBERT TRACY JACKSON ON sinuses, being quite close in form to leaves in late growth of seedlings, or regressive leaves of adults (Fig. 13, leaf 1). In L'irlodendron gifjanteiini Lesq., from the Cretaceous, the leaf is four-lobed, with av ell-developed sinuses, and resembles leaves of young trees, or four- lobed leaves of adults (Fig. 1). Holm ('90) has questioned the validity of these fossil species, because variations equivalent to them may be found in our modern species. His objection may be met by the reasonable suji^aosition that, in fossilization, only the average leaves of the tree stand any probable chance of preservation. Aberrant leaves, in virtue of their small number, stand relatively a slight chance of preservation as fossil representatives of ancient floras. AiLANTHUS GL.WDULOSA. In AUanthiis glandulosa Desf. the seedling (PI. 16, fig. 15) has broad, rounded cotyledons of leathery consistency. The first two nepionic leaves are opposite, compound, composed of three leaflets each. The terminal leaflet is lanceolate, the lateral leaflets have entire margins. Succeeding leaves are alternate in arrangement. They are also trifoliolate, but soon more leaflets are added. A specimen seven inches high has seven leaflets on the youngest or last added leaves. Part of the leaflets of the two upper leaves of PI. 16, fig. 15, have already acquired slight notches, wliich are a characteristic feature of adult leaves. According to Lubbock ('92) the first nepionic leaves of Ailanthus glandidosa var. rubra are also trifoliolate. The adult Ailanthus glandidosa has very large compound leaves, imparipinnate, with about 25-33 leaflets. The distal ends of the leaves closely resemble the first nepionic leaves of seedlings, differing principally in the added marginal notches. In an adult tx'ee in Cambridge, at a point where a branch had been broken, a weak late growth was thrown out. In this growth all the leaves had few leaflets, and one leaf had only three ; therefore, excepting for its marginal notches, repeating the characters of the first nepionic leaf of the seedling. In all of these depauperate leaves the terminal and other leaflets were similar to those seen at the ends of normal adult leaves. The reduction was in the suppression of the proximal portion of the leaf, or that portion wdiich is formed last in the ontogenesis of the leaf. This species suckers freely from the roots, suckers often appearing at a considerable distance from the base of the trunk. Suckers at first usually have simple leaves (PL 16, fig. 14), though occasionally the first leaves seen were trifoliolate. These simple leaves are alternate, ovate, elongate, similar to, but relatively shorter than, the distal leaflet of the leaves of seedlings. Succeeding the simple leaves are compound leaves, first ti'ifoliolate, later with more leaflets, the leaves all being alternate in arrangement. It is a striking fact, the only case so far seen, that the suckers are simpler, more primitive than the seedling. Whereas the seedling starts with opposite trifoliolate nepionic leaves, the sucker begins with alternate simple leaves. In the Ailanthus then we find nepionic characters repeated in suckers and I'egressive leaves of feeble growths. LOCALIZED STAGES IN DEVELOPMENT. 97 Rhus toxicodendron. The seedling of the Poison Ivy (^Hhus toxicodendron L.) has two evenly rounded, fleshy cotyledons (PI. 16, fig. 18). The first nej)ionic leaves are trifoliolate and opposite. Succeeding leaves are similar but alternate. The terminal leaflet has a short stalk, but lateral leaflets are sessile as in the adult. Lateral leaflets of these early leaves present a small lobe on their proximal borders. The leaves of the adult differ little from those of the seedling except in the lengthening of the stem of the terminal leaflet and the usual absence of lobes on lateral leaflets. While this is true at West Chop, Mass., where the soil is barren, in fertile soils growth is more luxuriant and lobation is commoner. Als(j in vigorous adults there may be several lobes instead of a single lobe in individual leaflets. Simple leaves are occasionally seen in adults. Leaves near the base of the adult vine (nepionic area) have a tendency to produce lobed leaves similar to those of the seedling. \i\ seedlings grown in fertile soil nepionic leaves are occasionally more lobate than in the specimen figured. Lateral leaflets may have two lobes and the terminal leaflet a lobe on either side. Such extra lobation is not common, however, and tlie specimen figured is typical of most of the seedlings seen. Primary (nepionic) leaves in this genus show considerable variation, according to Lub- bock ('92) being scale-like, simple, or, as he says in one species, Rhus typldna, tri- foliolate. In R. toxicodendron, the trifoliolate nepionic leaves, so similar to those of the adult, mark it as a species with an accelerated development, a feature common in degradational species. The degradational or specialized character of this species is indi- cated by its creeping habit, its development, and perhaps by its toxic properties as well. ViTis. In the grape, Vitis (garden varieties), the cotyledons are opposite, ovate, entire. The nepionic leaves are cordate, slightly trilobed. In later growth, leaves become more lobate, and tendrils, which are absent in the young, begin to appear. In adult vines the young leaves, when they first appear, are strikingly like the seedling, not taking on the full lobate character until later growth. Nepionic leaves and young leaves of new growths resemble fossil species of Vitis in their trilobed form and general sim- plicity of outline. Ampelopsis quinquefolia. In the Virginia Creeper (Amjyelopsis quinquefolia Mich.) the seedling (PI. 16, fig. 19) has ovate cotyledons resembling those of A. tricu- spidata. The first two succeeding nepionic leaves are trifoliolate, alternate, as in A. tri- cuspidata, but they differ from that species somewhat in form; compare Fig. 19, and PI. 17, fig. 20, The third leaf has attained adult characters. The adult has compound leaves of five leaflets, not unifoliolate leaves, as in A. tricusjndata. The adult does not present localized stages, excepting that occasional leaves are reversionary in being trifo- liolate. These leaves may be borne on any part of the plant, and occasional branches bear many such leaves. This is especially seen in late terminal branches. / 98 ROBERT TRACY JACKSON ON Ampelopsis TRicrspiDATA. The Japanese Ivy, AmpeJopsis trinispldata Sieb, and Zucc. (J[. veltchii Hort.), which is extensively cultivated as an ornamental vine, presents striking features. In the seedling (PI. 17, fig. 20) the cotyledons are broadly ovate, entire. The nepionie leaves are trifoliolate and alternate. The individual leaflets of these nepionic leaves are irregularly ovate and dentate. It is noticeable that lateral leaflets conform in outline to the shape of the terminal leaflet, and also that dentations are absent in those portions of the leaflets which lie adjacent to one another, as in .1. quincpiefolia. This trifoliolate stage is retained for a considerable period, through the first year's growth in the specimens observed. In seedlings of the second year's growth, trifoliolate leaves occur on the proximal part; but beyond them the leaves (PI. 17, fig. 21) are unifoliolate. subcordate, deeply denticulate. This form of leaf is retained throughout the second year. In adult Ampdop)sli< tricuspldata localized stages in development are very marked. At the base of the vine, and to a distance of three or four feet from the root, all the leaves are trifoliolate (PI. 17, figs. 23, 25), repeating in form the nepionic leaves of the seedling (PL 17, fig. 20). No trilobed or cordate unifoliolate leaves are found at this area in vines raised from seed. In vines raised from cuttings, as is frequently done, the leaves at this area do not have the trifoliolate character, but are unifoliolate and trilobed. I am informed by a nurseryman that he adopts the method of propagating by cuttings to gain uniformity in the leaves of the vine. The occurrence of typical nepionic leaves at this area is in entire accord with what is shown in regard to suckers from the base in many plants; namely, that at the nepionic area there is a tendency to produce nepionic leaves throughout the life of the individual. Beyond the trifoliolate leaves at the base, all the leaves on the old wood (preceding the current season's growth) are unifoliolate and trilobed (PI. 17, figs. 22' 25), this being the " character" leaf of the species. In an adult in the current season's growth, still a third type of leaf is found. This is cordate, deeply toothed (PL 17, figs. 24, 25), and repeats the form wliidi is characteristic of the second nepionic stage of the seedling (PL 17, fig. 21). The leaves of the adult in this species, which at first sight appear to be simple, should be considered compound leaves, reduced to a single leaflet. The truth of this is evinced by the fact, that, when the leaves drop in the autumn, an articulation develops, and the leaves separate from the petiole at the proximal border of the blade. The petiole may remain in place for a considerable time after the fall of the single leaflet. The trifoliolate leaves at the base of the vine separate from the petiole in a similar iruinner, but leave three scars at the distal end of the petiole instead of a single one. Ampelopsis triciispndata may fairly be considered a regressive species, in which the unifoliolate character is developed by dropping out the two lateral leaflets from the proxi- mal portion of the leaf. In the adult, when the leaves come out in spring, those at the LOCALIZED STAGES IN DEVELOPMENT. 99 base of the vine are all trifoliolate (PI. 17, fig. 25, area a) ; those on the old wood are unifoliolate, trilobed (the same figure, area b) ; and those on the new growth are cordate dentate (same figure, area c). There are thus to be seen three zones or localized stages : a, which repeats nepionic characters ; b, which has attained full specific characters ; and c, whicli repeats the second nepionic stage of the 3'oung. Plants var3^ so much in the form of their leaves that Ampelopsis tricuspidata is noteworthy on account of the constancy of the form of its leaves. At the base of plants raised from seed the leaves are always trifoliolate ; when unifoliolate trilobed leaves appear, they mark a sharp line of distinc- tion, and very rarely do more trifoliolate leaves occur; cordate leaves are found only on branches of the current season's growtli. In the diagram (PI. 17, fig. 25), the current season's growth is represented as area c, or on the periphery. Of course in practice new branches may start out from any part of the plant, but where\'er they originate, they are marked by the same type of leaves. When new branches originate from the base within the trifoliolate leaf area a, then cordate leaves immediately succeed trifoliolate leaves, as in seedlings. Acer rubrum. The seedling Red Maple, Acer nibrum L. (PI. 17, fig. 28), has two long, strap-shaped cotyledons, rounded distfilly. The first nepionic leaves are opposite, elongate, cordate, acuminate, dentate. They already show indications of the trilobed character of the species in the slightly larger lateral lobes near the base of the leaf. The second pair of leaves is elongate, but differs from the first in the greater develojnnent of the two lateral lobes, rendering the leaf trilobate ; but the median lobe is markedly elongate. The same features, though in slightly varying degrees, are characteristic of seedlings of Acer saccharum Marsh, A. spicattim L., A. platanoides L., and A. pseudo- platanua L. In Acer pennsylvanicum L., the first pair of nepionic leaves is simpler than in the species noted, being ovate, dentate, with no evidence of a trilobed character as described by Mr. Deane ('96). This species in its development is structurally the most primitive species of maple seen. As the Red Maple grows older, the trilobate character becomes more marked, and two additional lateral lobes may appear on the proximal border of the leaves. The fea- ture of change is the relative shortening of the median and enlargement of the lateral lobes. The leaf of the adult tree is trilobed or slightly five-lobed (PI. 17, fig. 29, leaf 1). Individual trees with trilobed leaves may properly be considered more pilmitive in char- acter than those with five-lobed leaves, as they bear a closer resemblance to the young and fossil forms; also they are less differentiated on the proximal portion. In the Red Maple, young suckers from the base (PL 17, fig. 27), or other part of the tree, have trilobed leaves in which the median lobe is elongate, as in the seedling. In vigorous shoots, or young leaves at the tips of branches (PI. 17, figs. 26, 29), or in the \ 100 ROBERT TRACY JACKSON OX axils of older leaves, the leaves are also trilobed, with an elongate, median lobe, as in the seedling. In Acer sjjicatiim Mr. Deane ('96) observes that, " The leaves on the ends of new shoots in the old plants resemble in shape and size the first leaves of the seedling." This and many other facts are shown in Mr. Deane's very interesting collection of seedlings. Elongate weakly trilobed leaves on terminal shoots, similar to the seedling, also occur in the White Maple (Acer saccharinum L.), Moose-wood (^Acer pennsylvanicu77i), and Norway Maple (Acer platanoicles) . In the Moose-wood the leaves may even be entire, as noted in the young seedling of that species. Acer platanoides. In Acer platmioides the leaves are palraately five-lobed, but seedlings closely resemble the seedlings of the Red Maple. Suckers froin a stump of this species (PI. 18, fig. 34) at tlie Ijase, had trilobed leaves wuth an elongate median lobe, as in the young. The succeeding leaves, however, were palmately five-lobed, nearly or quite as in the adult. Similar trilobed leaves occur in suckers at the base of the White Maple (^Acer saccharinum). Chinese and Japanese Maples. In China and Japan there is a very interesting series of primitive types of maples, for the opportunity of studying which I am indebted to the Arnold arboretum. Acer oblongum Wall., from the Province of Hu-Peh, China, Coll. Dr. Aug. Henry. In this species the leaves (PI. 17, fig. 30) are elongate, oval, acuminate, margins entire. It would hardly, if at all, be recognized as belonging to this genus, were it not for the fruit. Besides the median vein, two strong lateral veins diverge from the base, as is usual in maples. All the evidence of palaeontology and ontogeny shows that entire leaves are more primitive than dentate or lobed leaves. Therefore we may properly consider this as an extremely primitive type, in fact structurally more primitive than any other known living or fossil species of maple. It is also more primitive structurally than the known seedling maples. Acer carpinifoJlum S. and Z., from Nikko, Japan, Coll. Prof. C. S. Sargent, is another very striking type. The leaves (PI. 17, fig. 31) are elongate, oval, acuminate, with serrate margins. The leaves at the end of the branch have slight marginal undulations about 15 mm. from the base, as in the figure. Leaves situated nearer the base of the branch do not show these undulations, but are slightly inequilateral. The veins are given off obliquely from the midrib and are parallel to one another, no strongly marked lateral veins existing, as in Acer oblongum. This species may be considered as structurally more specialized than Acer oblongum on account of its dentate margins. Acer crataegifoUum S. and Z., from Nikko, Japan, Coll. Prof. C. S. Sargent, is an interesting type. The leaves (PL 17, fig. 32) are broadly oval and slightly dentate, two LOCALIZED STAGES IN DEVELOPMENT. 101 of the serrations on the sides being strongly marked, so that the leaf strikingly resem- bles the first nepionic leaves of the seedling of the Red Maple (Fig. 28, leaf 1). It is also quite like the simplest of the fossil maples, as Acer indtvistim Web., of the late Ci'etaceous (Laramie) and Tertiary'. All the leaves of this species are similar, no vari- ation having been observed. It is a distinctly archaic type in its form. Acer tartaricum L. var. gbuiale Maxim., from Jesso, Japan, Coll. Dr. H. Mayr, presents interesting features. On the proximal end of the branchlets (PI. 17, fig. 33) are two bluntly oval, very slightly serrate leaves; similar leaves occur on many speci- mens seen in the herbarium of the Arnold arboretum. Beyond this single pair of leaves all the leaves are of a strikingly different form (Fig. 33); they are elongate, slightly trilobed, with serrate margins. Individual leaves show considerable variation in the trilobed character, some being less, others a little more, deeply trilobed than the leaves figured, which represent a fair average. This type of leaf bears considerable resem- blance to the weakly trilobed leaves seen in the second pair of leaves and in the later leaves of young Red Maples (Fig. 28) and other species. It may, therefore, in the character of these leaves be considered a primitive type but more advanced structurally than Acer crataegifol'mm. In regard to the two oval nearly entire leaves seen at the base (PL 17, fig. 33), they may be considered a localized reversion to a simpler type, and as such may be compared to Gledltschia trlacanthos in which the proximal leaves are once compound, the distal being more specialized and twice compound. (See p. 102.) Fossil Maples. In Acer indlvisum Web., of the late Cretaceous and Tertiary, we find a type in which the leaves are either without lobes, or with two slight lobes quite similar to the first nepionic leaves of Acer ruhrum and A. j>seudo-iilatanus. In the Creta- ceous and Tertiary maples the species are almost universally trilobed, and an elongate character of the median lobe is of frequent occurrence, as in Acer trilohatum A. Br. and A. dec%2ylens Heer. The trilobed character of maples finds, then, an expression in many fossil species and primitive living species, as Acer crataegifolium and A. ruhrum. An elongate trilobed form is seen in some fossil species, in the young of all species observed, and in vigorous growths, and leaves of terminal branches of Acer ruhrum and many other species. Acer pennsylvanicum forms a partial exception to this rule, because the first pair of nepionic leaves shows no trilobate character, tliis feature being developed in later growth. Species such as the Sugar, White, and Norway Maples, besides other features are differentiated by having two lobes added to the proximal end of the leaf, but in the young and degradational leaves they show the more primitive trilobed char- acter. Negundo aceroides. In the Ash-leaved Maple, Negundo aceroldes M., the seedling has simple trilobed leaves. My material is imperfect, and first nepionic leaves and coty- 102 ROBERT TRACY JACKSOX OX ledons are not shown on the specimens. In later growth the leaves are trifoliolate. In the adult the leaves are very variable in outline and degree of division, having from three to seven leaflets. Occasional simple leaves are also seen as reversions. The terminal and lateral leaflets vary much in outline (PL 18, fig. 3G), being ovate, denticulate, trilobed, or even twice pinnate. When trilobed, as in the terminal leaflet of the figure, they bear considerable resemblance to the nepionic leaves of the seedling. A sucker from the base of an adult (PL 18, fig. 35) has first a simple trilobed leaf, like the young, also like the simpler fossil and living species of maples. The second leaf of this sucker is trifoliolate. In two other suckers, two simple trilobed leaves precede the first compound leaves. The seedlings, suckers, and often' the terminal leaflets, therefore, show distinctly reversionary characters. Gymnocladus disicus. In the Kentucky Coffee-tree {Gi/mnocladus disicus L.) the leaves (PL 18, fig. 37) are very large and twice paripinnate. The proximal end of the leaf, however, has two, three, or four simple leaflets, commonly four. The total num- ber of leaflets on large leaves counted varied from seventy-five to one hundred and seventeen. I have not seen seedlings of this species, but it suckers freely from under- ground roots. The sucker (PL 18, fig. 38) has once compound leaves, composed of few leaflets, four in the specimen figured, which was the smallest number seen. Later leaves on the sucker rapidly increase in the number of leaflets and soon become twice compound. From evidence in other types, it is probable that the nepionic leaves of the seedling are very similar to the first leaves of the sucker. In many cases, as noted, the distal portion of the leaf repeats the form of nepionic leaves. It is interesting to note that here the proximal portion of the adult leaf resembles the once pinnate condition of the leaf of the sucker and presumably of the seedling ; in so far it is reversionary in character. Gleditschia triacanthos. In the Honey Locust {Gleditschia triacanthos L.) the seedling has thick, fleshy, rounded cotyledons (PL 18, fig. 39). They are auricled at the base, nearly embracing the stem, as shown in Fig. 39a. The nepionic leaves are alter- nate, once compound, paripinnate. The first leaf has numerous leaflets, sessile, not quite opposite one another. Succeeding leaves are similar, but progressively larger, with more leaflets. The leaves of the adult are once or twice paripinnate. The twice pinnate leaves are borne on the new growth at the ends of tlie branches; but the leaves of the old wood or proximal portion of the branches are once pinnate. The old wood, therefore, bears the more primitive, the new wood the more specialized type of leaf. Occasion- ally a few once compound leaves are seen on the new wood as a reversionary variation. The distal end of once pinnate leaves or the end of the second division of twice compound leaves repeats the form of the nepionic leaves of the seedling. It is noted in many cases that the distal end of adult simple or compound imparipinnate leaves closely resembles LOCALIZED STAGES IN DEVELOPMENT. 103 the form of the first nepionic leaves of the seedling. Such seems to be the case usually in paripinnate leaves as well. Besides the cases noted numerous confirmatory cases may be seen by looking over Lubbock's Ijook ('".'2) on seedlings. In plants where later leaves are radically different from the seedling, as in many acacias, cactuses, etc., of course this parallelism would not hold true. At least occasional exceptions occur, however, as in Seshania tomentosa Hook, and Arn., figured by Lubbock ('92). Li this type the first nepionic leaf is simple, but later leaves are paripinnate. In twice compound leaves of the Honey Locust frequently a single leaflet takes the place of a compound leaflet, evincing a reversionary character. EucHARiDiUM GRANDiFLORUM. The Seedling of Eucharidium grandifloruni Fisch. and Mey., as described by Lubbock ('92), presents a graphic case of the change in the form ErCIIARlDIUM ORAXDIl I.OKCjr. 1. Seedling, X 3. 2. The same, ten days after germination, X 3. 3. The same, showing final form of cotyledons and succeeding nepionic leaves, XI- c. = cotyledon. -^Q^ ROBERT TRACY JACKSON Of leaves during growth. This is reproduced here by the courtesy of Messrs D Apple- ton and Company. Lubbock shows that in the seedling the cotyledons are first sessile, oblono-orbicular, auricled at the base, and with an emarginate tip (Fig. 1). in latei growtl a slight constriction appears near the base on either side. " This basal poHion increases much more rapidly, while the growth of the terminal portion (which is, m fact, the oric/inal cotyledon) becomes gradually arrested." (Fig. 2.) "In its ^^'f J^J^ (fie. r.31) the new portion is both broader and longer than the true cotyledon, and d^ers from it not only in the crenations, but in the possession of a more conspicuous midrib and rather stiff hairs. Not only is this basal portion interesting in its mode of develop- ment, but also fron. its similarity to the subsequent leaves. In fact, * * * it may be said that we have a compound structure formed of a leaf at the base, terminated by the coty- ledon " He describes similar changes in cotyledons of species of Clarkia and Oenothera. These cases are very interesting as cases of accelerated development, m which features ordinarily originating later are shoved back into embryonic stages. They are especially interesting to us here, however, as illustrating localized stages in development m the ontoo-enesis of a leaf, showing that in progressive periods of its growth it may actually acquire features which make the characters of the leaf an epitome of the development of the type. Special attention is called to the fact, that the new additions are made to the proximal portion of the leaf, the distal portion retaining its original characters Patsia japonica. The seedling of Fatsia japonica Decne and Planch. {Araha sieboldii Hort.) (PI. 18, fig. 41) has obovate rounded cotyledons. Succeeding nepionic leaves are alternate, the first leaf is broadly ovate, the second cordate, both finely dentate, and the third leaf is trilobed. The first two leaves closely resemble the leaves of the same stage in Aralia edulis Sieb. and Zucc, as figured by Lubbock ('92). The adult leaves of that species are large and bipinnate. In adult Fatsia japonica the leaves are large, palmately deeply cleft, serrate (PL 18, fig. 40). In two plants some six feet high (raised from seed), which were cut down nearly to the ground, suckers were thrown out. In the sucker (PI. 18, fig. 42), the first two leaves are in one case broadly cordate, dentate, in the other trilobed, both resembling closely the nepionic leaves of the seedling. It should be noted, however, that in the sucker the first leaf is trilobed, the second cor- date whereas the reverse order is the condition of the seedling. Aralia notata Lx. of the Cretaceous is trilobed and closely resembles the trilobed leaf of the seedling and sucker of Fatsia japonica. Hedera helix. In the English Ivy (Hedem helix L.), the seedling (PI. 18, fig. 43) has two broadly ovate cotyledons. Succeeding nepionic leaves are alternate. The first nepionic leaf is broadly ovate, with only a slight indication of a lobe on one side. The second leaf is also broadly ovate, and has a slightly developed lobe on either side. The LOCALIZED STAGES IX DEVELOPMENT. 105 third leaf is a " character" leaf, having nearly or quite the full characters of the species. It is five-lobed, whereas in some other seedlings the third leaf is trilobed; but this is perhaps no more than might be expected in this protean species. The fourth leaf is also five-lobed, but the lobation is not so pronounced as in the third. The fifth leaf, which is very young, is slightly trilobed, resembling the second nepionic leaf. It is reasonable to suppose that in further growth this young leaf would have taken on additional lobes like the third and fourth nepionic leaves. For this and many other seedlings I am indebted to Mrs. Robert T. Jackson. The English Ivy varies greatl}-, but selecting a branch, the fully grown leaf of which is like the seedling figured, a comparison may be made. In such a branch (PI. 18, fig. 44), the fully developed leaf is five-lobed. Passing upward to the youngest leaves at the tip of the branch, we find that the lobes become progressively reduced. The fifth leaf has five lobes, but not strongly developed ; the sixth and seventh are simply trilobed. The eighth leaf is weakly trilobed, .and bears considerable I'esemblance to the second nepionic leaf of the seedling. While the leaves are very variable, it may be said that the young leaves of new growths have fewer lobes or at least more weakly developed lobes than the older leaves on the branches, thus making a more or less complete reversion to the simple condition of the young. It is noteworthy that the simple trilobed leaves of young seedlings and young leaves at the end of growing shoots (PI. 18, figs. 43, 44) bear a close resemblance to Hedera cretacea Lesq., of the Cretaceous. Dahlia variabilis. The seedling of the common Dahlia {D. variabilis Desf.), has simple, ovate leaves, succeeded by pinnatisect leaves. The typical leaves of the adult have three, or more often five segments. Suckers from the crown frequently have simple, ovate leaves at first, as in the seedling. On flowering shoots, especially late in autumn, simple leaves are so common as almost to predominate. In these simple leaves are seen distinct localized reversions to the simple condition characteristic of the young. Tecoma kadican.s. In the Trumpet Vine (Tecoma radicans Juss.) the seedling has rounded cotyledons, distally deeply notched. The first nepionic leaves are simple, den- tate, with petioles. There are two pairs of simple leaves, succeeded by compound, tri- foliolate leaves. In later stages, additional leaflets appear, until the full character leaves are attained. The distal leaflet of adult leaves resembles the simple nepionic leaf. In suckers from the root, cases occur in which the first leaves are simple, as in the seedling. Often, however, the first leaves developed in suckers are trifoliolate, the reversion being more or less complete in different individuals. Fraxikus AMERICANA. The ashes present interesting features in development and localized stages in development. In the development of the White Ash (Fra.rlnus ameri- cana L.) the seedling (PI. 18, fig. 45) has oblong, obtuse cotyledons. The nepionic 106 ROBERT TRACY JACKSON ON leaves are opposite, simple, oval, with acuminate tips and long petioles. Several alter- nating pairs (five or six) of simple opposite leaves appear, all having the same outline, excepting that occasional abnormal leaves are blunter distalh' or even rounded and dis- tally emarginate. These variations in the cases noted usually occur in both leaves of the pair. The first compound leaves, as shown in an older seedling (PL 18, fig. 46), are tri- foliolate, the distal leaflet resembling the earlier simple leaves; the lateral leaflets are similar but sessile. Gradually later added leaves become more differentiated by the addi- tion of lateral leaflets proximally, until there are from seven to nine leaflets, which are characteristic of the species. During later growth, petiolules develop on the lateral leaf- lets, until they are comparatively long, as in tlie adult (PI. 18, fig, 48). In the adult White Ash the leaves (PI. 18, fig. 48) are large, and the terminal leaflet closely resembles the simple nepionic leaves of the seedling. The White Ash suckers quite freely from roots near the base of the tree or from the stump when a tree has been cut down. Such suckers repeat very closely the form of seedlings. One of a number of suckers from the base of a tree some forty feet high is represented in PI. 18, fig. 47. The first leaves are simple and alternate, as is frequent in suckers of the ash, although they are often opposite, as in seedlings. The first simple leaves also are often rounded distally instead of acuminate as in seedlings. These and other variations are more fre- quent in suckers from large trees than from small ones. After more or less simple leaves, usually several, the compovmd leaves appear. The first compound leaves are usually tri- foliolate as in seedlings, in later leaves lateral leaflets are progressively added proximally, as in the growing seedling, also lateral leaflets are sessile as in seedlings. The last of the simple leaves and the compound leaves (PI. 18, fig. 47) are quite strongly serrate, a feature which is less marked or absent in seedlings. In suckers from stumps of large trees that have been cut down, the first leaves are often compound, being trifoliolate or even five-foliate ; nevertheless suckers with simple leaves at their base may be considered the typical form. The only important differences noted between typical suckers and seedlings are that leaves are very commonly alternate in suckers and that they undergo frequently an accelerated development, acquiring adult characters earlier than seedlings. To this may be added considerable variability in the outline of leaves in suckers. In growths thrown out late in the season from any part of the tree, it is noticeable that the lateral leaflets are frequently sessile, in this resembling the character of nepionic leaves. In the adult White Ash occasionally leaves of three or five leaflets, or rarely simple leaves, are found instead of the typical number. Such primitive leaves may fairly be considered as cases of arrested development, in which during the ontogenesis of the leaf the later added characters were skipped. It is to be noted, as observed in many other caseSj that it is the proximal, or last added, portion which is repressed. LOCALIZED STAGES IN DEVELOPMENT. 107 Fraxinus anomala. According to Professor Sargent ('91-'97) Fraxinus anomala Wats, is a small tree or shrub which usually bears simple leaves, but occasionally leaves which are trifoliolate or five-foliate. Such compound leaves are doubtless reversions, and appear to be compai'able to the reversionary leaves just mentioned in the White Ash. One is a case of failure to develop the full specific characters in a progressive type, as the other is a case of developing more than the full specific characters in a regressive type; but both are localized ontogenies of a reversionary character. In Mr. Faxon's drawing Fraxinus anomala, in Professor Sargent's Silva, the typical single leaves are rounded, with long petioles, resembling the rounded leaves seen often in seedlings or suckers of the White Ash. The terminal leaflets of compound leaves, and simple leaves on flowering branches, are acuminate as in other ashes. The development of Fraxinus anomala should be interesting. Fraxinus pubescens. The seedling of the Red Ash (^Fraxinus i^uhescens Lam.) closely resembles that of the White Ash. The cotyledons are similar, and there are five or six pairs of simple leaves which are oval, elongate. They differ, however, from the sim- ilar leaves of the V/hite Ash in being less acuminate distally, deeper green, and the later simple leaves are finely serrate. While serrations occur on all my specimens, they were from one locality, and other seedlings might not be serrate, as adults vary in this character. The compound leaves appear, as in the White Ash, first as trifoliolate leaves, later with more divided leaves. Leaves formed late in the season's growth, in the Red Ash, show a tendency toward sessile lateral leaflets, as in the White Ash. Other Ashes. According to Sir John Lubbock, the seedling of Fraxinus excelsior L. has but one pair of simple nepionic leaves, the second pair being trifoliolate. Both sets are serrate. This species is markedly accelerated in its development, as compared with the Red and White Ash, on account of acquiring compound leaves so much earlier. We find that the seedlings of the Red Ash and the White Ash have simple leaves, followed by compound leaves, the lateral leaflets of which are sessile. These features are repeated in suckers of the White Ash. The distal leaflet of adult leaves of both species resembles the simple nepionic leaves, and leaves of late growths tend to reduce the petio- lules in lateral leaflets, as in the young. \n the Black Ash (Fraxinus sambucifolia Lam.) the primitive character of sessile lateral leaflets is characteristic of the adult, but the dis- tal leaflet has a long petiolule as in other species. The same characters exist in the European Ash (Fraxinus excelsior Jj.) , Fraxinus australis Gay, and usually in F. oregona Nutt. In fossil ashes the lateral leaflets are sessile, as in the young of specialized and adult of what in this feature, at least, are primitive species. Sassafras sassafras. In Sassafras sassafras Karsten {S. officinale Nees) the seed- ling (PI. 19, fig. 49) retains the fruit in place and leafy cotyledons are not developed. The 108 HOBERT TRACY JACKSON ON nepionic leaves are arranged alternately on the stem. The first nepionic leaves are small, ovalh- rouiiikMl ; later leaves retain the same oval outline but increase greatly in size. In the specimen figured the sixth leaf from the base shows slight marginal undulations, which may be the first appearance of lobes ; but such do not often occur until considerably later. In PL 19, fig. 50, is shown the upper part of an older seedhng. The lower part of this specimen had only oval leaves, as in Fig. 49, but the upper part bears three leaves with two or three lobes. In seedlings the lobed leaves occur in the upper part or later growth only ; but in this same area some ovate leaves are not infrequently associated with the lobed leaves. In the adult tree the leaves are borne on short branchlets of the current season's growth. At the base or proximal portion of such branches (PL I'.i, fig. -jl), all the leaves are ovally rounded, ovate or obovate, as in the young seedling. At the upper part of the branch, however, lobed leaves are often developed, although many branches bear no lolled leaves. Amongst the lobed leaves of the upper part of the branch, ovate leaves may or may not develop, this feature being variable. Each branch of the adult, therefore, which bears lobed leaves, repeats the features characteristic of the seedhng, having oval leaves proximally and leaves with two or three lobes distally, with or without associated oval leaves. Lobed leaves are much more common in plants up to five or six feet high than in adidts. As branches of adults bear oval leaves throughout the branch or on the proximal part, when distal leaves are lobed, therefore oval leaves are the domi- nant type, the lobed leaves the exceptional. Professor Ward ('88) maintains the same view. The Sassafras suckers freely from the root, and such suckers repeat the form of the seedling so closely that often they cannot be distinguished until the root is examined. The Sassafras is abundantly represented in the Dakota group (Cretaceous) of this country. These old species (Lesquereux, '91) are two- or three-lobed, similarly to the lobed condition of modern Sassafras sassafras in the later growths of seedUngs or occasional leaves at the tips of branches of adults. The fact that seedUngs start with entire leaves and later acquire lobed leaves like the earliest fossil representatives seems difficult to harmonize with the usual condition, Avhere the first leaves are like the primitive or ancient types, and later leaves are different, being more specialized, as in Liriodendron, White Ash, and Platanus. They may be less specialized, however, as in Ampelopsls trkuspidata and Fraxinm anomala. Granting that in adult Sassafras sassafras the oval leaves are by far the most numerous, also that lobed leaves when existent are pretty definitely limited to a certain portion of the branch, the end, we may fairly assume that the lobed leaves are not the typical leaf of the species, but are localized reversions of frequent occurrence. By the principle of acceleration of development stages are shoved back earlier and earlier, so that we expect to find ancestral stages in the very young. In this species, however, the species features (oval leaves) are found in the young seedling (PL 19, fig. 49), and LOCALIZED STAGES IN DEVELOPMENT. 109 ancestral features (lobed leaves) do not come until late in the growth of the seedling (PI. 19, fig. 50). As shown by Cope, t^pes may lose ancestral chai'acters b}^ retardation of development. That is, features may appear at later and later stages in development until they finally disappear. A common case is the late appearance or entire want of the last molar or wisdom teeth in man. To apply this principle to the Sassafras : if we assume that it is a reversionary type, repeating more or less fully the characters of types earUer than the known Cretaceous lobed forms, then by the principle of retardation the lobed features (Cretaceous) would appear later and later in the ontogeny (seedling) and be present in latest growths of the adult (tips of branches), or absent, as is the case. While this view is open to doubt, it is in accordance with the facts and seems worth consid- eration. Associated genera, as Laurus, Persea, and Cinnamomum, are characterized by leaves which are simple in outline Ijoth in fossil and living species. Platanus occidentalis. In Platanus orieiitalis L., according to Lubbock ('92), the seedling (PI. 19, fig. 51) has cotyledons which are narrow, spathulate, tapering to the base. The nepionic leaves are alternate, spathulate, cuneate, distally bluntly tridentate. I have not seen seedlings of our species, Platanus occidentalis L. ; but we may assume that it is similar to the same stage of the nearly allied European form. Suckers from the base of an adult tree (PI. 19, figs. 55, 56) have leaves which are quite similar to nepionic leaves of the seedling. The first leaves (Fig. ^)o) are elongate spathulate, distally den- tate, laterally nearly or quite entire. While the tips are variable in outline they are fre- quently tridentate as in leaf 1, Fig. 56, and some such leaves occur on all suckers. Leaves at the base of the sucker (leaf 1) are more elongate and spathulate than later leaves, thus making a closer approach to the character of the seedling. A noticeable feature is the fact that the blade of the leaf extends down on tlie petiole, forming an acute angle basally, as in seedlings and many fossil species. The trilobed leaves of the siTcker, as leaves 2 and 3, Fig. 56, closely resemble fossil species of Platanus, as P. primaeva Lesq. from the Creta- ceous (Dakota group) . At the height of several feet from the ground suckers usually develop very large strongly five-lobed leaves numerously and deeply dentate (PI. 19, fig. 58) . The most striking feature, however, is the development of the base of the blade into a lobed basal appendage which is more or less extensively developed. Nei'ves run upon this appendage from the point of disappearance of the main veins of the leaf proper, as shown in the figure. On the lower side of the leaf it is seen (Fig. 58a) that this appendage stands out free from the petiole so that the leaf is perfoliate. At the base of the petiole in the case of these vigorous leaves the branch is enveloped by an extravagant development of the stipules (Fig. 58b), which fuse and form an encircling ruf- fle. These characters are seen frequently also on vigorous leaves of adults especially those growing in wet bottom lands ; but they are quite distinct from the characters of the typi- 110 ROBERT TRACY JACKSON ON cal leaves of the species. After making the above drawings and observations I was much interested to find that Prof. Lester F. Ward ('88) had made similar observations, and he compares this lobate condition of modern Platanus with a sunilar basal lobate appendage in Platanus hasilobata Ward, of the Laramie group (Cretaceous) . There is a difference, however, as P. basilobata has much larger basal lobes and the upper part of the leaf is trilobate instead of five-lobed. In the Cretaceous Aspkliojjhyllain dentafum Lesq. a similar strongly marked basal appendage occurs. Ward ('88) and Lesquereux ('91) note this striking similarity to leaves seen in living Platanus as described, and further the fact that the nervation of A. dentatum is very similar to that of Platanus. All the evidence would seem to show that the Cretaceous Aspidiophyllum is an ancient though somewhat aberrant form of Platanus. It is quite possible that the extravagant development of basal appendages in these several types represents parallel differentiation in related forms rather than direct phjdogenetic association. The tj^pical leaves of adult Platanus occidentalis (PL 19, fig. 57) ai'e broadly pentag- onal, five-lobed, dentate, the base of the leaf extending down shghtly on the stem form- ing an obtuse angle proximally instead of an acute angle as in seedlings, young suckers, and many fossil forms. This basal portion is adnate to the petiole and the midrib extends to its base. As variations, leaves are frequently found which have none of the secondary dentations, as in the specimen figured ; also the two proximal lobes are frequently wanting, and the leaf becomes trilobate and resembles more or less closely leaf 3 of Fig. 56 and fossil alUes as Platanus primaeva Lesq., of the Cretaceous. HicoRiA OVATA. In the Shag-bark, Hkoria ovata (Mill.) Britton, in normal germina- tion the nut rests on the surface of the ground (PL 20, fig. 59) . The first leaves are simple, oval, slightly serrate, with the apex pointed bluntly. The specimen figured has lost the leaves at the lower portion of the stem, but I did not succeed in finding a speci- men with these in place. The fourth leaf is distorted and besides the distal leaflet has a small lateral leaflet on one side. The fifth and sixth leaves are trifoliolate. The distal leaflets of these compound leaves are practically like the first simple leaf, but lateral leaflets are shorter and smaller. In the adult of this species the leaves are compound, composed of five leaflets (PL 20, fig. 61, leaf ]), and the distal leaflet bears a considerable resemblance to the first simple nepionic leaves of the seedUng. At the tips of branches of adults there is characteristically one (sometimes two or three) , trifoliolate leaves (PL 20, fig. 61, leaf 2) . Such trifoliolate leaves are not borne normally on any other part of the branch and represent a localized reversion, comparable to the later stages in development of the leaves of the seedling (Fig. 59). The Shag-bark does not sucker freely ; but a sucker from the root of an adult (PL 20, LOCALIZED STAGES IN DEVELOPMENT. HI fig. 60) shows interesting features. The first three leaves are wanting, the fourth and fifth are simple, resembling the simple leaves of the seedling, except in size and the fact that the fifth leaf is very broad basally. The sixth and seventh leaves are abnormal (a common feature in suckers) , being very large, ii'regular in outline, and each having one lateral leaflet. The ninth and tenth leaves are trifoliolate and near enough to l)e com- parable to trifoliolate leaves of the seedling. In the Shag-bark, therefore, we find a repetition of nepionic characters in suckers and partially in the trifoliolate terminal leaves of branches. Trifoliolate leaves at the tips of the branches of adults as in the Shag-bark have also been observed as characteristic of the Pig-nut, Hicoria glabra (Mill.) Bi'itton, and the Mockernut, Hicoria alba (L.) Britton. QuERCUs ALBA. In the White Oak (Quereus alba L.),tlie seedling (PI. 20, fig. 62) has a long, stout, flexuous root. The cotyledons remain in the acorn, buried just beneath the surface of the soil. The stem is bare for a considerable distance, the first leaves not developing, but axillary buds are prominent, as represented in the figure. The first leaf is ovally rounded, slightly sinuous ; in seedlings this leaf is sometimes more or less sinuous than in the first leaf of the specimen figured. The second and third leaves of the specimen figured are gently lobed, and succeeding leaves in older specimens rapidly take on a more deeply lobed character, until they make some approach to the form of the leaves of the adult (PI. 20, fig. 64) . These early leaves are smooth, and deep green, as in the adult. In suckers from the base of the White Oak the first formed leaves are more or less ovate and slightly sinuous in outline (PL 20, fig. 63). They are variable, but the sucker figured represents a fair average specimen. Later formed leaves rapidly take on mature characters, as indicated by the lobation of the third leaf in the sucker figured. In the adult, on weak shoots, leaves are frequently seen which are simple in outline as in the sucker and seedhng, indicating localized reversionary characters. QuEROUS MINOR. Of the Post Oak [Quereus minor (Marsh) Sarg.) I have not seen seedUngs, but suckei's from the base of adults have ovate or obovate leaves Avith gently wavy margins as in the specimen figured (PL 20, fig 65) . These early leaves have the deep green, roughness, and leathery texture of adult leaves. During further growth the later added leaves rapidly assume the lobed form of leaves of the species, which is very marked in character (PL 20, fig. 66). QuERcus TiNCTORiA. The Black Oak (Qtiercus tinctor'ia Bar.) and Scarlet Oak (Qiceroi.s coccinea Wang.) both occurred in the woods where the seedlings described were collected. As these species ai'e so close, the seedlings with present knowledge cannot under the circumstances be certainly referred to either species. The seedlings (PL 20, figs. 67 and 68) have stout, flexuous roots, but not quite so markedly as in the White 112 ROBERT TRACY JACKSON OX Oak (Fig. 62). The cotyledons remain in the acorn beneath the surface as in the White Oak and some other, perhaps all, species of the genus. The petioles of the cotyledons extend beyond the acorn, embracing the stem, as shown in the seedlings figured. In Fig. 67 the thick, rounded cotyledons are shown with the acorn husk removed. The first few leaves are reduced to scales, axillary buds being the most prominent feature. The first leaves developed (PL 20, figs. 67, 68) vary in size, are ovally rounded, and bear a minute tooth at the end of the median rib, but are otherwise entire. While the speci- mens figured represent typical individuals, sometimes the first leaves have minute teeth at the end of a few lateral veins as well as the median vein ; in such specimens the leaf may or may not have a slightly flexuous margin. In Fig. 67, the first three leaves have only a slight tooth at the distal end, the fourth leaf has a slightly sinuous mai'gin, and minute teeth at the tips of principal veins. In Fig. 68, the first two leaves are entire and smaller than the average. The next two leaves have sinuous margins and teeth at the ends of principal veins. In later growth the leaves become more deeply lobed with pronounced bristles. The leaves of these young oaks are rather bright green, lusterless, covered with fine hairs arranged in a stellate manner. If the growth of the first year dies, a new growth springs up from the base, which is indistinguishable from an actual seedling, and this may happen several times. I have frequently dug up such relatively old plants for seedlings and not found the mistake until tlie scars of previous growths were seen. That is, at this localized area nepionic leaves are pi'oduced continually, as in many other plants, although the plant may actually be several years old. Suckers from the base of an adult Black Oak usually have leaves near the base of the sucker which are simple in outline (PL 20, fig. 69), or .slightly lobed and with small teeth (PL 20, fig. 70). Succeeding leaves become rapidly more lobate and bristly (Fig. 69), but do not acquire the full character leaves of the species (PL 20, fig. 71) for a con- siderable distance from the base. As Emerson ('46) says of the form of the leaves in this species, " * * * on young and vigorous shoots, particularly on spi-outs from a stump, more nearly entire." Suckers from the base of the Scarlet Oak have leaves of the same form as in the Black Oak. In the above oaks, then, in suclcers and in vigorous growths from the stump, the leaves are more entire or simple than the typical leaves of the several species, thus mak- ing an approach to the simplicity of the seedhng in a greater or less degree. The fossil oaks of the Cretaceous (Lesquereux, '91), and Tertiary are simple in outline or slightly toothed. The seedUngs, suckers, etc., of the species discussed are therefore in their sim- pUcity comparable to ancient fossil allies. As the Swamp White Oak and Chestnut Oak are simpler in outline than the Black and Red Oak ty])es, they make a nearer approach to the characters of seedlings, suckers, and earl}^ fossil oaks, and may, therefore, be con- LOCALIZED STAGES IN DEVELOPMENT. 113 siderecl as the more primitive of our New England species. In tlie Live Oak of California [Quercus chrysolejns Lieb.),the Laurel Oak (Q. imbriearia Mich.) , and the Oblong-leaf Oak {Quercus oblongifolia Torr.), according to Professor Sargent ('91-97) , the typical leaves are entire, Iseing oval, oblong, or lanceolate in the several species. In vigorous shoots (also in the young of Q. chrysoJepis), he says the leaves are often dentate or lobed. These and similar species at first sight appear to be primitive oaks, on account of the simpUcity of their leaves, which in general are comparable to the simple leaves of fossil species and the young of specialized species. As vigorous shoots so frequently show reversionary characters, it suggests the view that these species may be simple from reversion not from primitiveness. A study of oaks from this point of view w'ould be interesting. MvRicA CERiFERA. Seedlings of the Bayberry [Myrica cerifera\j.) , yvavQ obtained from the Arnold arboretum. The cotyledons (PI. 19, figs. 52, 52a) are broad, spathulate, distally emarginate, non-petiolate, 5.5 mm. long, 3 mm. wide. The first nepionic leaves are 6 mm. long, 4 mm. wide, broadly spathulate, with three distal dentations. The first four leaves are of the same form only increasing in size. In later leaves additional mar- ginal indentations develop so that the leaf has a slightly lobate border; also a petiole develops, the blade extending down the petiole marginall}^ In the adult the leaves are very variable, being entire or slightly toothed (PI. 19, fig. 53). The midrib always extends at the tip as a slight mucronate point, in this feature resembling the tip of the eai-ly nepionic leaves. Very fre(^uently two ter- minal indentations occur, when the leaf may be closely compared with the first nepionic leaves ; frequently more indentations occur when in this feature it may be compared mth later leaves of the seedling. As a whole it may be said that the later leaves of tlie seed- ling are more deeply dentate and in this character more specialized than the leaves of the average adult. PiNUS EiGiDA. The Pitch Pine (Fbins rUjkla Mill.) presents interesting localized stages. In the seedling the cotyledons are strong and vigorous (PI. 21, figs. 72, 73) . They vary in number from four to seven. In 10(J seedlings counted, 18 had 4 cotyledons, 55 had 5 cotyledons, 26 had 6, and 1 had 7. Lubbock ('92) says tliat the Pitch Pine has from 4 to 6 cotyledons. The seven cotyledons found in one specimen are evidently some- what i-are, and may be anomalous for the species. The cotyledons are smooth and free from spinose growths, they are roughly triangular in section (PI. 21, fig. 73b), and acinninate distally. The form of these cotyledons is attributed to tlieir mutual contact and pressure during growth ; compare PI. 21, fig. 73b, with the White Pine cluster (PI. 21, fig. 81a, b), where five leaves are brought close together during growth, inducing a similar triangular form. Succeeding the cotyledons, the young Pitch Pine is densely 114 PvODERT TRACY JACKSON ON clothed with the nopioiiic or pnmary leaves. These leaves (PI. 21, fig. 73) are linear, acuminate distally, flattened on the inner aspect and curved on the outer (Fig. 73a). On the borders or edges are two rows of delicate saw-like s^iines, pointing distally. No third row exists as in adult leaves. From about 13 to 20 mm. above the cotyledons the bundles of leaves typical of the species begin to appear in the axils of the primary leaves (PI. 21, fig. 74). These bundles of leaves are usually in threes, but clusters are found in which two leaves occur instead of three ; they are not very common, however. The first two or three primary leaves which bear axillary clusters of needles (PL 21, fig. 74a) are long and acicular, as are preceding primary leaves. Succeetling primary leaves, however, rapidly shorten, while retaining the leafy character ; Init within a short distance are reduced and represented only by rather prominent scales (PI. 21, fig. 75), which subtend the leaf- clusters. During siicceeding growth to the adult, scales normally occupy the same position at the base of leaf-clusters. In the adult Pitch Pine the leaf-clusters are composed of three leaves, Ijasally sur- rounded by a sheath (PI. 21, fig. 75) . From their packed condition during gx-owth each leaf has assumed a form roughly triangular in section, ))ut curved on the outer side. On the three edges (two lateral and one median) a series of fine saw-like serrations have developed similar to those seen in primaiy and secondary leaves of other pines. Mr. Charles E. Faxon informs me that lie has seen a branch of this species in which all the leaves were in bundles of fives. As five leaves may be considered more specialized than three leaves, the typical condition in this species, such a branch may properly Ije consid- ered a progressive localized variation. When a young Pitch Pine has lost its leader or other prominent shoot, or, according to Emerson ('46) and Sargent ('91-97), on stum23s or after fire, a secondary sucker-like growth may be induced. These secondary growths are commonly vigorous (PI. 21, fig. 76 and fig. 77), and the scales have taken on a leafy expansion. The leaves are long, acuminate distally, flattened on the inner and curved on the outer side ; also they bear a row of saw-like teeth on the edges. They are thus seen to be closely similar to the nepionic primary leaves. These reversionary or localized primary leaves usually bear a bundle of leaves in their axils (PI. 21, fig. 70), but the l)undles in some cases may not develop, as shown in a few leaves in the figure. Raj^id growths from the stump may be entirely composed of primary leaves (PI. 21. fig. 77). the bundles not developing until later. Emerson ('46) says of the Pitch Pine, " Its stump throws up sprouts the spring after the stem has been felled. * * * The fallen trunk itself thi-ows out sprouts in the suc- ceeding summer ; and the Ijundles of leaves of both are remarkable for issuing from the axil of a single leaf, in the same manner as is observed in the young plant." 1 liave occa- sionally seen in a very Umited way similar growths on adult trees, where no apparent LOCALIZED STAGES IN DEVELOPMENT. 115 cause existed. When young seedling plants throw out lateral branches close to the ground, it is found that such branches for a certain distance are clothed with primary leaves, as is the vertical axis at the area where they originated. This is in accord with what has been observed in many other cases ; namely, that branches from nepionic areas are character- ized by nepionic leaves, as in Ampelopda tricuspidata, Negundo, ashes, oaks, Areca, etc. In the Pitch Pine, then, we find nepi(mic characters repeated in localized parts, either as branches from the nepionic area, or abnormal growths from any portion of the j^lants, but especially from stumps and young trees wliich have lost their leader or other prom- inent branch. While in normal growth the Pitch Pine loses its primary leaves very early, Sargent ('01-'97) says they may be retained for several years in the nut pines. In Prnus quadrl- foJia he says that after five or six years the primai-y leaves are shorter and begin to bear leaf-clusters in their axils. At Shady Hill nurseries plants of Pinus densijlora and P. massoniana, a foot or more in height, were seen which bore primary leaves with axillary leaf-clusters on all parts of the plants. Pixrs STEOBUS. In the White Pine {Pinus strohitsli.) , seedlings (PL 21, figs. 78-80) have from seven to ten cotyledons, in specimens examined at the Arnold arboretum and Shady Hill nurseries. Out of eleven seedlings, four have seven cotyledons, two have eight, two have nine, and three have ten cotyledons. The cotyledons are large and strong, as in the Pitch Pine, which they resemble. There is one marked ditference, however. In the White Pine the cotyledons are roughly triangular in section, and bear on their inner angle or ridge, also occasionally on their outer angles (Fig. 7'Ja) , fine saw-like teeth similar to the teeth of nepionic and adult leaves of this and other species. Similar teeth exist on the cotyledons of Putus montlcola Dougl. and Lamb, as observed at the Arnold arboretum. Serrations of the cotyledons of Pinus strohiis are mentioned by Dr. Masters ('91), but have not been dwelt upon before. Such teeth do not exist in the cotyledons of Pinus rigida, P. cembra L., P. resinosa Aiton, or P. imngens Lamb. These teeth of cotyledons may be considered as a case of accelerated development in which features usually appear- ing first at a later stage are shoved l)ack to an earlier, in this case an embryonic stage. Compare with Eucharidimn r/raiidiforum, Figs. 1 to 3, page 103, which during growth acquires nepionic characters in embryonic leaves. The succeeding primary leaves of the White Pine seedling are similar to those of the Pitch Pine, but are retained longer than in that species ; primary leaves are retained in the specimens observed until the plant is from 3.5 to 5 cm. in height, the end of the first year's growth. Then (PI. 21, fig. 81) the primary leaves begin to shorten, and bundles of five leaves, characteristic of the species, are borne in the axils of the shortened primary leaves which are soon replaced by small scales. Pi'imary leaves apparently never occur in later normal or abnormal growths of this species. 116 ROBERT TRACY JACKSON ON The leaf-clusters of the White Pine are enclosed in a ver}' short sheatli at the l)ase (PL 21, fig. 81a); from mutual pressure they have taken on a triangular form (Figs. 81a, b) , and the angles have saw-like teeth (Fig. 81a, c) , as in the Pitch Pine. In seedling jjines the duration of the nepionic character of primary leaves varies greatl}^ according to the species. Such nepionic characters may appear later in special localized growtlis under certain conditions, as described, but this again varies with species, not being a character common to all pines. PiNUS EESiNOSA. In seedlings of Piniis resinosa Alton, the features dii^er from those of other pines observed. The specimens were grown at the Arnold arboretum, one of them has 7 cotyledons, a second has 6 ; they are quite large, measuring 2 cm. in length. The primary leaves are unusually long, measuring 27-30 mm., and have fine ser- rate teeth on the lateral borders as in other species. The cluster-leaves are in twos, fiat on their apposed borders, curved on their outer sides, with rows of fine serrate spines as in primary leaves. The first cluster of leaves in the seedling is in the axil of a pri- mary leaf within 2 mm. of the cotyledons. Other axillary bundles occur throughout the length of the axis, which in the larger specimen measures 25 mm. above the cotyledons. The larger part of the primary leaves, however, do not bear axillary clustei's. This spe- cies is peculiar in the size and luxuriance of the primary leaves, in the early introduction of bundles of leaves, and in the relatively small number of such bundles to the number of primaries during early growth, Larix. Of the Larch I have only seen one young seedling which was kindly sent me by Mr. Charles E. Faxon. This seedling, Larix occidentalis Nutt. (PL 21, fig. 82), has five cotyledons, quite similar to those of the pine. Succeeding the cotyledons the nepionic leaves are thickly distributed on the ascending axis, but not so thickly as in the pines. These nepionic leaves are narrow, linear, acuminate distally. In the adult Larch, as represented by Larix europaea DC. (PL 21, fig. 8-3), the leaves are given off in dense clusters on the old wood. In the new wood of the current season's growth, on the other hand, there are no clusters, but the leaves are given off singly along the axis, as in the seedling. The cun-ent season's growth of this tree, then, resembles closely the nepionic growth of the seedling. A similar condition has been observed in other cases, where the new growth of the current year resembles the young. This is especially marked in Ampelojjsis tricus2ndata as described. • JuNiPERUS viRGiNiANA. In the Red Cedar {Juniperiis virginiana L.) the later stages in development and the features of the adult are very striking. Young seedlings were found in comparative abundance near adults in July and August, both at Martha's Vineyard and Milton, Mass. The seedling. Fig. 4, has two relatively broad, strap-shaped cotyledons, which are thin and very fugitive. While the number of cotyledons is variable LOCALIZED STAGES IN DEVELOPMENT. 117 in many conifers, I have seen no variation in tliis species, and two seem to be a constant character in the cypress family. The next or nepionic leaves differ from the cotyledons in that they are shorter, narrower, thicker, distally acuminate, and more permanent. The first nepionic leaves are a whorl of two opposite leaves, alternating with the cotyle- dons (Figs. 4, 4a). They are of the shape described, and about 7 mm. long. This two- leaved stage, in all the numerous individuals observed, is limited to a single pair of leaves. The next stage is introduced by a whorl of four leaves which are so arranged that they Jdniperus vikciniana. 4. Seedling, showing two long, broad cotyledons, o ; nepionic leaves; 1, whorl of two leaves alternating with cotyle- dons ; 2, whorl of four leaves alternating with cotyledons and first whorl of two leaves, followed by whorls of four leaves throughout this stage. X 1.6. -la. plan of arrangement of cotyledons and first two nepionic whorls. Milton, Mass. 5. Older seedling, showing two-leaved and four-leaved whorls, followed by a stage with three-leaved whorls as repre- sented in diagrams a, b, c. X 1-5. 6. Typical leaves of adult in alternating two-leaved whorls. X 1.5. a, plan of leaf arrangement. 7. Elongate vigorous growth of a terminal branch of adult, showing long, broad leaves arranged in three-leaved whorls. X 1.5. a, plan of same. 8. Abnormal tirfted ("bird's-nest ") growth of adult, .showing elongate leaves arranged in three-leaved or two-leaved whorls. X 1.5. Compare with Fig. 5. a, b, plans of same. Figs. 6-8, West Chop, Martha's Vineyard, Mass. alternate with the cotyledons and first whorl of two nepionic leaves (Figs. 4, 4a) . Thus up to and including the second nepionic whorl no leaves of the seedling are vertically superimposed. The second whorl of four leaves alternates with the first whorl and there- fore lies above the cotyledons and pair of first nepionic leaves. Other whorls of four leaves succeed the first two, occupying a vertical space of from 6 to 26 mm., and including 118 ROBERT TRACY JACKSON ON five or i*ix or more wliorls. The four-leaved whorls mark the second nepioiiic stage. While this four-leaved whorl is chai'acteristic of the vertical axis, such whorls have not been seen on any of tlie branches, even if given off very early. In Tliuya occidentalis, T. gigantea, and Libocedrus decurrens (PI. 22, figs. 86, 87, 89) the two cotyledons are also succeeded by one whorl of two leaves, then whorls of four leaves as described later. A third nepionic stage in the Red Cedar is marked by another change. The four-leaved whorl is aban- doned, and the leaves are arranged in whorls of threes (Fig. 5) . This occurs as early as 6 mm. above the two-leaved^ stage in some cases, or a little later in other cases. When the three-leaved stage is introduced, no more four-leaved whorls are formed. Occasion- ally branches on young plants have two-leaved whorls; these may be limited to two or three whorls only, or may be of greater extent. While such occur, they are less common, and three-leaved whorls are the characteristic feature of this period of develop- ment. The leaves are flat, narrow, acuminate, distally ending in a sharp point, and they are about 8-10 mm. long. This three-leaved acicidar character has been observed by several naturalists; it is retained until the tree attains the height of a foot or more, when adult characters appear, but the period of their introduction varies greatly in individuals. In the adult the typical leaves are arranged in pairs, altei-nating in suc- cessive whorls (Fig. 6). The leaves are blunt, scale-like, and closely imbricating. The above gives the features of leaves in the normal progressive development of the Red Cedar. In the adult, variations are striking, as described by Emerson ('46), Sargent ('91-'97), and others. In vigorous shoots (Fig. 7), given out mainly at the ends of branches, the leaves are broad, elongate, distally acuminate, and arranged in whorls of three or two leaves; but the former or ternate arrangement is perhaps the more common. The dense tuft-like growths of adult Red Cedars, called " bird's- nests," are still more obvious. They are caused by the growth of a fungus, Gymno. sporangium nidus-avis Thaxter ('90), and are common at points where an injury has taken place, as the cutting of a branch, on feeble or stunted trees, also on otherwise healthy trees. It is distinctly a pathologic character. On these growths the leaves are long and needle-shaped (Fig. 8) , and closely resemble the leaves of the young (Fig. 5) . The leaves on these tuft-like growths ma}' be arranged in whorls of twos or threes ; but^three-leaved whorls are present to a greater or less extent on all such growths and often predominate. At West Chop, Martha's Vineyard, Mass., the soil is excessively barren and the situation exposed. There the "bird's-nest" growths on the stunted cedars are very abundant. The leaves on these, as in the vigorous terminal growths, are largely arranged in whorls of three leaves. In Milton, Mass., where the soil is fertile, "bird's-nest" growths are less common, and both in these and in vigorous growths two-leaved whorls predominate over three- leaved whorls. At Cohasset, Mass., where the soil is good but the situation exposed, the LOCALIZED STAGES IN DEVELOPMENT. 119 ternate arrangement prevails in " bird's-nest " growths. On sickly branches or decrepit, dying trees similar needle-shaped leaves are often produced. I have seen old trees, almost bare stumps, but with the few remaining leaves of the typical awl-form charac- teristic of the young. There is, then, in the Red Cedar a clear case of pathologic local- ized stages which repeat youthful or primitive characters. It is a suggestive fact, as has been pointed out by Emerson ('40) and others, that the acerose ternate leaves seen in the young and localized pathologic parts of the adult Red Cedar are closely like the condition seen in the prostrate Juniper {Juniperus communis L.). This allied species, on account of its awl-shaped, bristly, ternate leaves and prostrate habit, we may suppose to be either a primitive or a degradational species, perhaps more likely the latter. The fastigiate form of ./. communis, or Irish Juniper, has similar ternate bristly leaves. Another species, Juniperus calif or nica Carr., has ternate leaves, but appressed, not elongate and awl-like (Sargent, '91-'97). Tlie earliest known fossil cedars from the Cretaceous have acerose, ternate leaves. These ancient, primitive types apparently represent the ancestral form from which the acerose, ternate leaves of the young Red Cedar are derived, and to which the similar leaves of pathologic growths of adults are reversions. Junip)erus communis has retained the primitive acerose, ternate type, or else has reverted to it. Juniperus californica has retained the primitive character of ternate arrangement of the leaves, but has appressed leaves, and in this feature is in accord with the progressive species of the genus. Juniperus monospermum. Of Juni2')erus monospermum Engel. I had the oppor- tunity of seeing six seedlings at the Arnold arboretum. The seed were collected in Manitou, Col. All of the seedlings had two cotyledons, succeeded by a whorl of two leaves, again succeeded by whorls of four leaves as in J. virginiana. In five of the specimens, four-leaved whorls continued to the top of the main stem (a few inches only), but the leaves of the lateral branches were all in whorls of threes. In one of the specimens there were three-leaved whorls on the upper part of the main stem, showing a transition similar to that shown in Juniperus virginiana (Fig. 5) . Thuya occidentalis. An interesting series of seedling Arbor Vitae {Thuya occiden- toZis L.), was sent me from Beedes, Adirondacks, N. Y., by the kindness of Miss Marian C. Jackson. Only one of these was young enough to show cotyledons and the first suc- ceeding leaves. In this specimen (PI. 22, fig. 84) there are two strap-shaped cotyledons. The first nepionic leaves are a whorl of four leaves, 4 mm. long, alternating in position with the cotyledons, as shown diagrammatically in PI. 22, fig. 84a. The second whorl is also composed of four leaves alternating with the first whorl. Succeeding leaves in this and most specimens are in whorls of two leaves, no four-leaved whorls occurring in later growth, and no three-leaved whorls appearing at any stage. 120 ROBERT TRACY JACKSON ON Two specimens of seedling Arbor Vitae, growing under a hedge in cultivation at Andover, Mass., were collected by Mi's. R. T. Jackson. In both specimens, the first leaves succeedhig the cotyledons are a pair of opposite leaves. In one of the specimens (PI. 22, fig. 86) , the second whorl is four-leaved, and succeeding leaves ai'e in whorls of threes on the main stem; but a lateral branch has leaves in twos only. The second specimen has three leaves in the second whorl ; but it is evidently a four-leaved whorl in which one leaf is suppressed, or lost in early growth, as a space exists where it should occur. Later leaves of this specimen are arranged on the main stem in irregularly placed threes, they not being sufficiently in the same planes of insertion to call them whorls. On a side branch the leaves are in twos as usual. In a seedling figured in Professor Sargent's Silva, there are two cotyledons succeeded by a whorl of two leaves, then by several whorls of four leaves. While considerable variation occurs, it is evident that the typical seedling has two cotyledons succeeded by a whorl of two leaves, then by one or more whorls of four leaves succeeded by the two-leaved whorls characteristic of this type. The variations are no greater than those described later in Lihocedrus decurrens. To return to the specimen of Arbor Vitae (PI. 22, fig. 84), the narrow, elongate, primary leaves are maintained to the tip of the main stem, and the same feature exists in all the other seedlings; concurrently lateral branches have already acquired leaves which are a close approach to the adult condition. This is a notewoi'thy feature, for in many conifers, Pinus rirjida, Fig. 74, Libocedrus, Fig. 89, the main stem develops mature features first, or at least as soon as lateral branches. On the side branches (PI. 22, fig. 84) , at their inception, there are one or more pairs of typical primary leaves ; but these soon give place to leaves which are shorter, appressed, scale-like. Succeeding pairs of leaves (PI. 22, fig. 84b) diflier, as do adults, in that the marginal leaves are narrow, embracing by their apposed edges the median pairs which are flattened, broadened and embraced by the distal borders of the preceding marginal pair. These leaves of young branches are acuminate distally, with free tips, whereas in the adult (PI. 22, fig. 85) the tips of the leaves are blunt and appressed. It is an interesting phylogenetic fact, that in fossil Thuyites from the Jurassic, the tips of the leaves are acuminate and distally free as in the young of our species (Fig. 84b) . The features as described are characteristic of 35 out of 40 seedlings of this species from the Adirondacks; 5 specimens only showed a variation. In three of these the leaves are in whorls of threes up to within two or three whorls of the introduction of " charac- ter " leaves, when two-leaved whorls appear. Two other specimens have respectively 14 and 17 whorls of three leaves each, above which the leaves are in twos as usual. It is to be remembered, as stated, that only one specimen showed cotyledons and first suc- ceeding whorls. This taking on of a three-leaved whorl in a type which is so strongly LOCALIZED STAGES IN DEVELOPMENT. 121 two-leaved is striking. On leading shoots of adult Arbor Vitae pointed leaves some- times occur, often a quarter of an inch in length (Sargent, '91-97) , showing localized reversions to the youthful and ancestral condition. These elongate leaves are not so common or so marked in character as are the somewhat similar reversionary leaves of the Red Cedar. Thuya gigantea. The seedling of the western species of Arbor Vitae {^Thuya giyantea Nuttall) differs markedly from the seedling of T. occldentalis. In tliis species (PI. 22, fig. 87), as shown by two specimens, there are two cotyledons 7 nnn. long, 2 mm. broad. The first nepionic leaves are a single pair, very short, 2 mm. long, lying close above the cotyledons, and alternating with them in position. In the sec()ut the same period of growth, both on the terminal shoot and side branches. Side branches bear a few whorls of primary leaves in fours: but ver}^ soon the later form of leaf is introduced. The leaves of this late nepionic stage are appressed, sharp-pointed (PL 22, fig. 89a), arranged in four-leaved whorls, the marginal leaves narrow, elongate, and embracing the median pair. The arrangement is similar to that of Thuya, Fig. 84b, but with the essenti;il difference that in Thuya the leaves are two-ranked and marginal leaves embrace the edo;es of the leaves of the next succeeding wdiorl. In adult Libo- cedrus decurrens (Fig. 90) the leaves are appressed, blunt distally, and in four-leaved whorls as in the later stages in the j'onng. The variations in the seedlings are ([uite striking. Out of twenty-five specimens, 22 conformed to the type as described. Two specimens had skipped the two-leaved stage, the first whorl of leaves after the cotyledons being a four-leaved whorl (Fig. 11, and PI. / / 7 30 CCTc slZ^C u 10 ' CCZ5 xr~^ C- LllSOt'EHKlS IIECIHIIKXS. 9-11. Plan.s of ccimiiarativp pliyllotactic arrangement of cotyledons, c, and first two whorls of nepionic leaves, 1, 2. 9. Typical arrangement, in which there are two leaves in the first nepionic whorl and four leaves in the second nepionic whoi-1, seen in 1*1. 22, figs. 88, 80.] 10. Abnormal arrangement in wliicli tliere arc only two leaves in tlie second nepionic whorl, seen in PI. 22. fig. 92. 11. Abnormal arrangement in wliicli there are four leaves in tlie first as well as in the second nepionic whorl, seen in ri. 22, fig. 91, 91a. 22, Figs. 91, 91a) . It is noteworthy in botli of these specimens that the two leaves of either side are fused proximally and for a slight distance (2 mm.) upward from their point of insertion on the stem (Figs. 91,91a). This suggests the view that the four- LOCALIZED STAGES IN DEVELOPMENT. 123 leaved condition of this individual whorl is morphologically a splitting of the normal two leaves characteristic of this stage. In relative phyllotactic arrangement this first whorl in relation to the cotyledons occupies a similar position to the second whorl of the normal growth; compare Figs. 9 and 11. The second whorl occupies the same position as the third whorl in nornuvl growth. The second specimen mentioned as having a four-leaved whorl succeeding the cotyledons has an arrangement as in Fig. 91, excepting that the third whorl above the cotyledons consists of an isolated two-leaved whorl and is the only such variation observed. A third specimen showing variation from the normal is represented in PI. 22, fig. 92. In this all the primary leaves are two- instead of four-ranked ; but the later char- acter leaves are four-ranked as usual. The first pair of leaves alternates with the cotyle- dons as usual. The second pair alternates with the first and overlies the cotyledons, Fig. 10. Succeeding pairs of primary leaves are regularly alternated (PI. 22, fig. 92). The phyllotactic arrangement of leaves in the normal and aberrant seedling is seen by com- paring Figs. 9-11. The varying arrangement of the leaves in these several seedlings shows how sensitive the growth force of these plants is to the relations of environment, each set being arranged so that the first whorl alternates with the cotyledons and the second whorl alternates with the fii'st, covering the cotyledons or not as the case may be. Youthful characters are considered of phylogenetic significance, barring larval adaptation and skipping of stages by acceleration of development. It is seen that in the young of Juuiperus, Thuya, and Libocedrus, succeeding the cotyledons there is typically a whorl of two leaves, succeeded by one or more whorls of four leaves. In Ciqyresi^us lawsoniana Murray, according to the figure in Professoi- Sargent's Silva, the nepionic leaves are all in whorls of fours. These should point to primitive radicals which in the adult condition are characterized by a similar arrangement. Of the two- leaved stage no ancestral form can be pointed out at present. It would seem that Thuya, Cupressus, and Juuiperus may be considered degradational types which in the adult in t3q:)ical S23ecies have reverted to the two-leaved type characteristic of some ancestral form, as evinced by stages of their own young. The degradational character of these genera is evinced by the depauperate scale-like leaves as well as the two-ranked arrangement. The adult representative of the young four-leaved stage of these genera, it seems, may be represented by the type Libocedrus or more properly a predecessor of the same, which had fiDur-ranked needle-like leaves. Libocedrus is not known earlier than the Cretaceous, and these old forms are quite close to the modern representative, but its four-ranked arrangement is so striking that it would seem to indicate that it is in the line of ancestry of the associated genera. 124 ROBERT TRACY JACKSON ON Palms. Amongst palms many species present interesting features of localized stages in development. I have studied the development of seedling palms of thirty-seven species, and from puljlishcd figures of von Martins and others know something of the early chai-ac- ters of about forty-five species, distributed tlirough twenty-eight genera. Seedlings of all species have simple, early seed-leaves, and these are always one of two types. The first and most primitive type of seed-leaf is elongate, lanceolate, or oval, ternunating more or less acutely, and with a longer or shorter rachis, usually long. This type is seen in Latania (PL 23, fig. 9i), Corypha (PL 23, fig. 104), Cocos (PL 23, fig. 102), Phoenix (PL 23, figs. loo. 103, lO.lal and many other genera. The second type of nepionic or seed-leaf is similar to the lirst, except that it is distally cleft. It is characteristic of ChrysaUdocarpus (PL 23, fig. 95), Kentia (PL 23, fig. 9G), Caryota (PL 23, fig. 98), and of many other genera. Very .young specimens of genera which have distally cleft leaves or exce2)tional individuals show a transient distal fusion of the apices of the leaf, as in Kentia (PL 22, fig. 96), demonstrating that the cleft type is oidy a modification of the first or entire type. In some types, as Stevensonla grandlfolla J. Dune. (Phoenicojjhor^nn secheUancm H. WendL), which have distally cleft leaves, the first leaves are entire, the cleft character appearing later (third leaf of the specimen in hand). This is a further demonstration of the primitive nature of the entire type. In some eases the acuminate tips of seed-leaves may l)e modified by distal truncation, as in ArciKjd xacchai-ifera Labill. and Caryota cumlngii IjodiA. (C »re».s Blanco.) (PL 23, fig. 98) . A fossil species from the Cretaceous (Laramie), Oreodoxites 23licafus Lesq., closely resembles the form of tlie more primitive type of seed-leaf, and hardly differs, except in its greater size, from the young leaf of Corypha (PL 23, fig. 104). Other fossil palms from the Cretaceous and Tertiary belong to genera the yoiuig of which is characterized by the entire type of leaf. In Latania covDiiersoji'u J. F. Gniel. (L. t>orho»ica Lam.), the seed-leaf is ovate, lan- ceolate (PL 23, fig. 94); during growth the later leaves l)ecome relatively broader, mitil, by distal tension, splits take })lace (PL 23. fig. 9;i), and in tlie adult the leaf is a ([uite broad, fan-leaf type. The development of other fan-leaf palms, as Sabal, Washingtonia, Chamaerops, and Ra])his, is similar to that of fjatania. The angle of divergence of the rays varies directly with the relative length of the laehis and the amount of leaf-tissue formed. In Phoenix ca/tarienxis llort. the first seed-leaf (PL 23, fig. 100) is elongate, lanceo- late. The first leaves of PhocJtix rupkola T. Anders, are similar; in later added growth the leaves, while retaining their simple outline, become relatively broader, with an elongate rachis, as shown in leaf 1, PL 23, figs. 103, 103a. During growth, as new leaves are added, the rachis elongates, the leaf-tissue on the sides becomes relatively reduced, and LOCALIZED STAGES IN DEVELOPMENT. 125 pinn.ae result from the splittin.i;' apart of the leaflets, as shown iu leaves 2 and 3 of Fig. lO.'i. The leaf of the adult is similar to the last formed leaf in PI. 23, fig. 103, except in the increase in size, and in the nuuilier of pinnae, and in the relative reduction of the terminal leaflet. In Cocox iiTedde/itnin Weiidl. (PL 23, figs. 10], 102). the development is similar to that of Phoenix. In Cdnjota ciimiiigii Lodd. (C. iirciix Blanco) (PI. 23, figs. 97-98), the early seed- leaves are deeply cleft, more so than in the seedling of any other palm known, and the leaf is distally truncate and serrate as if snipped with scissors. As the plant grows older, the leaves become pinnate (PI. 23, fig. 97), the distal leaflet resembling the simple early leaf. Adult leaves are similar to this early compound leaf, except in size and the increased number of tiie leaflets. This is, perliajjs, the most dift'erentiated type of nepionic leaf seen in palms, and in its cliaracters shows a markedly accelerated development, ('ariiofd riniij)]it(iii(i Mort. is similar to ('. ciniiiiH/ii in early characters. In palms with })innately compound leaves, in all cases where the adult and young are known to me, the distal leaflet of the adult leaf corresponds closely in form to the whole of the early nepionic leaf. This is the case in several species each of Phoenix (PL 23, figs. 100, 103), Cocos (Figs. 101, 102), Caryota (Fig. 97, 98), Chrysalidocarpus (Fig. 95), Kentia (Fig. 9C) and other genera. In the growth of a pinnate-leaved ])alni, when a new leaf first appears, the pinnae cling together laterally on their outer margin and to the distal leailet, in such a way that the whole leaf simulates the entire type and demonstrates the simple dynamic genesis of this type of compound leaf from an ovate leaf like that of the young. This is shown well in Dlploihemhim riKty'dliiutm Moi't. (PL 23, fig. 99), also in part of the leaflets of Phoenix (Fig. 1U3, leaf 3) and Cocos (Fig. 101). A similar clinging may be seen in palmate palms (PL 23, fig. 93) . An elongation of the rachis with attendant reduction of leaf-tissue induces the pinnate type. A shortening of the rachis induces the palmate type ; Sabal, Latania. An extreme shortening of the rachis with abundant leaf develop- ment may even induce a form in whicli the leaf is radial from a central point in the rachis; some species of Chamaerops. In the development of a leaf, then, there is in this localized part a repetition of features seen in the young. Also the distal tip of pinnate leaves repeats the form of nepionic leaves. Some palms sucker from the base, and in such suckers we might expect to find local- ized stages in development, as is the case. In Ra/)hi>i ffabef/lfoniiix L'flerit., a fan-leaf palm, suckers from the base have .simple ovate leaves like (PI. 23, Hg. 91) and only in later growth are the typical fandeaves of the species acquired. I have not seen seed- lings of Ji. JliiheJ/lfoniils, but the suckers repeat the form of seedlings of KapluH lannUls var. eh'(j(tiis and allied genera so closely that in leaf cliaracters they are inseparable. 126 ROBERT TRACY JACKSON ON In Chrysalidocnrpus Jutef oJ onk-a, Fig. 42, Tecoma radlcam, Fraxinus americana, Fig. 47, Sm^sfifrm msm- fras, Hicoria ovata, Fig. CO, PJatanm^ occideutaHs, Figs. 55, 56, Quercns, several species. Figs. 63, 65, 69, 70, Pinus rUjlda, Fig. 77, Paphisj!(d}eIUforiiiis, and Arecn htfescois. While suckers repeat nepionic characters, they are often highly accelerated in their devektpment, so that only one or two, or a few, leaves at the base are reversionary. Also there may be considerable diti'erence in the degree of reversion in individual suckers, ;is in the Trumpet Vine, White Ash, and Black Oak, Figs. 69, 70. Suckers may i)resent more primitive characters than the seedling, as A'ddiifJui^^ (jhmduloxd, Fig. 14, in which the first leaves are simpler than the first nepionic leaves of the seedling. As far as observed tb.is is miusual. Considerable variation often occurs in suckers, as noted in the White Ash, Black Oak, and Aiiauthus. While this is more or less confusing in attempting to correlate sucker growth with nepionic and ancestral characters, it is not more so than tlie variations often found in seedlings, as especially noted in the cases of Thuija ocvhh-utalts and Libocednis deciirrens (p. 119, 122) . Reversionary or localized stages are marked features of aljuormal growths, as "birds- nest" growths of the Hed Cedar, Fig. 8, p. 117, suckers of the Pitch Pine, Fig. 77. They are frequent in vigorous growtlis, as terminal shoots of the Red Cedar, Fig. 7, page 117, and Red Maple and Pfdtaiius occidental^, Fig. 58. Reversionary features also often occur in feeble or retarded growths, as seen in growths formed late in the season, or on injured branches. Tulip-tree, Ailanthus, Acer ritbnim, A. jjeiuisj/lrniiicuiu, A. spica- tum, the White Ash and Red Ash. They may occur in sickly or old age growths, as in the Red Cedar. It seems that the leaf itself has an ontogenesis repeating more or less fulh" tlie ontog- eny of the young. In the development of the leaf the distal part is usually formed first, and during growth the proximal partsare progressively added. If this is true, wt' siiould expect to find that the distal ])art of the leaf woidd be the simplest, most primitive part. 140 ROBERT TRACY JACKSOX ON iiiid hear more or less resemblance to the early nepionic leaves of the seedling. Snch is louiid to be the fact in many cases, as Aqnilegia, Fig. 17, Liriodendron, Fig. 12, Aihutf/uis (jiajtdiilosa, Acer, several species. Fig. 29, jVer/mido aceroides freqnently. Fig. 30, Iledera helix, Fig. 44, Tecoiufi rtidicdiis. Fraxinus, several species. Fig. 48, SriKnafras xassafras, •Fig. 51, Hicorhi oratd. Fig. (Jl, C(jcos, I'hoeni.v, Kentia, Areca, ('aryota and many other pinnate ])ahns, Pigs. Kll, 10>;. !l."). !I7. If the distal end of the leaf ivpeats ne[)i()iiic characters, then types which hiive com- pound imparipiiniate leaves should have a shnple nepionic leaf, and such is the case in species observed, the exceptions occurring only wlien the first leaves bv accelerated ^) . ()\\ the same liasis. com- pound paripinnate-leaved types should have compound paripinnate nepionic leaves with two or more leaflets ; sucli is found to be the case in most types (Gleditschia, Fio-. 39) bnt Sesbania, as noted (p. 103), is an exception, having first a shnple nepionic leaf. It' the tip of a leaf is the simplest part, then increased complication should take place pi-oximaily. This is obviously the case in all impari[iiiniate leaves. It is markedlv the case in l^tcrh (iqiidhid and many other ferns. In some cases the [>i'oximal portion of the leaf is the simplest. This is n(.)tal)ly the case in (Tijimtix'hidii^ disin/s. Fie. 37 wliere latei-al dixisions are reduced to single leaflets. This simpler or last formed portion is com l)arable to the simple condition of the sucker and probably of the seedling. To compare with ontogenies of whole organisms: adults or later periods of growth are often simpler than the young in degraded animals, as Ostrea, Baculites, parasitic Crustacea. Adult plants may also be simpler than their own j'onng, AvqjeJopfds tricKSj^idata, Fio-s. 20, 22. The tip of the leaf is sometimes the specialized portion, Dionaea, Cohaea scandens. If there is ontogenesis of individual leaves, then an}- cause which interfered with such development would tend to produce an imperfect, innnature, primitive, or reversion- ary leaf. Such reversionary, more or less isolated leaves are found in Liriodendron, Am- pcJops'm qnuiquefolUi, N('(jinid() oceroides, Gleddschia /rica/d/ios, Plafaiiiis occidentcdix Hicorifi oi-dtd, Fj-d.riiuis d)nerica)id, F. pithei^cens, and pinnate palms. In such ontoo'enies of in-dividual leaves in degraded species we may expect to find localized evidence of ances- tral moi'c specialized forms. Such occur in the occasional compound leaves of Frd.riinn^ uiioiiidld, which species is characterized by simple leaves. In a word, primitive or reversionary features in adult plants mdy be looked for in such localized parts as suckers, weak, senile, or abnormal growths, in the distal and ])rox- imal parts of leaves, or in muisual individual leaves. How general such localized primitive features or stages in development will prove to be, is uncertain. To proAe that they do sometimes exist is all that is attempted here. New varieties and species in the state of nature are generally supposed to oritdnate LOCALIZED STAGES IN DEVELOPMENT. 141 bjsexiiiil reproduction. The question arises, could such new forms originate from such variations as are seen in locahzed stages in development of either a progressive or regres- sive character. It is probable that variations may at least occasionally originate in this manner in the state of natui-e. Professor Bailey ('96) states that seedlings of varieties which have originated from bud-\ ariation are quite as likely to reproduce the variation as those raised from varieties originated by seed-variation. It is (piite possible, therefore, that indiviihials wliich diifer from the type originated from seed borne on localized branches which dilfered in the same direction. In plants, variations in localized areas have been noted in many cases, as in the Tulip- tree, Sassafras, Platanus, Pitch Pine, Red Cedar, etc. In animals, areas of localized varia- tions have been noted in Palaeozoic Echini. Such variatitjns in localized parts as observed are not haphazard and heterogeneous in kind. They are all perfectly definite, being either atavic or progressive variations, and can be correlated with similar characters seen in the young or in fossil representatives, or else in more advanced species of the group to which the animal or plant belongs. Occasional variations cannot be correlated with the ontogeny or phylogeny of the type, such as the split leaves in Libocedrus, Fig. '.>1. These may properly be considered as monstrosities, comparable to fan-tail pigeons, top-knot fowls, double flowers, cut-leaf birches, etc. In aninuils which reproduce asexually by budding, as Hydrozoa and Actinozoa, it seems that the bud may be considered a locaUzed stage (Galaxea, PI. 24, figs. l()(j-l()'.)) . The bud has not the stages seen in early embryonic development from the egg, but re- peats in general the later stages seen in such an ontogeny. A bud is not a new individual in the full sense of the word, but is an outgrowth from an older individual by a special localized development. In animals which, during growth, acquire an addition of similar parts, there is often a strongly marked ontogenesis of such parts, which is parallel to the condition seen in the young or in simpler, less specialized, and ancestral types. Echinoderms, which during growth acquire additional plates, in certain cases show evidence of such localized ontogen- esis. Such are the addition of new plates to the stem in the recent crinoids, Metacrinus, Fig. 124, and Pentacrinus, the young newly added plates being comparable to the plates of the whole stem in Jurassic representatives, Fig. 125. In the Echini (Strongylocentrotus, Figs. 112-116, and Arbacia, Figs. 110-111), new plates are added at the dorsal" border of the corona. Such young plates repeat the char- acter seen in all the plates of a very young individual, and are similar to the plates of Cidaris, which is a primitive type in this group. As there is an ontogenesis of the indi- vidual plate, so a series of successively older plates presents successive phases of ontogenies ; as a result, in passing from the dorsal Ijorder of the corona ventrally, a series of stages 142 EGBERT TRACY JACKSON ON may be traced wliicli, in general, can be correlated with a similar series in young develop- ing individuals. In the Palaeozoic echinoid Lepidechiniis the new plates added at the dorsal border of the corona are ditferent from the older plates in the same specimen, and present features similar to those seen at the same area in allied less specialized types. Localized stages in development as represented in budding animals and echinoderm plates, are seen only in the youth of the bud or jtlate, and during growth are wiped out by changes in the growing part. In the following cases of ornaments of mollusks and septa of cephalopods a different condition exists. The localized stages are perma- nently fixed in the part and are not capable of modification during further growth of the animal. Beecher (98) has pointed out that the spines of radial plications which originate by inter20olation in certain brachiopods and mollusks, repeat in their inception and subsequent growth the characters seen in early stages of older plications which originated earlier in the life of the individual; Spondylus, Figs. 12-13, page 133. In the septa of ammonites that portion of tlie septum which is nearest the umbilicus is the simplest portion, and repeats more or less fully the condition of the whole septum of the young and of ancestral moi'e primitive types; Placenticeras, Figs. 117-121. As the septum is followed from the umbilicus outward to the ventral border a progressively increasing complication takes place, which is parallel to the progressive complication seen in passing from the young to the adult and concurrently from the geologically earlier to the more recent types. An important feature in this case is the fact that the whole septum is built at one time, representing a single period of growth. Its simpler and more complicated portion, therefore, being built at one time, differ from the simple and more complicated condition of the individual plates of Arbac^a and Strongylocentrotus (PI. 24, figs. 110-116), in whicli ditt'erentiation takes place during the growth of the plate as described. In the trilobite, TrUirthrns beckii, localized stages seem to be expressed in the distri- bution of the ventral appendages, which posteriorly are )n-oad and essentially primitive, Avhile anteriorly they are narrow and specialized (Beecher, '90) . In general, it may be said of localized reversionary stages of adult organisms, that they do not repeat embryonic characters, but eai'lier or later nepionic or neanic characters, as noted in numerous cases of plants and animals. Tlie chief interest of localized stages in develo])ment is the fact, that they call for a comparative study of all parts of the organism, young, adult, and old, and a coi'relation of these comparisons with the characters in other living and fossil species. LOCALIZED STAGES IN DEVELOPMENT. 143 Literature. Agassiz, Louis. '63. Methods of study in natural history. Boston, 180.3, .319 pp., figs. Bailey, L. H. '96. The survival of the unlike. New York, 1890, 515 pp., figs. Beecher, Charles Emerson. '90. The morphology of Trlarthrus. Amer. journ. sci., ser. 4, vol. 1, p. 251-256, pi. 8. Beecher, C. E. '98. The origin and significance of spines, a study in evolution. Amer. journ. sci., ser. 4, vol. 6, 1 pi. figs. Clark, H. James. '65. Mind in nature. Boston, 1805, 322 pp., figs. Deane, Walter. '96. Notes from my herbarium, V. Bot. gazette, vol. 21, p. 211-214. Emerson, George B. '46. Report on the trees and shrubs of Massachusetts. Boston, 1846, 549 pp., 17 pi. Second edition, Boston, 1875, 624 pp., 145 pi. Holm, Theodor. '90. Notes on leaves of Liriodendron. Proc. IT. S. nat. mus., vol. 13, p. 15-35, pi. 4-9. Hyatt, Alpheus. '97. Cycle in the lite of the individual (ontogeny), and in the evolution of its own group (phylogeny). Proc. Amer. aoad. arts and sciences, vol. 32, p. 209-224. Jack-sou, R. T. '96. Studies of Palaeechinoidea. Bull. geol. soc. Amer., vol. 7, p. 171-254, pi. 2-9. Jackson, R. T. '98. Localized stages in growth. Proc. Amer. assoc. adv. sci.. vol. 47, p. 359-360. Jackson, Robert Tracy, and Jaggar, Thomas Augustus, Jr. '90. Studies of Melonites multiporus. Bull. geol. soc. Amer., vol. 7, p. 135-170, pi. lycsquereux, Leo. '91. The flora of the Dakota group. Monogr. U. S. geol. surv., vol. 17, 400 pp., 06 pi. Lov6n, Sven. '92. Echinologica. Bihang till kongl. svensk. vetenskaps-akad. handl., Stockholm, Bd. 18, afd. 4, 74 pp., 12 pi. Lubbock, John. '92. A conU-ibution to our knowledge of seedlings. 2 vols. New York, 1892, 608, 040, 084 figs. Masters, Maxwell T. '91. Review of some points in the comparative morphology, anatomy and life-history of the Conifcrae. Journ. Linn. soc. London, botany, vol. 27, p. 226-332, figs. 1-29. Sachs, Julius. '75. Text book of botany. Oxford, 1875, 858 pp., 461 figs. Sargent, Chax'les Sprague. '91-'97. The silva of North America. Boston, 1891-97, 11 vols., pi. Smith, J. Perrin. •98. The development of Lytoceras and Phylloceras. Proc. Cal. acad. sci., ser. 3, geology, vol. 1, p. 129-160, pi. 16-20. Strasbiirger, E., Noll, F., Schenck, H., and Schimper, A. F. W. '98. A text-book of botany. (Translated by H. C. Porter.) London and New York, 1898, 632 pp., 594 figs. m ROBERT TRACY JACKSON ON Thaxter, Roland. '91. Tlie Coniiectieut species of Gymnosporangium (cedar apples). Bull. 1(17, Conn, agric. exper. .station, p. 1-6. Wachsmuth, Charles, and Springer, Frank. '07. The North American Crinoidea Camerata. Mem. mus. comp. zool., vol. 20-21, 837 pp.. 83 pi. Ward, Lester F. '87. Types of the Laramie flora. Bull. 37, U. S. geol. surv., 3o4~pp., 57 pi. Ward, L. F. '88. The palaeontologic history of the genus I'latanus. I'roc. U. 8. nat. mus., vol. 11, p. .3!)-42, pi. 17-23. Zittel, Karl A. '76-'90. Handbuch der palaeontologic. Jliinchen und Leipzig, 1870-00. (Invertebrates and plants, 3 vols., 261(i pp., 2100 figs. J. Explanation of Pi.ate.s. C = Cotyledons. Individual leaves or whorls of leaves are frequently numlicred a.s an aid to description. PLATE 16. LiRIODENDKON TULII'iriCU.V. Fig. 1. Typical four-lobed leaf of adult, xi. 1'. 04. Fig. 2. Typical six-lobed leaf of adult, representing liy dotted lines llie method of droiijiing ontof parts in the fonnatinn of a reversionary leaf. A slightly regressive leaf omits two basal lobes a-b. a more regressive leaf omits four basal lobes c-d, a highly regressive leaf is rounded distally e-f. Xi- P. 0.5. Fig. 3. Leaf with eight lobes, an extreme, progressive variation. X {. !'• 04. Fig. 4. Reversionary leaf of adult ; compare Fig. 2 c-d. X-i- P. 04. Fig. 5. Early uepionic leaf, with rounded angles and truncate end. X\- (lloliu, "Oo). P. 05. Fig. 6. Later nepionic leaf of a .seedling showing angles sharpened. X\. (Holm, '00). P. 95. Fig. 7. Reversionary leaves on mutilated branch of adult ; compare Fig. 2 a-b, and e-f. Xi. !'• 04. Fig. 8. Seedling .showing cotyledons and two nepionic leaves. X\- P. 03. Fi". 0. Branch showing progre.ssive variation of an abnormal tree in which P'ig 10 is the typical leaf. Leaf 1 has iwo slight lateral lobes, leaf 2 has four slight lateral lobes, leaf 3 is regressive, comparable to Fig. 5. Xi. 1'. 05. Fif. 10. Typical leaf of a highly reversionary tree, comparable to nepionic leaf Fig. 6. Figs. 9-10 from tree in Arnold arboretum. X i- I*. 95. Fi". 11. Seedling .showini; cotyledons and .succeejling nepionic leaves, leaf 3 has developed slight lateral lobes. Xi. P. 93. Fig. 12. Typical .six-lobed leaf of adult. Xi. P. 04. Fi". 13. Reversionary branch .showing leaves which in their simplicity ap])roach the condition eharacteri.stic of the young ; compare with Fig. 11, also Fig. 2 a-b and e-f. X i. (Figs. 4, 7, 12, 13 are leaves from one tree. Cultivated, Dor- chester, Mass. Figs. 8, 11, .seedlings, Milton, Mass.) P. 04. AlT.ANrilUS GI.A.NOri.OSA. Fii;. 14. Sucker from root of adult tree, all leaves alternate; 1-3 simple, 4. trifnliohite, 5-0 4uin.incfolinlatc. Culti- vated. X i. P. 06. Fi". 15. Seedling showing romided cotyledons, the first nepionic leaves are opposite, later leaves alternate, all trifolio- late. Leaflets of leaves 3-4 have marginal notches. Cultivated, x A. P. 'S>6. LOCALIZED STAGES IN DEVELOPMENT. 145 Aquilegia canadensis. Fig. 16. Seedling showing cotyledons and trifoliolate first nepionic leaf. XU- P. 93. Fig. 17. Leaf of adult, the distal end with its major indentations is comparable to the whole nepionic leaf. Xj. Figs. 16-17 cultivated, Dorchester, Mass. P. 93. Rhus toxicodendron. Fig. 18. Seedling showing cotyledons and nepionic leave.«, the first two opposite, succeeding leaves alternate, all tri- foliolate with lobes in the proximal leaflets. West Chop, Martha's Vineyard, Ma.ss. XI- P. 97. AmPELOPSIS QriNQUEFOLIA. Fig. 19. Seedling .showing ovate cotyledons and three nepionic leaves, all alternate, 1,2, trifoliolate, but leaf 3 is ijuiniiiie- foliolate, like the adult. West Chop, Martha's Vineyard, Mass. Xh- P. 97. Figs. 16-17 drawn by_Mr. J. H. Emerton ; others by the author. PLATE 17. Ampelopsis triccspidata. Fig. 20. Seedling showing broadly ovate cotyledons and alternate, trifoliolate, nepionic leaves. Xl. P. 98. Fig. 21. Tip of an older seedling. Leaf 1 is trifoliolate, as are all the leaves proximally in this specimen. Leaf 2 has a lateral leaflet on one side. Later leaves are all unifoliolate, dentate. Xj- Figs. 20-21, Shady Hill nursery. P. 98. Fig. 22. Typical unifoliolate, trilobed leaf from old wood of adult. Compare Fig. 25b. XL P. 98. Fig. 23. Trifoliolate leaf from base or nepionic area of adult vine. Compare Figs. 20 and 25a. Xl- P. 98. Fig. 24. Unifoliolate, dentate leaves from wood of current season's growth. Compare Figs. 21 and 25c. Xi- Figs. 22-24 ail from one vine, cultivated. Vineyard Haven, Mass. P. 98. Fig. 25. Diagi-am showing distribution of types of leaves in adult vine raised from seed. Area a, near base of vine, leaves trifoliolate ; area b, old wood, leaves unifoliolate, trilobed ; area c, wood of current season's growth, leaves unifoliolate, cordate, dentate. Compare with Figs. 20-24. P. 98. Acer rubrum. Fig. 26. Tip of branch of adult, with young leaves, all elongate, trilobed, e.speeially leaf 2. X\- P. 99. Fig. 27. Sucker from base of adult tree. Leaves, especially 2, elongate, trilobed. XJ. Figs. 26-27. West Chop, Martha's Vineyard, Mass. P. 99. Fig. 28. Seedling, cotyledons elongate, nepionic leaves, 1 neai'ly ovate, dentate, 2 elongate, trilobed. Jackson, N. H. Xl. P. 99. Fig. 29. End of branch of adult showing, 1 typical leaf of species, and 3 a, b elongate trilobed leaves. West Chop, Martha's Vineyard, Mass. Xh P- 99. Acer oblonc.um. Fig. 30. Species having elongate, entii-e leaves, the veining is similar to that of the Red Maple, Fig. 29. Xj- Province of Hupeh, China. X^. P. 100. Acer carpinifolium. Fig. 31. Species having leaves with slightly .serrate margin, but no lobes. Nikko, Japan. X J. P- 100. Acer crataegifolium. Fig. 32. Species having leaves with slightly developed lobes, compare the two leaves of this figure, with leaves 1, 1, f Fig. 28. Nikko, Japan. X |. P. 100. 146 ROBERT TRACY JACKSON ON Acer taktakkum var. ginnale. Fig. 33. The proximal pair of leaves entire, very slightly dentate, the next [lair with well developed lobes, compare with leaves 2, Fig. 28. Jes.sn, Japan. Xi. Figures 30-33 from .specimens in herbarium of Arnold arboretum. P. 101. Figs. 30-33 drawn by Mr. J. 11. Emertou ; others by the author. PLATE 18. Acer platanoides. Fig. 34. Sucker from stump of adult, showing Irilobed leaves. Cultivated. X l- P. 100. Negundo aceroides. Fi". 35. Sucker from ba.se of adult with a simple, trilobed leaf fullnwed by a tritoliolate leaf (as leaves are opposite in this species the mates of the two leaves figured must be considered ab.sejit from accident or repression). Cultivated. XV. P. 102. Fig. 36. Typical leaf of adult. Cidtivated. Reduced. P. 102. Gtmnocladus disicus. Fio-. 37. Typical but small leaf of adult, twice pinnate distally, once pinnate proximally. Much reduced. P. 102 and 140. Fig. 38. Sucker from root of same tree as Fig. 37, leaf once pinnate. Cultivated. Xj. P. 102. Gleditschia triacantuos. Fig. 30. Seedling shoning-the cotyledons which are oval, auricleil at the base embracing the stem, the nepionic leaves are alternate, panpinnate, with many leaflets. Cultivated. Xl. P. 102. Fatsia japonica. Fig. 40. Small but typical leaf of adult, palmately deeply cleft. Cultivated. X'(. P. 104. Fie. 41. Seedling showing obovate cotyledons, and nepionic leaves 1 ovate, 2 subcordate, 3 trilobed, all finely serrate. Cultivated. X l- P. 104. Fig. 42. Sucker from the base of an adult raised from .seed, leaf 1 trilobed, 2 subcordate, both finely serrate. Compare Fig. 41. Cultivated. XI. P. 104. Hedera helix. Fig. 43. Seedling showing cotyledons ovate, nepionic leaves alternate, 1, subcordate with a slight lobe on one side ; 2, subcordate, nearly triangular ; 3, tivedobed ; 4 (younger), weakly trilobed ; .5, nearly triangular ; compare with leaf 2. Flor- ence, Italy. Xl. P. 104. Fi" 44. Branch of adult vine, leaf 1, five-lobed ; 5 (younger), weakly five-lobed ; 6-8, broadly trilobed ; compare with Fig. 43. Cultivated. Xj. P. 105. FrAXINUS AMERICANA. Fig. 45. Seedling showing cotyledons elongate, distally blunt, and lU'pionic leaves, simple, opposite, elongate-ovate, petiolate. Xi P. 105. Fin-. 4(5. Tip of older seedling. First nepionic leaves (not shown) all simple, next leaves trifoliolate, lateral leaflets sessile, terminal leaflet petiolulate. Xi. P. 106. Fi". 47. Sucker from ro(.)t near the base of an adult tree. First leaves alternate, simple, petiolate, oval, distally acumi- nate, terminal leaves opposite, trifoliolate, lateral leaflets sessile, terminal leaflet petiolulate, all leaves except 1 serrate. Compare Figs. 45-46. Xi- Figs. 45-47, Milton, Mass. P. 106. LOCALIZED STAGES IN DEVELOPMENT. " I47 Fig. 48. Typical leaf of adult, lateral and terminal leaflet.s petiolulate. Compare with Figs. 40, 47. Emerson (70), reproduced by permission. Reduced. P. 106. Figs. 34-48 drawn by the author. PLATE 19. Sassafras sassafras. Fig. 49. Seedling .showing fruit adherent, uepionic leaves alternate, elongate-oval. Leaf 0 has .sliglit marginal depres- sions. Sliady Hill nurseries, Bedford, Mass. xl. P. 107. Fig. 50. Tip of an older seedling, all proximal leaves (not sliown) oval, terminal leaves two- or three-lobed. West Chop, Martha's Vineyard, Mass. X .i. P. 108. Fig. 51. Small but entire branchlet of adult, first ionr leaves entire, oval. Succeeding leaves tluve lolieil, compare Figs. 49-50. West Chop, Martha's Vineyard, Mas.s. Xi. P. 108. MVRICA CERIFERA. Fig. 52. Seedling .showing broad, spatliulate, di.stally emavginate cotyledons. Tlie first nepionic leaves are .spatliulate tridentate, witliout petioles, in later nepionic leaves more dentations and petioles develop progressively. Xi- P. 113. Fig. 52a. Enlargement of cotyledons and first nepionic leaves. X 3. Arnold arboretum. P. 113. Fig. 53. Typical leaves of adidt, oval, petiolate, distally dentate. Compare with young leaves of Fig. 52. Cohasset, Mass. Xl. P. 113. Platanus orientalis. Fig. 54. Seedling showing strap-shaped cotyledons, and nepionic leaves which are elongate, cuneate, distally tridentate. In these leaves the blade extends to the base of the leaf, no petiole having developed. (Lubbock, '92.) Reproduced by tlie courtesy of Messrs. D. Appleton & Co. Xl. P. 109. Platanus occidentalis. Fig. 55. Sucker from the base of an adult tree, leaves elongate, cuneate, distally dentate, blade extending nearly to tlie base of the petiole. Compare with Fig. 54. Xl- P. 109. Fig. 50. Another sucker from the base of an adult tree. Leaves elongate, trifid to trilobed distally, blades extending far down toward base of petiole. xJ. P. 109. ' Fig. 57. Typical leaf of adidt, five-lobed, marginally dentate, blade extends only a short distance down the petiole forming an obtuse angle proximally. Xj. P. HO. Fig. 58. Vigorous leaf from the upper part of a sucker (several feet from the ground), five-Inlicd, highly dentate marginally with a prominent basal lobe which stands out tree from the petiole. Fig 58a, so tliat the leaf is pertoliolate. XA. P. 109. Fig. 58b. Stipules forming an encircling ruffle about the base of the petiole of leaf Fig. 58. X'- Figs. 55-58 all frcjni one tree. Milton, Mass. P. 109. Figs. 52-53 drawn by Mr. J. H. Emerton ; others by the autlior. PLATE 20. HiconiA ovata. Fig. 59. Seedling .showing nut resting on the gi'ound (dotted line), nepionic leaves 1-3 simple, ovate. Leaf 4 abnormal with one lateral leaflet. Leaves 5-0 trifoliolate. X'.- P. 110. 148 ' ROBERT TRACY JACKSOX ON Fig. 60. Sucker from the base of an adult tree. Leave.s 4-5 simple, ovate ; leaves 6-7 abnormal, with one lateral leaflet ; leaves 9-10 trifoliolate. Xi. P. 110. Fig. 61. Tip of branch of an adult, shovving 1, typical lr;if "f the species; 2, trifoliolate leaf occurring typically at the end of branches. Compare with Figs. 59-60. Xi. Figs. 5y-iral manner, as in the younger upright axis, but come off alter- nately from the sides of the young rhizome. As a result, the foliar lacunae occur on opposite sides of the fibrovascular tube and frequently overlap, so that in certain planes of cross-section, there is presented the appearance of independent dorsal and ventral steles. In the meantime a rod of bi'own sclerenchyma, oval in ti'ansverse section, has made its appearance in the midst of the fundamental tissue occupying the center of the stelar tulje. At a point about two or three centimeters from the region of bifurcation of the young rhizome, the dorsal wall of the stelar tube becomes involuted, and gives off a bundle into its cavity, which is quickly siu'rounded Ijy a tubular sclerenchymatous sheath, formed by the bending round it from l)elow, of the rod of brown sclerenchymatous tissue already mentioned. The ensheathed single central vascular strand gives off branches to the leaves and is from time to time reinforced by additions from above. Subsequently it divides dorsiventrally into two, in a manner which need not be described here, and the original vascular tube having in the meantime become transformed into a complex tuliular network of strands, the state of affaii's which is characteristic of the adult is reached. As the result of the observations described in the foregoing paragraphs, the writer has reached the conclusion that the outer bundles are not cortical, as is stated by Van Tieghem, and that the two large inner ones, which he appears to have confused with the dorsal and ventral primary strands of the yovniger horizontal rhizome, are in reality medul- lary strands. That the outer series is priiniti\'e is indicated, moreover, by the fact that Ijoth the root-traces and the leaf-traces are attached to it. The above account gives little support to Van Tieghem' s theory of polystely, since the young vascular axis is first and always a tube and does not become successively divided into two, four, eight, etc., strands, as he describes. It might be supposed that the state of affairs in Fteris aquUina is possibly abnormal, but the writer is in the position to assert, from the examination of the development of a large number of vascular cryptogams, belonging to the most different groups, that the course of development in Pfer'ts nquiii/ia is quite typical, and that there is no evidence in an}' case which has come under his notice 160 EDWARD C. JEFFREY ON of 11r' repeated dichotomy of the primitive strand wliich has l)een indicated by Van Tieghem. The writer's results in the example described moreover agree with those of Leclerc du Sablon (Ann. sci. nat. hot., ser. 7, tom. 11) for his figures and descriptions of the youiKjer stages of the stem of Pti'i-'is aqin/iufi are ((uite in harmony with the state- ments above. He has made the curious mistake, however, of regarding the mature rhizome of this species, as derived from an adventitious bud on the young plant, although Hofmeister's (Higher cryptogams, Ray soc, p. 213) account is correct in this respect. The writer's study of the development of the stem in a wide range of North Ameri- can and exotic Pteridophyta has led to the result that, in the vascular axes of stems, there are just two primitive types of stelar structure, viz., the single concentric strand, and the tuljular concentric strand, and moreover that all the varied complexities of the mature stem may readily be derived from these by the study of development in the individual cases. Tliere can be little doubt that the simple concentric strand is the more primitive type, and that the tubular concentric strand was subsequently derived from it. The writer is inclined to attribute the origin of the tubular type to the action of mechanical causes, but it would be out of place to discuss this subject at the present time. The two primitive types of stele described above may, however, be appropriately designated, pi'O- tostelic and siphonostelic respectively. In the protostelic axes of the Hymenoiihyllaceae we generally find the concentric type of stele, but in the genus Hemiphlebium (Prantl, Die Hymenophyllaceen, Plate 4, figs. Gl, 02) the bast disappears on the lower side of the stele, which thus becomes collateral. The Ophioglossaceae afford examples of this unilateral degeneration of the bast in siphonostelic stems. From a study of the development of the young stem of species of Ophioglossum and Botrychium the writer is able to state that there occurs here the same stelar tube as in the young stem of Pferis aquU'ma. The two types differ only in the absence of internal bast in the former. The researches of Poirault (Recherches anat. sur les crypt, vasculaires, Ann. sci. nat., hot., ser., 7, tom. 8), and Van Tieghem (Journ. de hot., 1890) have demonstrated the presence of an internal endodermis in the young stem of various Ophioglossaceae. It is interesting also to note tliat the leaf-traces of Bofrt/chium virginianium are concentric, and like those of the cycads retain in all probability a primitive type of organization, which has disappeared in the bundles of the stem. Our examples have up to the present been drawn from the Filicales. The primary vascular axes of livhig Lycopodiales rarely present the phenomena of siphonostely. A o-ood example, however, is to be found in Selaginella laevifjatu Blk., var. lynUii Spr. The stelar tube in this case resembles that of Fteris aquilina and has likewise a pair of medul- THE GENUS EQTJISETUM 161 lary strands. In a photograph 1 (PI. 27, fig. 1), the stehir tube appears with a lacuna in * its side, where the vascuhir strand of a branch has been given off, this gap is the ramular lacuna. The leaves originate from the stelar tube, however, without causing any break in its continuity. Photograph 2 (PL 27, fig. 2) shows the restoration of the integrity of the tube below the point of origin of a subsequent branch. In photograph 3 (PI. 27, fig. 3), we have a copy of Williamson's figure (Phil, trans, roy. soc, 1881, PI. 52, fig. 9) of the tubular stele of Lepidodendron harcourtii. The vascular tissues in this form are likewise arranged in a tul)ular fashion. The leaf- traces are small and cause, according to his description, no interruptions in tlie walls of the tul)e. Where a I)ranch is given off on the contrary, as in the figure, there occurs a ramular lacuna. Both Renault (Cours do bot. foss., tom. 2, p. 71) and Gibson (Annals of bot., vol. 8, p. 192) have been struck by this resemblance between Selaginella laevi- gata var. lyallii and Lepidodendron harcourtii (other species of Lepidodendraceae had similar peculiarities, e. (/., Halonia, Ulodendron, and species of Sigillaria, etc.), and Bertrand {PhyUoglossum druvimondii, Arch. Ijot. Nord France, 1885, p. 71) considers his Centradesmideae (in part) as belonging to the same type. In comparing these instances with the examples taken from the Filicales, it is to be observed, that while both cases represent siphonostely, there is this marked diff"erence between them: in the filicineous stems the siphonostely is characterized by the occur- rence of foliar lacunae, while in the lycopodineous axes it is related to I'amular lacunae. Without going further into the matter at the present time, the hypothesis i.s presented that siphonostely has a mechanical significance, and that in the case of the Filicales, the siplionostelic modification of the vaso-skeletal tissues arose in connection with the support of large leaves. Among the Lycopodiales it made its appearance on the contrary, in relation to the support of secondary axes. We may consequently call the siphonostely of the Filicales phyllosiphonic, and that of the Lycopodiales cladosiphonic. At this stage we come naturally to the discussion of the bearing of these morphologi- cal conceptions, assuming that they are well founded, on the phylogenetic position of the Equisetaceae. In this connection it is necessary to examine with some care liotli the structure and development of the genus Equisetum, and since certain of its features can only be understood in the light of a knowledge of its ancestors, it will likewise be neces- sary to refer as briefly as may be to the organization of the Calamites and Sphenophyl- lales. It will conduce to clearness and b'^evity of exposition to begin with the extinct groups and subsequently to describe their living representntives. 162 EDWARD C. JEFFREY OX Calamites. The Calamites first make their appearance in the Silurian deposits (Stur, Sitzungs- berichte akad. d. wissensch. Wien, bd. 83, p. 400) but their petrified relics and casts are so rare in these earlier strata, that the upper Devonian and lower Carboniferous beds give us the first definite idea concerning the organization of the more primitive representa- tives of the group. One of the oldest Calamites of -which we possess any detailed infor- mation is the genus Archaeocalamites Stur. (Stur, Abh. d. k. k. geol. reichsanstalt, Wien, bd. 8. Heft 1. Culm-flora d. mlihrischen-schlesischen dachschiefers. Heft 2 Culm-flora d. ostrauer u. waldenburger schichten.) In this form there is present the jointed stem which is characteristic of the modern Equiseta. The ridges and chiinnels of the stem, however, differed from those of Equisetuin in not alternating at the nodes. The leaves which originated in the nodal region and were not united into sheaths, but were quite free from one another and dichotomously divided. The roots also ajipeared in relation to the nodes and were often forked like the leaves. Branches were frequently present in the nodal region, but they do not seem to have been very numerous. Of the ]iature of the strobili of this genus, very little is known, as they have been very imperfectly preserved. Tlie vascular frame-work, with which we are fairly well acquainted, as the result of the investigations of Goppert, Renault, and Solms-Laubach, had the same general features as that of Equisetum, differing only in its continuous strands, and its secondary growth in thickness by means of a typical cauiljiuni. The Calamites proper, differed from Archaeocalamites in their generally undivided leaves, and the continually more pronounced (in more recent strata) alternation of their vascular strands at the nodes. They possessed, like the older type, a cylinder of second- ary wood. Their strobili are comparatively well known and vary greatly in structural details, presenting throughout a marked contrast to Equiseta, in the probable division of their sporophylls into dorsal sterile, and ventral generally peltate sporangia-bearing segments (Scott, Cheirostrobus, Phil, trans, roy. soc, 1897, B). According to William- son and Scott (Phil, trans, ro}'. soc, 1894, B. p. 864, 868, 890) their branches originated, in contrast to those of Equisetum, ;il)0ve tlie nodes. From Weiss (Steinkohlen-Cala- marien, Heft 2, p. 34), we learn that the roots of the Calamites were attached either at the nodes or slightly to one side (he does not say, however, which side) . Most frequently calamitean remains occur as casts of the medullary cavities. These casts represent accurately the inner configuration of the fibrovascular cylinder and are consequently constricted at jjoints corresponding to the nodal woody rings and channelled along the course of the primitive bundles. As the primary rays between the primitive bundles w^ere bridged over more or less rapidly by the secondary wood, they appear THE GENUS EQITISETUM. 163 merely as broad, roiiiidi'd, longitudinal elevations on the cast between the depressions above mentioned. At one side of the nodal circular depressions and on the ends of the rounded ridges corresponding to the primary medullary rays, there occur frequently knob-like projections. Sometimes less marked tubercles appear in a similar position ou the other side of the node. Brongniart (Hist, des vegetaux fossiles) who did not realize that he was dealing with casts, explained the larger nodules as representing rudimentary branches and roots (p. 109), and curiously enough considered them to occur on the upper side of the node, although he was clearly aware that in Efpiisetmn jiuviatile, which he used as the biisis of , his comparison, the roots and blanches come off below the articulations, and alternately with the leaves (p. 103). The other and often absent zone of tubercles he explained as undevelo])ed leaves (Brongniart, o/). clt.) . His ideas concerning the rudimentary' char- acter of the organs represented by the tubercles probably originated from the observation that in specimens, which are otherwise apparently well preserved, the nodules in question are frequently entirely absent. Subsequent investigations, which need not be detailed here, established the fact that in branching rhizomes, the orientation of which can be inferred, the more conspicuous nodules of the cast occur below the node and at the upper end of the loucjitudinal rida-es. It has not been so easy to settle the nature of the anatomical features of the calami- tean woody cylinder, which gave rise to the ring of more prominent tubercles. In photo- graph 4 (PI. 27, fig. 4), which is copied from Williamson (Phil, trans, roy. soc, 1.S71, pi. 26, fig. 22), we see a tangential section of the primary bundles of a Calamite, which is so close to the medulla that the carinal canals of the protoxylem of the bundles are laid open. It is to be noticed, that the course'of the bundles is the same as in E([uisetum, except, that on the left of the figure no alternation takes place at the node. Above the node are represented the vascular strands belonging to branches, or as has been stated more recently (Williamson and Scott, Phil, trans, roy. soc, 1804, B., p. 876) to leaves. It is to be observed that these writers assume for the Calamites a different relation of the branches to the nodes, from that obtaining in Equisetum, i. e., that they originated above the node and not from the node, as in the latter (Williamson and Scott, op. cit., p. 890). In the medullary rays, below the nodal wood, the parenchyma is seen in spots I to be somewhat disintegrated. In photograph 5 (PL 27, fig. 5) which is a copy of a figure (Williamson, Phil, trans, roy. soc, 1878, plate 20, fig. 23) representing a more external longitudinal section passing through the secondary wood, may be seen the branch-traces m (or leaf-traces as they were later called) no longer running free in the upper medullary rays, but arched over more or less by strands of secondary wood. In the lower rays disintegration has gone so far that actual cavities, I, have made their 164 EDWARD C. JEFFREY ON appearance. Sucli cavities were considered to l)e definite canals by Williamson (o/;. cit., 1871, 1878), and he accordingly called them infranodal canals. He expressed the opinion that the larger series of tubercles described aJjove, as occurring on the pith-casts of Cala- mites ai"e moulds of these canals in stone. Subsequently in collaboration with Scott (Phil, trans, roy. soc, 1894, B., plate 78, fig. 11) he published a figure, which is reproduced in our photograph G (PI. 27, fig. 6), which may be considered as representing a tangential plane of section, somewhere between those of the two former figures, reproduced in our photographs 4 and 5 (Pi. 27, fig. 4, 5). In this figure the traces making their exit in the superior medullary rays, are no longer considered as belonging to branches, but on the contrary to leaves (Phil, trans, roy. soc, 1894, B., p. 876). Stur (op. cit.) from the study of the casts of various Calamites and of the stem of their modern representatives, the Equiseta has reached certain conclusions whicli it will not be profitable to consider fully. He states, however, that Williamson's figure, repro- duced in our photograph 4 (PI. 27, fig. 4), is inverted, and that the areas of disintegrated parenchyma, which by the inversion of the figure in question, he places in the upper medullary rays are due to the disappearance of leaf-traces. He enforces this contention by objecting that Williamson's figures make the branches arise above the node and not below it, as he thinks should be the case, from the analogy of Equisetum. He comes to the conclusion that the infranodal canals of Williamson are consequently supranodal indications of leaf-traces, and that the large nodules of calamitean casts, already referred to, are as a result above the node, which hardily follows from his course of argument. It is, moreover, in many cases certain that the larger nodules are below the nodal constric- tions of the casts, for reasons which have been already indicated. Weiss (Steinkohlen-Calamarien, Heft 2) has more recently discussed the vexed ques- tion of the tubercles, and after calling attention to Stur's inversion of the casts, expresses his opinion that the disputed nodules, probably represent the points of attachment of either roots or leaves. He realizes that their occurrence below the nodes, and in alterna- tion with the' vascular strands, makes it difficult to regard them as related to the leaves. This would seem to lead to the alternative, that they are the indications of the attach- ments of roots. He does not draw this inference, however, although he records the fact that the nodules are absent entirely, or very imperfectly represented, on parts of Cala- mites which are undoubtedly aerial (oj). cit., \'>.2i) . He leaves the question of their interpretation open, having previously stated that he does not i-egard the nodules as casts of Williamson's infranodal canals. Solms-Laubach (Fossil botany, Eng. ed., p. 301-315) discusses at length the organiza- tion of the calamitean stem, and the nature of calamitean casts. As a result of the con- sideration of all the evidence, he comes to the conclusion, that the more conspicuous THE GENUS EQUISETUM. 165 series of nodules on the medullary casts of the Calamites are really infranodal, and agrees with Williamson in regarding them, as the result of the regular disappear- ance of tissues in the lower medullary rays, but considers tliat the disintegration is due rather to unec^ual maceration, than to the presence of any special organs or canals. The opinion of Graf zu Solms in such matters rightly carried great weight, and after its expression practically in favor of Williamson's view, the latter thought it no longer neces- sary to defend his hypothesis (Williamson and Scott, Phil, trans, roy. soc, 1894, B., p. 888) . Seward in his recent admirable treatise on fossil plants (1898, p. 324) adopts Will- iamson's explanation as quite proved, and does not even discuss the other views. Renault (Etudes des gites miueraux de la France, fasc. 4, atlas) has recentlj- pulj- lished figures of tangential sections through the inner part of the secondary wood of Calamites, in which are represented the usual more or less constantly alternating vascular strands. Above the nodal anastomoses, and at the bottom of the upper medullary rays, are indicated radiating traces, o, which are stated in the description of the plates to be "aquiferous organs." Below them are I'epresented smaller traces,/, embedded in the vas- cular strands, which are regarded by this author as leaf-traces. His " aquiferous organs " are undoubtedly the homologues of the "leaf-traces" of our photograph 6 (PI. 27, fig. 6) copied from the monograph of Williamson and Scott. In the full descriptive text, which appeared three years after his plates Renault (Etudes des gites mineraux de la France, fasc. 4, p. 93) informs us that his figures, one of which is copied in our photograph 1 (PI. 28, fig. 1) should be inverted, and that his " aquiferous organs" are really " organes rhiziferes " which he regards as the equivalents of Williamson's infranodal canals. He states also that he has found roots in connection with the organs in question. These observations open up again the whole subject of the infranodal canals, and it is to be regretted that Renault has not given us reasons for the subsequent inversion of his figures. As will be shown in the sequel, a consideration of the structiu'e of Equisetum gives us criteria for explaining all the foregoing conflicting accounts and apparently for set- tling this much-disputed question. Sphenophyllales. There remains to be said something concerning the organization and structure of the Sphenophyllales. Like the Calamites and Equisetaceae, they had a regularly jointed and furrowed stem. The ridges of the stem did not alternate. The leaves somcwliat resembled those of Archaeocalamites in being dichotomously divided, and were arranged in superposed whorls. The branches, according to the account of Renault (o/>. cit., 166 EDWARD C. JEFFREY ON p. 170), originated at the nodes, and he tells us that they came off from the stem between the leaves, and consequently like those of Calamites and Equisetaceae were not axillary. The fructifications of the Sphenophyllales were cones of superposed verticils of sporophylls. These consisted of a dorsal sterile segment, and one or more ventral spo- rangiferous segments, bearing as a rule on their upper surface a single sporangium which hung inwards towards the axis of the cone. Solms-Laubach (Jahrbuch geol. reichs- anstalt, 18!)5, vol. 45, p. 239) has recently described an interesting strobilus, Bowmani- tes romeri, belonging to tliis group, in which the sporangiophores are transversally peltate like those of the cycad Encephalartos. Tiie most interesting cone of this class, however, is that of which Scott (Cheiro- strobus, Phil, trans, roy. soc, 18U7, B.) has still more recently given an account. The sporophylls of Cheirostrobus are arranged in superposed verticils of twelve members. Each sporophyll consists of a dorsal and a ventral tripartite segment. The former is sterile, and the latter has each of its three divisions developed into a typical peltate sporangiophore bearing four sporangia. This author calls attention to the marked resemblance of his cone to the calamitean Palaeostachya and Calamostachys. The internal features of structure in the stem of the Sphenophyllales were remark- able. There was a protostelic triarch, hexarch, or dodecarch (Cheirostrobus) central cylinder. The groups of protoxylem were generally distinguished by the presence of carinal lacunae as in Equisetum. The central cylinder was further characterized bv the presence of a peculiar secondary wood. Other points of anatomy need not be considered here. Observations on the Genus Equisetum. The development of the prothallus of Equisetum has been very elaborately studied by Buchtien (Eiitwick. prothall. von Equisetum), and the writer's investigations accord in their results with his, so far as they have gone. The gametopliyto consists of a median vertically growing fleshy axis terminated by meristematic tissue, in which it is not pos- sible to make out a definite apical cell. From this terminal, actively dividing tissue lateral lobes are produced, to which the sexual organs have a definite relation. The main axis seldom forks in E. Ihaosum and U. arvense, but frequently does so in the large prothalli of £!. hiemale chiefly studied by the writer, and there may be as many as four or five secondary axes in the latter species. The antheridia are formed at the tips of the lobes in a manner which has been often described and need not be referred to here. The antherozoids likewise do not THE GENUS EQUISETUM. 167 require special description, as they have heen fully investigated iu recent years by Buch- tien and Belajeft". The archegonia, however, require more attention. They originate, as has been observed by other writers, frequently, but not invariably, near the base of a prothallial lobe. A superficial cell becomes more rich in protoplasm than its neighbors, and under- goes transverse division into nearly equal parts, in this respect presenting a contrast to the mother-cell of the archegoniam of the isosporous Filicales, where the first division results in the formation of a shallow outer cell and a much deeper inner one, PI. 26, fig. 1. The young archegoniiim in the two-celled stage resembles closely that of Lyco2wdmm davatum (Bruchmann, U. d. prothal. u: d. keimpflanzen mehrer. europ. Lycopod., PI. 3, fig. 12; I am indebted to Dr. (J. L. Goodale for calling my attention to this recent work) of the same age. Treub (Annales du jardin hot. de Buitenzorg, turn. 4, 5) unfortunately does not figure such early phases in the case of L. cernuuiii. and L. jMec/maria. In PI. 20, fig. 2, is represented a later stage, in which the inner cell has become equally divided by a second transverse wall. The outer cell i\i nearly the same time becomes bisected by a perpendicular wall. Frequently the outer cell at this time is still undivided, and in such cases the perpendicular row resembles the three cells of the young archegonium of the isosporous Filicales, but the significance of the cells in the two ca?es is very different, in the former they are cervical cell, cervical canal-cell and central cell; ill the latter, cervical cell, central cell, and basal cell. It was probal)ly an archegouimn at this stage of development somewhat obliquely cut and consequently showing only part of the central cell, which led Campbell (Delt. of mosses and ferns, p. 430, fig. 223b) to make the statement that a basal cell sometimes occurs in the Equisetaceae. .lanczewski (Bot. zeit., 1872, p. 420), Sadebeck (Schenck, Ilandbuch d. Ijot., bd. 1, p. 100), and Buchtien [o^). cit., p. 20), all agree in stating that there is no basal cell in tlie archegonium of the genus Eqiiisetum, and with this assertion my own observations on a large number of examples of J'J. JiiemaJe, E. Ihiiosrua, and E. (irpenae are ([uite in accoi'd. PI. 26, fig. 3, represents a young archegonium of E. hlemde, in which the central cell has already given off the ventral canal-cell, and as a result has become the egg-cell. The neck has become further developed and the cervical canal-cell is beginning to [lush its way iqi- wards. In PI. 20, fig. 4 is represented a nearly ripe archegonium. The neck remains short in E. hiemnle. The cervical canal-cell has become longitudinally divided into two, a peculiarity which has only been described elsewhere in Lycopodlnin phlcymdrUi (Treub, Ann. du jardin bot. Buitenzorg, tom. 5, pi. 21, figs. 9 and 10). The ventral canal-cell has already begun to degenerate. Around the egg-cell cells are cut off from the prothallial cells, by walls parallel to its surface, a feature first observed by Hofmeister and confirmed 168 EDWARD C. JEFFREY ON frequentl}' by sub.se(|ueiit writers. The development of the urchegonium in E. Vimosum and E. arve/itie is practically identical with that of E. hiemale, which has been described above, and they have the same peculiar longitudinally divided cervical canal-cell. Pi. 20, fig. 5 represents a nearly ripe archegoniuni of E. (irueniie. In the two last mentioned S2)ecies the neck is very much longer than in ?]. hiemale and consists of three or four tiers of cells. The luiiforin occurrence of lono-itudinal division in the cervical canal-cell of these three species is interesting and probably indicates tliat this feature will be found to be common to the group. Campbell (Mosses and ferns, p. 427), however, figures a trans- verse division for E.telmateia. Sadebeck (Engler u. Prantl, Nat. pflanzenfam., teil 1, abteil 4, p. 2) has recently published a figure of the archegoniuni of E. arvense which does not at all agree with Fig. 5, but as he does not represent in it the divisions of the pro- thalhal cells parallel to the surface of the egg, and the cuneate insertion of the neck of the archegoniuni which have been noticed by practically all other observers, beginning with Hofmeister, his representation must be regarded as somewhat diagrammatic. The first division of the egg is transverse, the basal wall being generally somewhat oblique. The inclination of the basal septum is sometimes towards the apex and some- times towards the base of the prothallus, more frequently, however, towards the former. It has not been possible to absolutely settle the order of the next two divisions, but it is probable that the median wall is formed first. The transverse wall often does not extend at first entirely across the embryo, especially in the hypobasal half. The apical cell is early formed in the epibasal portion, and in the hypobasal half, an apparent apical cell is also differentiated. These features are shown in PI. 20, fig. 0, which is almost identical with Hofmeister's {op. eit., PL 39, fig. 2) illustration of a similar stage. The develop- ment of an apparent apical cell in the lower half of the embryo, and a tacit homologizing of that region with the corresponding region, as regards the substratuna of the leptospor- angiate embryos, with which he was familiar, led him into the error of regarding it as the embryonic primary axis. As its regular segmentations sooii cease, and it is thrust aside by the growth of the upper portion of the embryo, he regarded the primary axis of Equisetum as abortive. Tlie real primary stem-apex in the upper part of the embryo of PI. 1, fig. 0, he regarded as that of a secondary shoot, an error which has been recognized by Sadebeck (Pringsheim's Jahrbiicher, bd. 11, p. 581), and subsequent observers. Sadebeck {oj). cit.) informs us that in the case of E. arvense and E. pahistre, the development of which he has studied, the epibasal cell gives rise immediately to the primitive shoot-axis, from which the first whorl of leaves is derived exactly as are the subsequent ones. This statement I am not aljle to confirm exactly, for in E. hlemaJe, which I have particularly studied, the rudiment of the first root appears very early, next the apical cell, and on the side of it which faces the apex of the prothallus. PI. 20, fig. 7, shows an embryo at this stage, the THE GENITS EQUISETUM. 169 cells of whu'li have heoii outlined with the camera lucida, a is the apical cell and r is the rudiment of the root. It might be thought that another cell, further down on the right of the young embryo, is really the radical rudiment, but that such is not the case may be determined from the next figure, which is a Irawing of an older embryo made with the camera lucida. The upwardly directed arrows in the two last mentioned figures indicate the direction of the neck of the archegoniuin, and those pointing downwards, the position of the embryos in i*elation to the suljstratum, as inferred from the course of the pi-othallial root-hairs. It will Ije seen from these figures, that the root appears veiy earl3' in ?J. hiemale, and in all probability is derived from the epibasal region of the embryo. It pre- sents in the latter feature a close correspondence to the state of att'airs observed by Treub {oj). cit.) and Bruchmann (oj). cif.) in the embryos of Lucopodium ctrimum, L. plileijmar'm^ L. clacatinii, and L. complanatum. The segmentations of the apical cell 1)ecome numer- ous before the first whorl of leaves makes its appearance in embryos of nearly twice the size of that of Fig. 8. It is accordingly not easy to trace the members of the first foliar whorl to the epibasal octants by allowing, as is usually done, one for the ajjical cell, and one for each of the three primary leaves. It would seem to be a more reasonable procedure to compare the embryo of Equisetum rather with those of the Lycopodiales, concerning which we have in recent years so much information, which was entirely lacking when the fashion of comparing all embryos with those of the probably highly specialized leptosporangiate ferns originated. Such a comparison would lead to our deriving both root and shoot from the epibasal half of the embryo, and leaving the whole hypobasal por- tion for the foot. Without, however, attaching too much importance to this comparison, it may be safely stated that the primitive root of E. hleinale originates high up on the side of the embryo and in close relation to the primitive shoot. As the embryo develops, the root gradually descends, and finally as it begins to push its way out, becomes the most inferior organ of the eml^ryo. The young root is directed towards the apex of the game- topliyte and alternates with the two anterior leaves of the first foliar whorl. The first so- called adventitious Ijud originates al>ove the point of origin of the first root, and likewise between the two primary leaf-traces. The secondary axis differs from the primary in not producing the rudiment of the root, till the first foliar whorl is clearly indicated, as a fold round the secondary stem-apex. About the time of the appearance of the first adventi- tious 1)ud, and when three or more whorls of leaves have been formed on the young axis, the shoot breaks through the calyptra, the root having previously in the case of E. hiemale and E. arvense made its way into the soil. In E. Hmosmn the root develops very slowly and does not enter the soil till long after the shoot has made its way out. This is probably the result of its amphil^ious mode of life, as many plants of this hal)it have a poorly developed primary root e. g., Nelumh'mm luteiuii. The writer has not a sufficiently <. 170 EDWARD C. .IEFF1?F.Y ON comjilete series of fiiibr} os of J'J. ((rveiise ami h\ /iiiiosimi to (lescrihe completely tlie ciiilirv- ogeiiy of these sjjecies. Moreover, the exainiiiatioii of the earlier phases of development is rather to he jiassed over in this essay since a good deal of attention will he given to the later stages which have heen almost entirely neglected by ]>revions writers. Tlie first shoot of /i". hiciixiJe, after bursting through the caly[)tra, forms from six to twelve segments, and tlien ceases to grow. Some time previously, however, the first s(j- called adventitious shoot has emerged below tlie point of attachment of the first foliar whorl of the primary axis. This secondary axis is terminated interiorly by a root whidi originates below its 2)rimaiy whorl of leaves or ocliicola. The secondary axis is followed by a tertiary axis wliicii springs from below its lirst sheath and between two leaf-traces. These features are rejjresented in PI. 26, figs. '••, 10. The next figure shows us a some- what oldei' plant, in which a inunber of shoots have been successively formed in the order indicated by their numeration. It is to be observed that each shoot has a corresponding root. In the stouter later shoots the nodal buds, which develop normally as shoots, are no longer confined to the basal nodes, but appear also in relation to the higher articulations, as may be learned from PI. 26, figs. 10, 11. As each new axis originates well down towards the attachment of the root of its predecessor, the later formed shoots are continually moi'e deeply buried in the soil. Fig. 11. In K. Juctiuilc twelve or more erect shoots are i'oi'ined before a horizontal rhizome makes its appearance, from the base of one of the larger and more deeply buried secondary upright axes. It would be interesting to discover if the depth of the pai'ent axis in the soil has anything to do with the formation of these plagiotropic shoots ; the writer, however, has not made any ex})eriments in this direction. The first shoot of E. Jue)imle has foliar sheaths of three niend)ers, the second shoot has frequently similar sheaths, but more often has whorls (jf four united leaves, then follow axes with verticils of four, five, and six membei's. The writer's cultui'es of E. Ihnosum did not produce plants of more than two devel- oped shoots. It is apparently difficult to secure the proper conditions for the continued growth of this species, for, unlike E. hienKt/c, it does not li\e long under greenhouse conditions. Here the first shoot may have leaf-whorls of onl\ two members; in fact, the plants grown from spores obtained from a swamj) aljout fifty miles northeast of Toi-onto, were practically all characterized by this peculiarity. Buchtien (o/j. cit., i). 40) has noticed a similar peculiarity in the case of E. rar'tecjntinn. Sporophytes from spores gathered by the writer from plants on the Ijorder of Ilowanl Lake in High Park, Toronto, had, on the other hand, almost invariably sheaths of three mendjers. A study of the sporogeny showed that in the former case a considerable nund^er of spore-mothers became disintegrated after the tetrad division had taken place. This did not occur in the material from High Park. It is possible that, in the liist instance, too large an amount of spo- THE GEXirs EQUrSETlTM. ]7| rogenous tissue had ^-iven rise to spore-mothers ami too Httle to the fonnatioii of ta[)etal cells, and, as a consequence, the resultant spores produced only depauperate plants. A series of observations in this dii-ectiou uiiglit prove interesting in connection with Bower's theory of the origin of tlie sporopliyte. PI. 2G, figs. 12 and 13, sufficiently illustrate the external features of the young sporopliytes of E. /imnsinii, and show that they do not differ essentially from those of U. likmale, except in their greater delicacy, and in the smaller number of segments formed in the first shoot. Turning our attention now to the internal development of E. /ilciiifiic, we {\\u\ that in the first axis of the young sporopliyte there is a gradual ti'ansition from the typical arrangement ol the tissues in the root, to that obtaining in the base of the youni;- stem. The central cylinder of the first shoot makes its appearance as an unbrokeu tube of reticulated tracheides. There are no typical protoxylem elements, although the internal tracheides are formed first. The jirimitive vascular axis, in fact, starts out with a similar organization to that which is found subsequently to recur at the nodes. The center of the vascular tube is occupied by })arenchyma, which may be considered in the light of what is to follow, as belonging to the pericycle. Outside the ring of reticulated vessels occurs a zone of phloem, terminated by a typical eiidodernns. with the usual radial ligiiilied hands. The rndhnent of the second shoot causes an interrui)tion in the continuity of the vas- cidar cyliniler of the primary axis aliove its point of origin which disappears again, at about the level of exit of the leaf-traces from the central cylinder. The latter do not cause any gaps in the vascular ring as they pass off, and it is only at a measuralile dis- tance above their points of origin, that the so-called foliar lacunae make their appearance. The first slioot-bud originates between two leaf-traces as do all the subsequent ones. The foliar lacunae described above, if they may so be called, divide the fibrovascular tulje into three distinct strands which alternate with the leaves. These three strands differ from the woody ring below in having typical protoxjlem elements, which lie in more or less characteristic carinal lacunae. They are surrounded by a common external endodermis. At a point two or three millimeters above the e.xit of the leaf-traces of the primar\' whorl, a cell makes its appearance in the midst of the internodal bundles, which is cliaracteriz(!d by having endodernial markings on its walls; still higher up this gives j^lace to a radiating group of cells, which have endodernial dots about the middle of their radial walls. Just above the exit of the leaf-traces of the ne.xt whorl, that is at the base of the next inter- node, the internal endodernial elements disajjpear. They again become evident at a short distance above this point, only to disappear again above the exit of the leaf-traces of the next intei'node. These variations recur in all the segments of the first shoot and need not be further descrilted. In the higher internodes, however, the internal endodermis shows a tendency to unite with the outer one, just below the continuous rings of reticulate vascu- 172 EDWARD C. JEFHtEY ON lar tissue which mark the nodes. It is impossible, however, even in the unbroken series of thin sections, which the writer has studied, witli the aid of phloroglucin and hydrochloric acid, to be sure that such a union actually takes place, as the indications consist only of somewhat irregular endodermal streaks radiating out from the internal endodermis, at the points descri})ed above. From the state of affairs in the adult stem (Pfitzer, Pringsheim's Jahrbiicher, bd. 6; Van Tieghem, Journal de botanique, 1890, p. 365 et seq) , it might be expected that we should find similar indications just above the nodes, but they do not occur. The first node of the second shoot has likewise a pith of pericyclic origin. Here again the internal endodermis makes its appearance only above the primary node. The internal endodermis of the second shoot, however, is continuous throughout the secondary axis and does not disappear at the nodes. It clearly unites moreover with the outer endodermis below the nodal vascular rings. In subsequent shoots the internal endodermis is likewise continuous and finally in shoots of five or more bundles it is foiuid also in the primarj' node and is continuous with the internal endodermis of the parent axis. It is in shoots of five bundles that the internal endodermis first unites with the external, above as well as below the nodes, as in the adult plant. The primary axis does not develop nodal buds other than the basal one, except in some of its higher nodes, and these seldom under ordinary conditions give rise to branches. The second, third, and subsequent shoots have one or more dormant nodal buds at all their nodes. Quite frequently there is an increase in the number of vascular strands in passing from a lower internode to a higher one. In one example, where four strands were present in the first internode, five were found in the second and six in the third, after which the number remained constant. This feature is interesting, as repeating on a small scale a phenomenon which was of common occurrence among the Calamites. Equisetum Ihiioswn is very similar to E. hiemale in the particulars of its internal development. The only differences which need to be noticed are those which have reference to the distribution of the endodermis. In the first shoot of tliis species, whether bifascicular or trifascicular, there are no indications whatever of an internal endodermis, although as may be seen from photograph 2 (PI. 28, fig. 2) the outer endodermal sheath is well developed. The second shoot of E. Ibnosum in my specimens was too immature to show the endodermal marking. The arrangement of the endodermis in the young stems of these two species of Equisetum does not appear to offer very much support to Van Tieghem's (Journ. de botanique, 1890, p. 370) hypothesis of astely, for in accordance with his concep- tion of the origin of astely, the primitive type had above the first whorl of leaves, bundles indi\idually surrounded by endodermal zones, and these individual zones THE GENUS EQUISETUM. 173 becoming subsequently fused gave rise to a continuous outer and a continuous inner endodermis. It is not unreasonable to expect to find some evidence of this in the young stem. If anything may be argued from these embryological results, the primi- tive condition would j-eem to have been one in which there was both an -outer and an inner endodermis. This subject, however, will be more satisfactorily discussed at a subsequent stage. Having examined the external and internal development of the young sporophyte of Equiseta we may now turn our attention to certain features of the adult, wliich are either in themselves interesting, or which are of importance in coming to any conclu- sions concerning the affinities of the Equisetaceae. Photograph 3 (PI. 28, fig. 3) represents a transverse section through the nodal region of the subteri'anean stem of E. hiemale. On the outside of the stem and on the carinal ridges are to be seen certain projecting organs, a, of a parenchymatous nature. These are situated opposite the points where the. leaf-traces leave the central cjdinder to pursue their upward course in the foliar sheaths. They were noticed by Brongniart (o/>. cit.) in £J. litorale, but apparently have not been elucidated since. At h in the same photo- graph may be seen the origin of a root-trace. At c there is present a shoot-bud. This has several roots attached to its lower end which do not appear in the plane of section. Photograph "4 (PI. 28, fig. 4) represents more highly magnified one of the organs referred to above. The sclerenchymatous cortex of the rhizome is here interrupted by a strand of parenchymatous tissue which extends from the leaf-trace outwards. These organs may be conveniently called nodal organs. Their constituent parenchymatous tissue is of a loose and spongy nature, and their organization is quite similar to that of the lenticels which occur on the roots of the higher plants, and we probably shall not go very far astray in considering that these peculiar nodal organs of certain Equiseta have the func- tion of permitting an interchange of gases through the otherwise impervious integument of the rhizome. They make their appearance on the subterranean parts of (juite young plants of E. hiemale as well as in the adult. Photograph 5 (PL 28, fig. 5) shows an entire thin transverse section through the nodal region of E. silvaticum. At a are the nodal organs similar to those of E. hiemale. The origin of root-hairs from the epidermis of the rhizome may also be clearly made out. The outer zone of the cortex is parenchymatous, and internal to it occurs a ring of brown sclerenchyma, the continuity of which is broken by the spongy parenchyma of the nodal organs or by root-traces, h. Inside the sclerenchymatous zone occurs a third, which is of a parenchymatous nature and adjoins the bast of the fibrovascular bundles. The central cylinder is seen to give off six processes, five of which are root-bases and one a dormant branch, c. Alternating with these and much smaller are the leaf-traces, d, subtending 174 EDWARD C. JEFFREY ON internally the nodal organs, a, where these are present. The central cylinder in the nodal region, as has been often described, forms a continuous ring in which the vascular tissue, instead of being scanty and separated into individual bundles, each characterized by an internal lacunar protoxj-lem, as is the case in tlie internodes, is massive and entirely devoid of typical protoxylem elements. At the lower side of the photograph the leaf-traces have quite cleared the central cylinder, and it is to be noticed as a feature of importance, wliicli will be subsequently referred to more at length, that the nodal vas- cular ring is quite unbroken by their exit. In the upper part of the figure, the medulla is seen to extend outwanls into the root-bases. Photograpli G (PI. 28. fig G) is of a section tlirougli the nodal region of E. arvehse. The nodal organs are absent in this species, but the rhizophoric buds, c, are better devel- oped than in U. Idanale and E. sUoaticum. The fact tliat tiie so-called foliar lacunae do not appear immediately above the leaf-traces, as they should from the analogy of the Filicales, but are separated from them by the nodal wood, may also be inferred from this section, which on the whole closely resembles that of E. silvaticuni. Nodal organs have been found by the writer only in E. hieiaale and E. s'dvaticum, and are absent in E. varie- gatum, E. arcense, and E. limosum. In the next photograpli (1^1. 2'.), fig. 1) is shown part of the section through the node of E. limosum. In this species all the iiodnl buds develop as rhizophoric organs except one or two. At c is the single large ramular liud and at b are the rhizophoric organs. The other features of the section need not be described. Turning our attention now to the longitudinal topography of the stem of E(iuisetum we have in photograph 2 (I'l. 20, fig. 2) a tangential section of the nodal region of E. hleinftJe the plane of which is sufficiently deep to lay open the vallecular canals, /, of the lower internode ; a branch, c, is making its way out through one of these. The magnification is sufficient to show that the medulla of the branch is composed of brown sclerenchymatous cells, and that its wood, which is no doubt to be regarded as the nodal wood of the first segment of the branch, is devoid of lacunae, such as occur in the intern* des, and forms a ring, the vessels of which are still immature on the upper side. Above the branch are present four leaf-traces, t, which are about to assume an upward course in the foliar sheath of the main stem. The more profound tangential section of photograph 3 (PI. 29, fig. 3) shows clearly the arrangement of the fibro- vascular bundles at the node. Each bundle from the lower internode widens out at the node and the contig-uous strands become thus united. From this riu"' of nodal wood the buaille-! of the upper internode take their origin in alternation with those of the inferior internode. A branch, e, is starting from the lower border of the nodal wood between two Ibwer vascular strands, and, although the plane of section is so deep THE GENUS EQUISETUM. 175 as to pass through the very base of the branch, there is still a wide brini of noilal wood above the latter. The leaf-traces, as may be learned from the examination of a series of tangential sections, originate on a level with the lower surface of the branch-traces, but as they pass outwards, rapidly i)ass above the latter, as may bo inferred from photograph 2 (PI. 29, fig. 2). A deep tangential section is likewise represented in photograph 4 (PI. 29, fig. 4). The arrangement of the bundles at the sides is the same as in the preceding photograph, but the two central bundles, between which a cluster of thick-walled cells indicates the starting-point of the medulla of a branch, do not alternate but are continued with those of the iuternode above. This [jhenoiuenon is not rare in E. hiemale and is of interest both because it has apparently not been noticed before in Equiseta, and because it exemplifies a mode of fascicular arrangement which was common at the nodes of the Calamites. Ratlial sections show more clearly tlum tangential ones the relations of the branches to the nodal wood, and it is the more necessary to devote some attention to these features, because the opinion prevails tliat the branches of the Calamites in contrast to those of E([uiseta originated above the node. Photograph 5 (PI. 29, fig. -5) shows the topography of a radial section of an aerial stem of E. hteumle, at the point of origin of a branch. At d is the partially sclerified nodal di;i})hragm of the main stem, and below it at n is the nodal wood. From the lower half of the nodal vascular ring comes oft' a branch, c. The diaphragm of the first node of the branch is very deep, and is somewhat sclerified at the ends. Two roots, >•, and a nodal bud, k, are attached to the basal node of the branch. The first leaf-sheath, or ochreola, is present interiorly, but is abortive on the upper axial side. It is manifest that the aerial branch of E. hioiiale arises neither above nor below the node but from the lower region of the nodal wood. Photograph 6 (PI. 20, fig. G) illustrates the topography of the origin of a rhizophoi'ic bud from a node of the rhizome. The same general features olitain as in the last photograph, and it may readily be seen that here, too, the potential secondary axis originates from the lower region of the nodal wood. The lettering is the same as in the preceding photogi'aph. A feature which is worthy of note is that, the first sheath of the bud, the future oclu'eola, is normally developed, as is generally the case in branches derived from the subterranean stem. The next photograph 1 (PI. 30, fig. 1) illustrates the mode of origin of a stout upright branch from a deep horizontal rhizome; as before, d is the diaphragm, n is the nodal wood, and r is a root. Here, too, the branch arises neither above nor below the node l)ut from the nodal wood, and since in this case the base of the secondaiy axis is very broad, it covers the whole of the node. The next photograph 2 (PI. .'Jd, fig. 2) is of a radial section through the nodal 176 EDWARD C. JEFFREY ON region of the rhizome of E. silvaticum. The branch, as in the otlier cases, originates from the lower region of the nodal wood. From all these examples it will be snfticiently obvious that in Equisetuiii the branches arise neither above nor below the nodal wood but from it, and in the case of the smaller branches, from its lower border, and in that of the larger ones, more or less exactly from its central region. In U. liiiiosum at the subterranean nodes, whether of upright or horizontal stems, there are present one or two branch-buds and a number of rhizophorous buds. From the latter as many as six or seven roots grow out into the soil, and the stem-region of the buds more or less completely degenerates. That these root-bearing pedicels are the morphological equivalents of branches is obvious for two reasons : in the first place they possess a typical medulla like the slioot>organs, and are thus distinguished from tlie pitldess roots which are characteristic of the modern Equiseta; secondly, by examining the successive nodes of an upright branch, beginning below the soil and passing upwards, it is possible to distinguish all phases of transition between rhizophoric organs and typical leafy shoots These results are only confirmatory of those of Janczewski (Recherches sur le dev. des bourgeons dans les preles. Mem. soc. nat. sci. Cherbourg, 1876, tom. 20), but it is impor- tant to have independent evidence in these matters as will appear in the sequel. It has already been stated that the leaf-traces originate from the protoxylem of the bundles of the lower internode. Photograph 4 (PI. 30, fig. 4) demonstrates the accuracy of this statement. The leaf-trace is separated rather widely from the surface of the nodal wood, and the endodermis forms a deep bay on the outer side of the node, between it and the leaf-trace, as is represented in PI. 26, fig. 14. Before leaving this part of the subject one interesting feature may be referred to. Photograph 5 (PL .30, fig. 5) I'epresents a section of the nodal diaphragm of JE. hiemcde. It is easy to make out that the cells of the upper portion of the diaphragm are arranged in perpendicular rows, and that the lower members of the rows have become thick-walled, forming the characteristic sclerification of the diaphragm. These features are of con- siderable interest, because peridernial tissue has been recently described as occurring in the diaphragms of Calamites by Williamson and Scott (Phil, trans, roy. soc, 1894, B., p. 889). In the Calamites, however, there was no subsequent sclerification of its cells, the nodal diaphragms of this group being entirely parenchymatous (Williamson, Phil, trans, roy. soc, 1871, p. 505). A similar sclerified periderm has been found by the writer in U. limosum. In U. silvaticum, E. arvense, and E. variegatum, on the other hand no nodal periderm is present. The presence or absence of this feature may be of some use in the difficult task of tracing the relationshijjs of the modern Equiseta. The palaeobotanical writers above referred to compare the periderm of calamitean diaphragms THE GENUS EQUrSETUM. 177 with that abnormally formed in the pith of certain Campanulaceae, etc. It is probably equally justifiable to compare it with that occurring in certain cryptogams. Russow (Vergleich. untersucli., p. 117), for example, has described the existence of periderm in the Marattiaceae and the Ophioglossaceae and the writer (Trans. Giin. inst., 1898, p. 284) has called attention to a similar formation at the bases of fallen leaves in Botrychmm virginianxm. The frequent separation of the stem of equisetoid plants at the nodes, as the result of normal or exceptional conditions, would make such a protection at these points of considerable importance. In this connection it is interesting to notice that the sclerified diaphragms of E. liniosum extend to the outer margin of the vallecnlar canals. They thus surround the vascular bundles, just as is the case with the aljciss-periderm of the leaf-stalks of Hippocastanum, etc. Some of the results described in the foregoing paragraphs seem to the writer not to be without importance in connection with certain disputed points of calamitean anatomy referred to in the Introduction. The two features wliich are most worthy of considera- tion in this connection are the mode of insertion of the branches of the Calamites, and the nature and position of the organs which gave rise to the infei'ior series of nodules on calamitean medullary casts. The BiiAxciiES and Ixfkaxoual Canals of Calamites. Beginning with the first of these, the statement is commonly made by palaeobotani- cal writers that the branches of the Calamites in contrast to those of Equiseta originated above the node. Photograph 6 (PL 30, fig. 6) of the present memoir is a copy of a rare and beautiful specimen of a calamitean stem showing extei'nal features, figured in Weiss's admirable monograph (Steinkohlen-Calamarien, Heft 2, atlas, pi. 16, fig. 6) . Several nodes are present, to which leaves are attached and the scars of a number of fallen branches are to be seen in a singl-e horizontal row. On the lower margin of the branch- scars are smaller scars, which Weiss interprets as belonging to fallen leaves, but when he tells us that these fallen leaves are the appendages of a node which comes immediately below the branches, it is probal)le that the botanical reader, remembering the state of affairs in Equisetum, will hesitate to follow him. If a node is present in this position it is certainly not very obvious and is irregulai-ly placed. Moreover, in similar specimens fig- ured in an earlier monograph (Weiss, Steinkohlen-Calamarien, Heft 1, atlas, pi. 17, figs. 1 and 2), where the leaves were represented only by their scars, in accordance with the conviction that the Ijranches arise above the node, he has considered the smaller scars, related to scars of fallen branches, as dipping down underneath the branches and coming up to the nodal line again in the intervals between the branches. In the example fig- 178 KDWATM) C. .TEFFRRV OX tired licre, since tlio attached leaves are nhvioiisly sitiiateil in sonic cases iniiiuMliutely above the scars of the Inanchcs, lie aliaiidons that position, and assumes the pi*esence of an intercalated node corresponding to tlie crescentic series of smaller scars on the lower margins of the branch-scars. The writer snggests that tlic crescentic rows of scars of the figure, copied in photograpli (i (PI. 30, fig. 0). really belong to the liasal whorls or oclire- olae of the fallen branches and that as a conse<|uence, so far as can be judged fr(jm exter- nal appearances, the branches of Calamites had the same relation to tiie node as those of Equiseta. The ochreolae of the Calamites were not continuous sheaths as in Eqnisetum but were composed of separate leaves. The ochreolae of the Equiseta not infrequently lack fibrovascnlar bundles and are often obsolete on the upper axial side of the branch. The occurrence of similar features in the Calamites is not improbalile and tlie.se would account for tlie absence of leaf-scars on the upper margin of the branch-scars and for the non-retention of the ochreolar leaves, together witli the normal leaves of the nodes of the parent axis in piiotograpli (i (PI. 30, fig. G). But without attaching too much importance to the above explanation, it will l)e well to consider the internal relations of the branches to the nodes, as described in recent works on calamitean anatomy, and, at the same time, to examine the statements as to the nature and disposition of the organs which gave rise to the infranodal tubercles of certain cala- mitean casts. In photograph 6 (PL 27, fig. 6), a copy, tlie original of which has been already indi- cated (Williamson and Scott, Phih trans, roy. soc, 1894, B., pi. 78, fig. 11), is a representa- tion of the nodal arrangement of the vascular strands of a Calamite, as seen in tangential section. It will lie observed that these have, generally speaking, the same relation to each other at the node as is exemplified in our piiotograpli 3 (PI. 29, fig. 3) of E. hiemaJe. In the lower ends of the upper medullary rays are situated certain structures which Williamson and Scott [o/j. eit., p. 87G) consider to be leaf-traces. In photographs 4 and 5 (PI. 27, figs. 4, 5) , which are taken from Williamson's earlier memoirs (Phil, trans. xoy. soc, 1871, pi. 26, fig. 22; iliid, 1878, pi. 20, fig. 23), these are represented as Jieing the vascular strands of branches. The changed inter[)retatioii of the later memoir need not be considered for tlie i)resent, although, as will be indicated suljsequently, it is of some importance. In the later memoir alrea(l\' referred to, Williamson and Scott (Phil, trans, roy. soc, 1894, B., pi. 78, fig. 11) make the statement that tlie leaf-traces in the Calamites originated from the protoxylem of the bundles of the lower internode, and consequently, it may be assumed, below the nodal -wood, since they inform us that the protoxylem came to an end below the node in Calamites, just as it does in the Equisetaceae. Returning now to the statement that the leaf-traces are found in the upper medullaiy rays and con- sequently above the nodal wood, it may be asked how they have got into this supranodal THE GENUS EQUISETUM. 179 position. It can be only in one of two wajs: they must pass up on either the inside or the outside of the nodal wood. But before considering either of these possibilities, one of their figures {op. clt., pi. 78, fig. 7) shows the leaf-trace running directly outwards from the protoxylem of the lower vascular strand and consequently below the node. This is a difficulty in connection with either of the above suggestions. Let us suppose tliat it does not exist, however, and imagine the leaf-trace to pass upwards inside the nodal wood. But this would involve the presence of ringed and spiral woody elements on the inside of the nodal wood, since the leaf-trace consists largely of these elements. They state, however {op. cit., p. 872 and 877), that protoxylem* is absent from the inside of the nodal wood of the Calamites just as it is in Equisetum. These difficulties make us turn to the other alternative, that the leaf-traces pass to their supranodal position on the outside of the nodal wood. Photograph 4 (PI. 27, fig. 4) is a reproduction of a figure from one of Williamson's memoirs (Phil, trans, roy. soc, 1871, pi. 26, fig. 22). The section which it represents is so profoundly tangential that the carinal canals of the protoxylem are laid open. The so-called leaf-traces are nevertheless ali-eady in their supranodal po.sition, and consequently cannot have passed up external to the node. If, in spite of all these dilficulties, the leaf-traces are still maintained to start outwards in the lower. ends of the supranodal medullai'y rays, other difficulties make their appearance. All figures which indicate the internal relations of calamitean branches represent their vascular strands as running in the medullary rays and at the same time aljove the nodal wood. Since, according to William- son's and Scott's statement {op. clt., 18U4, B., pi. 78, fig. 11), the leaf-traces also run in the same rays and in the same relation to the nodes, the branches must originate in the axils of the leaves, which is not only contrary to the arrangement in Equisetum, where the branches originate between the leaf-traces, but also to the statements of Williamson and Scott themselves (oj). clt., p. 8(M, 868, 890) that a similar state of affairs obtained in the Calamites. There i.s, in fact (Williamson, o/j. clt., 1871, pi. 28, fig. 38), a figure of a branch in this anomalous position in one of Williamson's older memoirs, but the joint authors of the hiter memoir already referred to (o^>. cit., 1804, B., p. 800) tell us that this represents an arrangement which Avas exceptional. It is not easy to see, however, why it should not have been present whenever the strands alternated at the node, as they inform us they generally did (o/:*. cit., p. 868, 876, 877), since in such cases the leaf-traces and the branch-traces would both run, according to their descriptions, in the superior medullary rays. If we return to Williamson's original statements {oj). cit., 1871 and 1878) that the strands running in the upper medullary rays belonged to branches, the difficulties are just as great ; for hei'e, too, since the strands of the lower internode gener- ally alternated with those of the upper, the branch falling in the interval between the two upper strands would be exactly over a lower strand, but from the lower strand the leaf- 180 EDWAED C. JEFFREY ON trace oi'iginated and i;ouse([uently the Ijranch would lie in the axil of the leaf, which is not the case. If the cause he sought of all the manifold contradictions, which, assuming the correctness of the writer's course of argument, are present in the figures and statements cited above, it is to be found in the fact, that the figures in (question are inverted, in other words, in the fact, that, contrary to what is the case in Equisetum, the branches of the Calamites are represented as originating above the nodes, and by inverting the figures above mentioned all the difficulties which have been described at once disappear. It may be further stated, that it is only possible for the branches to uniformly alternate with tlie leaf-traces, whether the arrangement of the strands at the nodes is continuous or alternating, wlien the former originate between the strands which run up to the nodes, since it is from these same strands that the leaf-traces are derived both in Calamites and Equisetn. But if the conclusions of the last paragraph be accepted as correct, Williamson's areas of macerated parenchyma no longer lie below the node, and consequently cannot be used as an explanation of the tubercles occurring below the nodal constrictions of calamitean medullary casts. At this point the following quotation from Renault [op. clt., p. 89) may be intro- duced apropos of photograph 1 (Pi. 28, lig. 1), copied from his monograph {op. clt., atlas, pi. 47, fig. 7). "Les lames de tissu fondamental qui scparent les coins ligneux s'elargissent a leur partie snperieure o planche 47 fig. 7, 8 (ces deux figures doivent etre vues retournees) et forment une sorte de gouttie'"e ou de canal allant de la moelle Ti la peripheric; en coupe transversale ces organes out une section elliptique ; il n'est pas rare de trouver une cavite dans la region centrale, produite par la disparition, de celkiles polyedriques qui forment une sorte de moelle (M. Williamson les a designes sous le nom de infrano- clal canals): les cellules qui coniposent la couche peripherique sont allongees dans le sens radial, prismatiques, polygonales sur une coupe transversale et rectangulaires sur une section faite suivant leur largeur, leurs parois portent des ornements ponc- tues; il est assez frequent de voir des tracheides se detacher des coins ligneux, penetrer au milieu de ce tissu particulier et se confiDudi-e avec lui, leur nondjre est egal a celui des lames de tissu fondamental secondaire qui separent les coins ligneux. Les racines adventives, quand elles se developpaient, etaient en rapport avec ces organes, que nous considerons comme des organes particuliers expectants, que nous distingue- rons sous le nom d'organes rhiziferes.'' The three important features of this citation are, that Renault states that his figure, which is reproduced in our j)hotograph 1 (PI. 28, fig. 1) , should be inverted. THE GENUS EQUISETUM. Igl that the traces riiniiing in the mediinary rays are related to roots, and that they are equivalent to Williamson's infraiiodal canals. Renault gives no reasons for the inversion, but obviously the figure, in its original position, is open to the same objec- tions as have been urged in a former paragraph against tlie orientation of the similar figures of Williamson and Scott. The observation tliat the organs, o, have a parenchy- matous medulla which is surrounded by a zone of pitted cells comparable to the peculiar tracheary elements of the basal node of the branches, or of the walls of the rhizophorous pedicels of P]quiseta is all the more interesting, because, as Renault informs us, roots are actually attached to these organs. It is possible to accept his first two statements, without admitting the accuracy of the third, viz., that the organs, o, are the equivalents of Williamson's infranodaf canals. If the reasoning of a former paragraph is sound, the tracts of macerated parenchyma which Williamson called infranodal canals are not really below the node at all but on the contrary al)ove it, consequently the organs described by Renaidt cannot Ije considered as their equivalents. If Renault's figure, reproduced in photograph 1 (PI. 28, (ig. 1), be compared with photographs 5 and 0 (PI. 27, figs. 5, 6), it is not very difficult to decide that the organs situated in the upper (really lower) medullary rays of the three figures are equivalent, and since, if the course of reasoning adopted here' is correct, these organs in photographs 5 and 6 (PI. 27, figs. 5, 6) are branches they must similarly be branches, or their homologues, in photograph 1 (PI. 28, fig. 1) . But Renault tells us, in the passage quoted above, tliat in this case they are related to roots, and the inference may be drawn, that they are the morphological equivalents of the rhizophoric bud^s of Equiseta, which have an identical relation to the vascular strands and to tlie nodes. Renault (op. cit., texte, p. 92, 95, 107, 123) has not realized this, since both in his figures and the subseqviently puljlished explanatory text he makes the traces of the ordi- nary branches pass outwards above the leaf-traces and above the node, and not below the leaf-traces and at the node, as must be the case if the mode of the argument previously adopted by the writer is not fallacious. At the beginning of the discussion of the relation of calamitean brandies to the node, a figure from Weiss, our photograph 0 (PI. 30, fig. 6), was cited, indicating, if the writer has properly interpreted it, that externally at least the branches of the Calamites had the same relation to the node as obtains in living Equiseta. A consideration of the internal features has led, moreover, to a similar conclusion in regard to the position of the Ijranehes in the ancestors of the Equisetaceae. In the case of the calamitean rhizophoric organs on the other hand, first from the evidence of internal structural arrangements, the con- clusion has been reached that they are the equivalents of branches and have the same relation to the nodes, PI. 2(i, fig. 17, which is a copy fnmi Weiss (Steinkohlen-CMlinnnrien, 182 EDWARD C. JEFFREY ON Heft 1, p. 121) sliow.s clearly that the roots ami branches were on the same side of the nolle in the Calamitcs, externally as well. In the center of the figure to the left are seen a few small leaf-scars. Along the rest of the nodal line these have disappeared. Below the indications of leaf-traces stretches a line of scars, the smaller of which are root- scars the single larger one is a branch-scar, below which are the less distinct scars of its basal I'oots. Assuming the correctness of the various arguments employed in attempting to solve these difficult questions of calamitean anatomy, the result is reached, that in the Calamites the branches and their morphological equivalents, the rhizophoric organs, had the same relation to the nodes as in living Ec[uiseta. Further, tlie branches were more or less exactly centered on the node according as they were of greater or smaller size. The rhizophoric oi'gans were attached along the lower margin of the ring of nodal wood, and their cylindrical medullary cavities, which, unlike those of iu>rnial branches, did not expand are consequently represented on the casts by nodules situated below the nodal constrictions. The infranodal tu))ercles are thus only to be found on subterranean stems, and this is in accordance with Weiss's statement {op. clt., Heft 2, p. 24) referred to in the Introduction, that they are absent or inconspicuous on axes, which are clearly recognizable as aerial. An attempt has been made in the foregoing jiaragraphs to explain certain featiu'es of the Calamites by reference to the corresponding features of living Equiseta. The writer will now emjjloy the reverse method of attempting the explanation of certain structural features of the extant genus Equisetum by a consideration of the homologous ones of the ancestral and extinct Calamites. The Cladosipiioxy of the Equisetaceae. Attention has heen called in the early part of this essay to the peculiar relations of the leaf-traces in Equisetum to the nodal wood viz., that they originate below it and yet without causing any gap or lacuna in its vascular ring, as might be expected from the analogy of the foliar lacunae of the Filicales, which occur immediately above the exit o£ the leaf-traces from the vascular tul)e. Yet, notwithstanding the fact that the lacunae do not begin at the level of exit of the leaf-traces, they do, nevertheless, occur opposite the outgoing traces, Ijut ordy make their appearance above the nodal wood. These facts have already been referred to in connection with photographs 5 and G (PI. 28, figs. 5, G) . They appear not to have Ijeen noticed by previous writers and are susceptible, neverthe- less, of a somewhat interesting interpretation which is of importance from the stand- point of the phylogeny of the Equisetaceae. THE GENUS EQUISETUM. 183 III the Introduction attention has been called to the characteristic arrano-ement of the traces at the nodes in Archaeocalainites, which is diagramniatically represented in PI. 26, fig. 10. It is to be noticed here that the leaf-traces are not opposite lacnnae at all, but, on the contrary, the branches or their equivalents, the rhizophoric organs, are. In this primitive type of Calatnite the leaf-traces were not subtended by any gaps in the vascular tissues, but the internodal lacunae were ramular lacunae and appeared ininiodiately above the brandies. In the Introduction the term cladosiphonic lias been used to describe a tubular fibrovascular axis characterized by having ramular lacunae but no foliar lacunae, and consequently Archaeocalainites, like Selaginella laevigata and Lepldodendron harcourtii, is cladosiphonic. But Stur {oj). cit., p. 158) has shown that in the Ostrau beds, passing from lower to higher strata, a series of forms, Galamltes ramifer Stui", C. cisiiformls Star, C. approximat'iformis Stur, and C. ostravlensis Stur, represent transitions from the bundle arrangement of Archaeocalamites represented in PI. 1, fig. 15, to that of Equisetum represented in Pi. 1, fig. 16. It will consequently be not unreasonable to infer with Stur, that the equisetal arrangement of the bundles was derived in the coarse of geological time from archaeocalamital arrangement. The final result of the shifting of the internodes upon each other at the nodes has been, that the lacnnae primarily belonging to the branches no longer subtend the latter but on the contrary the leaf-traces, which still, however, betray their true morphological relations by the fact that their exit causes no break in the nodal wood. It may then be assumed, if the reasoning based on these facts is correct, that the apparent foliar lacunae of Equiseta are really ramular lacunae which have shifted from their orio-inal position during the course of evolution of the Equisetales, and that this group is accord- ingly cladosiphonic. The original state of affairs occasionally reappears even in modern Equiseta, as is shown in photograph 4 (PI. 29, fig. 4) . A much more striking example of the same ancestral phenomenon is shown by photograph .3 (PI. .30, fig. 3), which reproduces the course of the vascular strands in the cone of Equisetum arvense. It will be noticed that the bundles in this case for the most part do not alternate. This feature is more or less marked in the cones of all the species of Equisetum which have been examined by the writer. In this connection may be mentioned a striking cambium- like arrangement of the cells in the young bundles of the cones of E. hiemale and E. limositm. It disappears, however, almost entirely in the comparatively massive bundles of the adult cone, and perhaps may also be regarded as an ancestral feature, since secondary growth was frequently present in the vascular tissues of the stroliili of various Calamites. It has been pointed out in the Introduction that protostelic and siphonostelic axes may be possessed by different species of the same genus e. r/., TA'pidodcndron selaginoides 184 EDWARD C. JEFFREY ON was protostelic and L. harcoifrfii was siphonostelic, likewise SujUJaria vasmJaris and S. 2ndcherrima had iDrotostelic axes, wliile on tlic otlior liand S. dipJoxylon, S. (']c<, and S. sjrhmlosa had sijihonostelic axes ; a similar relation exists between Sehujludla VKirtcnsil and *S'. lueci(j(it^iN 17 1901 ^H<5innateJy or tricho- tomously branched, have a subcylindrical, or subconical, gelatinous support continuous to the tips of the p>rincip)al branches, are provided with numerous club-shaped vesicles among the oral funnels, and are without appendages on the dorsal, or abaxial, side ; also with four interradial gonads in the aboral wall of the four separate subgenital cav- ities; sixteen margined sense organs {rhopalia); and thirty-tioo radial canals connected by a network of anastomosing branches. For the sake of clearness this definition is made to include the characters of the family Toreumidae Haeckel, to which this genus belongs, and the purely generic charac- ters are italicized. Cassiopea xamachana.' Cassiopea xamachana Bigelow, Zool. Anzeiger, no. 393, 1892, pp. 212-214. (?) C.frondosa Fewkes, Bull. mus. comp. zool., vol. 9, no. 7, 1882, pp. 254-259. Diagnosis. — A Cassiopea with a disc-like umbrella, concave on the aboral side; when regular, with eighty short and ol^tuse marginal lobes separated by deep grooves on the surface of the exumbrella (in each of the sixteen parameres three velar lobes between two ocular ones) ; wliite markings on the exumbrella, consisting of a circular Ixand with a diameter somewhat greater than that of tlie concavity, within this sixteen oval or elip- tical spots lying in the radii of the rhopalia, and on the outer side eighty marginal spots, one for each marginal lobe ; oral arms rounded and slender, never angular, exceedino- the radius of the umbrella by at least one half of its length, and bearing nine to fifteen primary branches which are, in turn, copiously branched, giving the whole appendage a spatulate outline ; very numerous small oval vesicles attaclied at tlie axils of the small branches and thickly massed upon the oral disc of adult females; and many small and a few large, flattened, linear vesicles attached one at the axil of each of the larger branches ' This name, suggested by Professor Brooks, must stand as printed in the preliminary description of the species, according to the cm-rent rules of nomenclature, followed by the Boston Society of Natural History. But it should have been written xamaycana, from Xamayca (the x is pronounced like ch in the German ach), the Indian name for the island of Jamaica, as written by the early Spanish historians (see Herrera, Novi orbis pars duodecima, sive descriptio India; occiden- talis, 1024 ; also Encycl. Brit., Pth ed., article, Jamaica). The form Xaymaca given by Bridges, Annals of Jamaica, 1827, and followed by several subsequent authors, is probably a misprint. CASSIOPEA XAMACHANA. 195 and to the canals on the oral disc, the thirteen largest vesicles being one at the axil of the largest branch on each arm and one at each junction of the canals on the oral disc ; oral funnels entirely wanting on the oral disc in adult females, Ijut present in immature specimens. Special descrijytioii. — A detailed account of the anatomy of this species will be given in the anatomical portion of this paper. It is intended here to call attention merely to the features that distinguish our species from its nearest allies. Cassioj^ea xamachana resembles very closely two medusae that inhabit the Red Sea and Indian Ocean, Cassio'pea andromeda Eschscholtz and C. po{i/poides Keller ('83) , but it seems, nevertheless, to be distinct from either. Upon comparison with the descriptions of C'C^slopca andromeda given by Tilesius (29), Haeekel ('79), and Vanhutt'en ("88), and with the figures of Tilesius ('29) and Forskal (1776) , C. xamachana appears to differ from this species in the following particidars : The exumbrella is not merely flat, but is concave ; besides the ninety-six white sjiots on the exumbrella, there is a fjroad circular band of white nuire or less connected with all of tlie marginal sjiots (Fig. 35), the oral arms are more thickly branched and are longer, exceeding by one half to two fifths the radius of the innbrella, instead of being only one third longer; moreover the arms have none of the flattened appearance figured by Tilesius and mentioned by Haeekel. C. xautachana differs from C pohipoldes in having more slender oral arms, with five to seven pairs of branches instead of three, and with fewer very large vesicles, and these apparently not so large and always flattened. The color pattern in the two species is nearly the same, except that in C. xamachana the three white spots on the three velar lobes of each paramere are seldom widely separated from the circidar ))and of white. The colors in the pattern, however, differ considerably in the two species. The ground color in C. xamachana is never light brown, but is always much darker, a greenish brown, usually with a distinct shade of blue on the subumbrella. The large oral vesicles are never sky-blue, rose-colored nor white, but are yellowish green, often with a bluish green stripe; and, wliile the margins of the oral funnels are deep brown, they are always fringed with the white digitella. C. xamachana is easily distinguished from C. nniafa Haeekel l)y the presence of large oral vesicles and by the more extensive branching of the arms ; and it diff'ers from C. mertemiii Brandt ('38), ('. deprensa Haeekel ('80), and C. picta Vanhiitt'en ('88), in the number of marginal lobes on the umbrella. C. ndrosia Agassiz and Mayer ('99) iliffers also in number of marginal lobes and in coloring. Fewkes ('82) has described a medusa from Key West and the Tortugas under the name " C'«.s',sio/je« frondosa Lamarck," which he regards as identical with PolyclnnUi frondosa Agassiz. From the description given by. 196 ROBERT PAYNE BIGELOW ON Fewkes it is impossible to identify his species positively. But a comparison of his figures Avith living specimens of both sexes of P . frondosa shows at once that the two species are distinct; while a comparison with C. xamachana shows so close a resemblance that I am inclined to think that Fewkes has discovered one of the varieties of our species, described in the next section. Not only is P. frondosa perfectly distinct from C. xama- chana, but I think we are justified in retaining the former, for the jDresent at least, in a separate genus ; and there can be little doubt that Lamarck's Cassiopea frondosa dwell- ing in the " Ocean of the Antilles " with its " marglne decein-lohata " is none other than Agassiz's Polyclonia frondosa. Therefore, even if it should ])e proved that the form described by Fewkes is the same as the subject of the j^resent memoir, the name that I have given to it will hold, nevertheless, as the designation of the species. Variations. — If we compare the average dimensions of various organs, expressed in thousandths of the diameter, with the maxima and minima, as may be done by examining the third, fourth, and fifth columns in Table 1, p. 201, it becomes evident that there is a very consideraljle amount of variation in the relative size of parts of C. xamachana. In the oral arms, not only does the relative size vary, but the number and the arrangement of the branches are both variable. Moreover this vari.ibility exists between the ditt'erent individuals. In nineteen specimens examined the maximum number of branches found on one arm was sixteen, the niininium nine, and the greatest difference on any one individual was four. The most striking variations in C. xamachana, however, are to be found in the structures at the margin of the umbrella. These are highly variable in this species, and have been found to be variable, although to a less extent, in other medusae. It is unfortunate, therefore, that in his beautiful systematic work on the medusae Haeckel should have found himself forced to distinguish the genera chiefly b}' differences in the marginal structures. He himself notes the variability in the number of parameres of Polyclonia frondosa. Agassiz and Mayer ("99) found in one specimen of C. ndrosia eighteen rhopalia, and in another twenty-two. The number of rhopalia was counted in twenty-seven specimens of C. xamachana. Of these ten were found to have sixteen, the typical number for the genus, and twelve had more than sixteen, three having seventeen, and three more, eighteen. The largest number on one individual was twenty-three. There were five specimens with fewer than sixteen rhopalia, but only two had less than fifteen, and both of these showed correlated abnormalities in the mouth parts and snbgenital cavities. One had fourteen rhopalia, four oral arms, and two subgenital cavities and gonads. The other had ten rhopalia, only five oral arms, with three oesophageal canals leading from the stomach to the canal system of the arms, and three normal subgenital cavities and one very small vestigial one (Fig. A.) . CASSIOPEA XAMACHANA. I97 Redundancy of mouth parts is not nearly as common as of tlie marginal structures. Only two cases were observed. One specimen with an additional pair of oral arms in one interradius had seventeen rhopalia. The other had eleven arms, with five subgenital spaces and gonads, and this one had twenty-two rhopalia. On the other hand, five speci- mens were found with twenty or more rhopalia, and perfectly normal mouth parts. It will be seen, then, that the number of rhopaha, which has been taken as the principal generic character in the group, is a highly variable one. The number of Fig. A. Section through the stomach of a specimen witli only 10 rhopalia and .5 oral arms, to show the abnormal arrangement of gonadia and oesophageal canals. In the region marked a the margin of the umbrella presents a wide space in whicli there are no rhopalia. go = gonad. For explanation of the other lettering see Explanation of Plates. marginal lobes in each ^oaramere has been taken as one of the principal specific characters, and this is, likewise, highly variable. The variation consists principally in the interpolation of a small secondary lobe betAveen two typical ones. Even in a regular and typical specimen, such as is shown in Fig. 35, the position that would be taken by these secondary lobes is indicated Ijy small ridges on the dorsal surface. A specimen with a large number of rhopalia is as likely to have the marginal lobes in each paramere arranged typically ;is one having a smaller number. Conversely, a specimen with fifteen to seventeen parameres is as likely as not to vary from the typical form. The variation may consist in the addi- tion of two secondary loljes in the paramere, the addition of four lobes, or in a (|uite irregular arrangement ; and this modification may affect all of the parameres alike or only a portion of them. Througliout all of these modifications of tlie margins there is manifested a constant regard, as it were, for the symmetry of the parts. It is very seldom that an additional rhopalium appears as if attached fortuitously in some irregular way. Almost always either it is in the midst of an entirely new paramere or else there is a distinct line of symmetry running between two adjacent rhopalia that evidently correspond to an originally single one. In other words, a jjaramere has been incompletely doubled, and the two parts are 198 ROBERT PAYNE BIGELOW ON bilaterally sjiniiieti'ical to one another. We find all degrees of this doul)ling in the adult from a double-headed rhopaliuni ^ to two complete parameres, and the same process may be seen in the forked tentacles frequently found in the larvae (Figs. 14 and 21, x) . With the exception of the forked tentacle and the double-headed rhopalium, these stages of duplication are well rejiresented at ti, ir, ,»■, y and z in Fig. 30. The radially arranged stripes and sjjots on the eximibrella, which, with a circular band, foi'm the color pattern described in the next section, vary in number with the rhopalia and marginal lobes. But when two rhopalia are close together there may be only one corresponding rhopalial stripe, and it will then occupy a position intermediate between the two. For example, in the specimen mentioned before as having only ten rhopalia, two of the rhopalia were very close together and there was but one rhopalial stripe corresponding to them. The other' I'hopalia were evenly spread, except that they were absent from one rather wide section of the circle. The rhopalial stripes, nine in all, were placed in a corresponding manner, and were absent from the corresponding area. There is also a wide degree of variation in the extent of fusion between the circular band and the marginal spots. The spots on the velar lo))es are usually not fused to the circular band in young specimens, and they frequently remain distinct in adults. It was found, however, that this is more usually ti-ue of specimens from the Salt Pond than of those from Port Royal. I thought that 1 could see, also, correlated differences in the sizes of certain of the mouth parts, and I was thus led to in([uire if there were a division here of the species into two races. For this purpose Table 2, p. 201, was constructed. From this it will be seen that the specimens from the Salt Pond (var. ^ 1 ) have on the average longer oral arms and shorter vesicles than the ordinary specimens from Port Royal (var. B) , while the stomach is of the same size in the two groups. Whether these slight differences are in any way connected wath the probable difference in density of the water in the two localities, experiment alone can determine. In the third column of this table dimensions are given of some specimens from Port Royal (var. C) that are so different from the rest that they might be regarded as of a distinct species.^ Suspicion of their being merely sports is aroused, however, by the fact that- only two specimens (female) were found living among a large number of the usual form. The most striking peculiarity of these two specimens was the great number (forty to fiity) of uniformly large oral vesicles, two to four centimeters in length, scattered over ' Fewkes, ('82) has observed fiimilar double-headed rhopalia. and it is on account of the variability of the marginal structures that lie regards Polyclonia as merely an abnormal Cassiopea. ' It is po.ssible that this variety nuiy be the same as Caxsiopen frumlosa Lamarck of Fewkes, although his ligures do not show any large vesicles on the proximal parts of the oral arms. CASSIOPEA XAMACHANA. 199 the whole extent of the mouth parts. Among them the central, radial, and prmiary vesicles were hardly distinguishable, although so easily recognized by their greater size in the typical form of the species. Another peculiarity was a projection of the mesogloea on the oral side of each subgenital osteuni, so that tlie interradial diameter of the oral disc was considerably longer than the radial diameter, as shown in the table. Tliese specimens presented also some peculiarities of coloring, which will be noted in the next section. Color. — The coloring of this semi-transparent animal consists of certain white mai'k- ings, together with shadings of sul)dued tints of In-own, green and blue, that are often very beautifid. If we turn the aboi-al side (Fig. 35) of the medusa toward us we find often a brown- ish band encircling the disc at the periphery of the concavity and shading off gradually on both sides. Deeper within the mesogloea there is a much wider white circular band extending under the brownish one ; and white bands, or spots, extend in a radial direction outward from this along the marginal ridges. There is one spot to each ridge, and it reaches nearly to the tip of the marginal lobe. The bands on the rhopalial lobes are inter- rupted, however, by a roughly circular, transparent area over each rhopalium ; and in many specimens, especially young ones, the interrhopalial (velar) spots are not fused with the circle. On the inner side of the circular band of white there is a circle of large white spots, "rhopalial spots," or stripes, that lie deep in the substance of the exinnbrella and are visible through the mesogloea, one in the radius of each rhopalium. The spot is elliptical in outline, and extends from the white band to a point about two fifths of the distance between the periphery of the concavity and the edge of the stomach. These spots, while usually continuous with tlie band, like the marginal spots, are not always so. At the centre of the umbrella the stomach and subgenital cavities may be seen through the mesogloea as a reddish brown circular area with a diameter of about one fourth of the total diameter of the disc ; wliile surrounding the stomach there is a deep blue halo with points that extend outward between the last-mentioned bands of ^Vhite. Now if the animal be allowed to return to its usual position, the subumbrellar siu'face will be found to be jDretty evenly stippled by the greenish brown cells in the mesogloea. Apparently beneath this stippling there is a blue pigment forming a circle around the margin of the stomach and extending outward in l)road bands, one along each interrho- palial radius, nearly or quite to a large, more or less distinct patch of blue, that lies close to the margin between every two rhopalia. The i-adial canals, and the fine, connecting network of tubes, appear as rather indistinct, opaque, white lines. The mesogloea of the oral arms is transparent and colorless, except for an opaque white stripe beneath the dorsal surface of each arm, of the same chai'acter as the white 200 llOBERT PAYNE BIGELOW ON markings of the umljrella. There is a similar stripe on the dorsal side of each of the larger branches which may, or may not, be continnous with the stripe on the main stem. The bases of the oral funnels are of a delicate blue coloi", which often extends to the bi'achial canal. The margin of each funnel is a deep brown, that shades off over the blue ; while the small tentacles, or digitella, that spring from this mai'gin are pure white. The larger tongue-shaped vesicles on the arms and oral disc have a greenish yellow color with a bluish green longitudinal stripe. The smaller vesicles on the arms are colored in a similar way and are inconspicuous, but the cluster of very small vesicles that occupy the greater part of the oral disc has a very different appearance, being lightly tinted by fine reddish brown pigment spots. The two specimens that I have called variety C, are somewhat differently colored. The markings are yellowish Avhite. The circular white band is indistinct. The rhopalial bands are interrupted at the margin of the concavity of the exumbrella, and stop short about half a centimeter from the rhopalial hood. At the margin of the umbrella there is a white spot on each rhopalial lobe and a strap-shaped spot on each velar lobe. The centre of the umbrella is whitish and opaqvie, so that the stomach does not sliow through. The oral arms are translucent, milky white tinged with brown, and without distinct white markings, except on the dorsal side of the principal branches. The large oral vesicles are yellow and greenish yellow, with a brown centre. Size. — The diameter of the largest specimen found is 24 cm., while the smallest specimen that contained eggs measured 6.5 cm. The average diameter of twenty-thi-ee adult specimens was 1.3.7 cm. The relative sizes of the parts are exhibited in the follow- ing tables. Table 1 shows what may be regarded as the normal proportion for the species, though, to be sure, some of the measurements were made only on Port Royal specimens. Some of the dimensions were measured on a smaller number of specimens, and for these the average diameter of the umbrella of the specimens on which these measurements were made is given separately to show the correct proportions. Table 2 furnishes a means of'comparing the proportions in the three varieties. CASSIOPEA XAMACHANA. 201 TABLE 1. DIMENSIONS OF SPECIMENS FROM BOTH SALT POND AND PORT ROYAL (VARIETIES A AND B.) Number nf Avera^iO tli- .Vverai^c dimensions Maxinuiin Mininuim siK-H-iniens HH'iisions in in llit.nsaudtlis of (In tltousancltl s of diainetpr Remarks measured eelUlliietf|-s average diameter unless iitlierwise noted) Diameter of umbrella 21 14.33 1000 24 cm. 9 cm. Length of arms meas- ured from centre of Salt Pond and oral disc '21 11.21 782 888 042 Port IJoyal Length of central specimens tak- vesicle 21 2.71 189 287 103 en together. Length of primary vesicle 21 1.82 126 190 71 Diameter of umbi'ella 10 15.79 1000 24 cm. 12 cm. Length of radial Port Royal only. vesicle 10 3.01 190 250 117 Diameter of umbrella 11 13.62 1000 16.3 cm. 6.3 cm. Salt Pond and Diameter of stomach 11 4.22 311 333 292 Port Royal. Diameter of umbrella 3 1 8.0(5 1000 24 cm. 15 em. Thickness of umbrella 3 1.33 71 73 70 Port Royal. Total depth 3 3.59 191 212 173 Diameter of umbrella 2 20.50 1000 24 cm. 17 em. Port Royal. Diameter of oral disc 2 8.00 390 441 354 TABLE 2. AVERAGE DIMENSIONS OF THE THREE VARIETIES, GIVEN IN THOUSANDTHS OF THE AVERAGE DIAMETER OF THE UMBRELLA. Variety ^— Salt Pond Variety U— Port Royal Variety C— Fort Royal Length of arms 850 715 818 Length of central vesicle 157 217 Radial vesicle 190 163 Primary vesicle 112 138 167 Diameter of stomach 298 311 322 Thickness of umbrella 71 80 Total depth 191 213 Radial diameter of oral disc 390 394 Interradial diameter of oral disc 390 470 Locality. — Great Salt Pond, and mangrove swamps (" The Lakes") in the rear of Port Royal, Jamaica. — Bigelow. (?) Moat outside Fort Jefferson on Garden Key, Tortngas Islands, and Mangrove Keys, near Key West, Florida. — Fewkes. 202 ROBERT PAYNE BIGELOW ON Anatomy. Form of the Body. — To one who is familiar with the cyaneas, aurelias, and the like, of our northern coast, the shape of this medusa appears very strange. The aboral, or exumbrellar surface (Fig. 35), instead of being convex in Cassiopea xamachana, as it is in the great majority of medusae, is concave when the animal is at rest, except for a slight convexity over the stomach, and except in the region of the thinner marginal part of the umbrella, where also it is convex. The surface of the subumbrella, on the other hand, is convex, except in this same thinner marginal area, where it is in turn concave. The umbrella thickens very gradually from its margin to the centre, and the elevations and depressions of its surface have very gentle slopes, so that its general shape is much nearer that of a flat disc than the dome-like form of ihost medusae (Fig. 35) . A circular column arises from the centre of the oral surface of the umbrella. It is broad, but very short; and a few millimeters from the umbrella it loses its circular 'outline, owing to eight stout arms that spring from it at regular intervals (Fig. 34) . These are smooth and rounded, except along a line on the oral side, where they bear the fringe of oral appendages, and they are long and much branched. This column is the oral disc, and its arms the oral arms. 21ie Structure of the Mesogloea. — By far the greater part of the mass of the oral arms and disc, as well as the umbrella, is composed of a firm, elastic, gelatinous substance, the mesogloea, and it is to this that the shape of the body is due. The description given by Keller ('83), of the structure of the mesogloea in C. poly- poides would apply almost equally well to our species. The mesogloea consists of a hyaline matrix, in which are imbedded certain fibres and three kinds of cellular elements. Most of tlie fibres appear to be analogous to connective tissue fibres, and take a general course through the mesogloea at right angles to the surface. Others seem to be proto- plasmic. At any rnte, they nuiy be observed to proceed from the star-shaped cells that are scattered throughout the jelly. The cellular elements are : the star-shaped cells, just mentioned; vesicular bodies, found in certain restricted localities ; and the green cells, which, as it will be shown later, are symbiotic plants. The star-shaped cells remind one of osteoblasts, and are probably analogous to them, in that they are concei-ned in the formation of the jelly. Hamann ('8l) has called them colloblasts. They are small, often somewhat elongated, and have a well-marked nucleus. CASSIOPEA XAMACIIANA. OOH The vesicular bodies give rise to the white markings that were mentioned in the description of the species. These vesicles are much larger than the colloblasts. Each one seems to be made up of a wall of exceedingly minute refractile granules, surrounding a clear sj^ace. That this body is a cell, however, is shown by the presence of a nucleus pressed closely against one side. The green cells, or zocmthelae, are widely distributed throughout the mesogloea, but are most abundant in the umbrella. Tliey are not infrequently found imbedded in the endodermal epithelium. The living cells have a greenish brown color, which they impart to the animal as a whole. They are of considerable size, are globular, without projections of any kind, and are generally to be found in clusters of two or more (zaj Figs. 52, 56, and 63). Each one contains a nucleus and numerous granular bodies, and apparently is surrounded by a cell wall ; but the latter is hard to distinguish from the edge of the adjacent matrix. Keller thought that similar bodies in C. polypcAcles could not be algae, because he failed to find any evidence of a cellulose cell wall. He regarded them, therefore, as essential elements of tlie " mesoderm." In those of my specimens, however, which have been killed in Erlicki's fluid and stained with borax carmine, the nucleus of these cells is found to be red, while the gran- ular contents of the cell are bright green, and there are often one or two green bodies present tliat are as large or larger than the nucleus. They have all the appearance of chlorophyl bodies, and it is well known that the chlorophyl of some algae is not readily removed by alcohol. Moreover, in teased preparations treated with iodine solution these cells are found to be filled with granules that quickly turn deep blue, — evidently starch. The test for cellulose with iodine followed by sulphuric acid, gave, however, unsatisfac- tory results. The outline of the cell would become distinctly darker, but not recognizably blue. In the same way with chloriodide of zinc, a very marked reaction for starch was obtained, the granules becoming almost black ; but so long as the object was viewed by direct transmitted light, no reaction for cellulose could be detected with certainty. On the other hand, when the light was thrown upon the object obliquely by means of a condenser with a central diaphragm, the effect was quite different. The starch granules became a deep ultramarine, and the parts of the cell not occupied by the starch appeared distinctly violet, showing without doubt the presence of cellulose. Both starch and cellulose, as well as some form of chlorophyl, having been demon- strated in them, there can be no further question that the green cells in Cassiopea are symbiotic algae. The Oral Arms and their Branches. — The eight oral arms (Fig. 34) arise from the central oral disc at about equal intervals; and when an arm is extended, the distance 204 ROBERT PAYNE BIGELOW ON from the centre of the oral disc to the tip of the arm about equals three quarters of the diameter of the umbrella. But the arms are very contractile, and may be shortened to half this length. The arms are slender and graceful in shape, the mesogloea tapering very gradually to the tips of the finest branches. The branches are arranged alternately. The largest one, which is the first formed, is at a point about two thirds the length of the arm from its base. From this point the branches decrease in size gradually toward the base of the arm, and more rapidly toward the apex. The general outline of the arm, therefore, including its branches, is roughly spatulate. The Oral FunneU and Brachial Appendages. — Just below the surface of the oral side of each arm there is a longitudinal tube, the brachial canal, that ramifies to each branch, and finally opens to the exterior by funnel-shaped oscula {os., Fig. 3-f ) at the tips of the numerous ultimate branches, and at many places along tlie course of the tube. The margins of these oscula, or oral funnels, are provided with short tentacle-like projections, the digitella. These are covered by an epithelium containing nettle cells, and each has a gelatinous axis in which there are transverse plates of greater density than the rest of the jelly, and these give the structure the cellular appearance first described by Hamann ('8l) . The epithelium lining the tubes and funnels is ciliated. There open also into the brachial canals the lumina of the oral vesicles {v., Fig. 34) . These structures, as already stated in the diagnosis, have their points of attachment in the axils of the branches. All except the smallest are flattened laterally. The smaller ones are oval in outline, the larger ones linear. At one side near the apex there is a cluster of short processes that Hamann has homologized with digitella. The Oral Disc. — Although the eight oral arms seem to be placed at equal distances and to be alike, they are morphologically in pairs, each pair being homologous to one of the four lips of a semostomous medusa, — an aurelia, for example. The line that separates two members of a pair is therefore, according to Haeckel's nomenclature a perradius. The brachial canals from each pair of arms, on entering the oral disc, converge and unite into a single radial tube that is continued to the centre of the disc, where it unites with the other three. In this way the course of the tubes on the oral disc forms a pattern that resembles a Maltese cross. The larger central vesicle is attached at the centre of the cross. In a living specimen 11 cm. in diameter this measured 3 cm. in length. There are four other vesicles that most nearly approach the central one in size, and these arise from the radial canals near the junction of the brachial canals, and I have called them, therefore, the radial vesicles. In full-grown individuals there are eight more vesicles upon the oral disc, a little smaller than the last, one on each brachial canal distal to the junction. It is only near the periphery of the CASSIOPEA XAMACHANA. 2(lo disc that the canals are provided with oral funnels. For most of their course on the disc the canals give rise to the very small vesicles, finely sjieckled with a reddish brown pigment, that already have been mentioned. These have nettle batteries at their tips, and are so numerous as to cover completely the greater part of the disc and to hide the course of the canals. This mass of small vesicles, however, is not acquired until late. Specimens as much as 6 cm. in diameter will be found to be without them. In such specimens we have the five largest vesicles, and a number of oral funnels are scattered along the canals, just as they are upon the arms. This replacement of the oscula on the oral disc by small vesicles has been observed to occur also on adult females of PoJydonia frondosa, but not in the males (Bigelow, '93) . It is not improbable therefore that a similar difference between the sexes may be discovered in our species of Cassiopea. The Sicbgenital Cavities and the Digestive Tract. — At each of the four points of junction of the brachial canals there is a slit-like jjassage, oesophageal canal, dipping vertically into the mesogloea of the disc, and opening into the stomach. The latter is a lens-shaped cavity, with a gently arched roof. Its floor consists chiefly of four lozenge- shaped areas, where the body wall is very thin and plaited in radial folds (Fig. .34) . These thin parts of the body wall form the roofs of the subgenital cavities, which open to the exterior, each by an elliptical orifice, osteum, (x-, Fig. 34) in the side of the oral disc near the subumbrella and in the angle between two pairs of arms (interradial) . The gonad appears as a band which crosses this membrane tangentially at its greatest width. Just central to each gonad there is a multiple series of very many small gas- tric filaments forming a narrow band pai'allel to the ovary. These are ciliated, and provided with nettle and gland cells. The portion of the floor of the stomach not made up of these lozenge-shajjed membranes is bounded by the firm mesogloea of the oral disc. This area has the shape of a Maltese cross, and it is in tlie arms of this cross, between the subgenital cavities, that the passages from the oral canals open into the stomach. Near its periphery the floor of the stomach is marked by radial grooves. These are continued, each into one of the radial canals that extend outward from the edge of the circular stomach to the marginal region of the umbrella. There are regularly thirty-two of these, sixteen in the radii of the rhopalia, and sixteen interrhopalial. When the number of rhopalia is increased, the number of radial canals may or may not increase in proportion. There are often thirty-four or thirty-six of them. The canals in the radii of the" rhopalia are larger and more nearly straight than the interrho})alial ones, and all are connected by a fine network of anastomosing branches, among which no distinct circular canal can be recognized. The meshes in the network of canals are connected by a plate of endodermal cells, the eiidodermal lamella. This lamella is also in contact with the subumbrellar ectoderm along a line encircling the umbrella a short distance from its mar- 20G ROBERT PAYNE BIGELOW ON gin, so that there is a complete sheet of endoderm separating the subuiubrclliir fioni the exumbrellar mesogloea. Muscuhiture. — The exunibrella is devoid of musrles, but on the opposite side there is a continuous sheet of muscle fibres, which is spread over the subunibrella, except a narrow zone at its margin, and is continued over the oral arms to their finest ramifications, and also into the subgenital cavities. Most of the fibres on the subunibrella do not take an evenly circular course, but are undulating. They form in this way a series of double "arcades" like those found by Haeckel in other species of Cassiopea. There is one of these double arcades for each interrhopalial space. The surface of the mesogloea in this region is grooved. The sheet of muscle fibres, lies directly upon it, and is therefore corrugated, the grooves being parallel with the fibres. The muscular layer upon the oral arms is smooth, and its fibres take a longitudinal course, extending to the digitella and oral vesicles. In the subgenital cavities the arrangement of the muscle fibres could not be made out; but their presence was revealed by the squirming movements of the thin membrane that separates the subgenital cavity and bears the gonads and gastric filaments. Structure of the Marginal Sense Organs. — Each rhopalium has a pigment spot on the aboral side near the extremity, and each one lies in a deep sensory niche. The dorsal sensory groove, common in the Pelagidae, Aurelia, etc., is entirely lacking; although Keller found in C'.^Jo/_i//:*oi(ies a slightly depressed thickening of the ectoderm that corresponds to it. The sensory niche and rhopalium are, with the exception of the pigment spot, similar in all essential particulars to those found in Pelagia. The rhopalium is the only organ in the sensory niche (Fig. 5G). It is a hollow, hnger-like projection attached by its base to a low ridge that runs along the roof to the central wall of the niche. This ridge is penetrated longitudinally by the continuation of a radial canal from the stomach, and the lumen of the rliopalium opens into the distal end of this canal. In the distal half of the rhopalium the lumen is nearly obliterated by the increase in thickness of its endodermal lining. Here the endoderm, instead of being a columnar epithelium as elsewhere, is a mass of parenchyma-like cells, each of which contains a large calcareous concretion, a so-called otolith. A thin, supporting membrane separates the endoderm from the ectoderm. At the distal extremity of the rhopalium the ecto- derm is a thin, cuboidal epithelium, while over the rest of the surface it is a thick, sensory epithelium resting on a thick network of fine nerve fibres. This, in turn, rests on the supporting membrane. I have observed no ganglion cells in this layer of nerve fibres, which is continued under the epithelium of the rhopalial ridge to the central wall of the niche, where it becomes imperceptible. There are no thickened bands of these fibres CASSIOPEA XAMACHANA. 207 running to ciliated pockets, such as are found in Dactylometra (Bigelow, '90) , and the fibres probably spread out finally into a thin network underlying the general epithelium of the subumbrella. The one feature in which this rhopalium differs from what is found in Pelagia is the presence of the pigment spot, already mentioned, lying on the aboral side of the rhopalium immediately above the centre of the mass of concretions. This area is probably sensitive to light, but it only differs from the rest of the sensory epithelium in that here the superficial cells are deeply colored by a yellowish brown pigment. A more careful examination would undoubtedly show the histology of this structure to be similar to what SchewakofF ('89) has found in Aurelia. Habits. The species of Cassiopea and the closely related genus Polyclonia find their habitat usually in quiet lagoons among the mangroves along the shores of the tropical seas. The mode of life of several species has been described by Brandt ('38) on the authority of Mertens, L. Agassiz ('62) , Gray ('69) , A. Agassiz ('81) , Archer ('81) , Fewkes ('82) , Guppy ('82) , and Agassiz and Mayer ('99) . Castiiopea xamachcma is no exception to the rule either in its hnbitat or its sedentary mode of life. When the young medusa is set free from the strobila it is an active swimmer. It gradually' becomes less active as the mouth parts acquire their adult structure, and by the time the animal has reached a diameter of two centimeters it has definitely taken up its abode upon the bottom. It lies there, as described in the Introduction, with the oral appendages upward, and seldom changes its position unless disturbed. The con- cavity of the exuml.)i-ella is an important aid in maintaining this posture against the action of waves and currents. The gelatinous tissue is firm and elastic, and causes the umbrella to assume its normal shape when the subumbrellar muscles are relaxed. The slight suction thus produced when the medusa comes to rest on a flat surface gives it such a hold that a certain amount of force is required to remove it. Usually, however, the water in the lagoons is very quiet, and there is more danger from its stagnation than from its motion. A Cassiopea is enabled to avert this danger by the slight swimming movements of the thinner marginal part of the umbrella. By means of these rhythmic contractions the water is drawn in on all sides, and then is driven upward and away. A healthy specimen lying undisturbed on the bottom of an aquarium was observed during seven minutes to make on the average 19.7 contractions of the umbrella per minute. In this way the animal is enabled to dr?iw to itself a fresh supply of oxygen and of its minute food material. 208 ROBERT PAYNE BIGELOW ON The oral arms and their branches are usually spread out so as to cover the sub- umbrella completely, but they are almost always in motion, bending to one side or the other, and they may be flexed aborally until the tips come within the umbrellar margin, or extended until they reach far beyond. Besides these general movements, the various appendages of the oral arms have movements of their own. Muscular con- tractions may be observed also in the thin membrane that separates the stomach from the subgenital cavities, and they probably serve to renew the water that bathes the gonads. When the oral disc has been severed from the umbrella, both parts may remain alive for several days, and both retain their powers of spontaneous movement. The first effect of the operation is often to throw all of the parts into a strong tetanus, but shortly afterwards the pulsations of the umbrella may be renewed at a rate considerably more rapid than normal, — 32 to 34 per minute in one case. When the medusae have been for some time under unfavorable conditions, it frequently happens that the part of the body-wall surrounding the periphery of the stomach is ruptured, and thus the mouth parts as a whole become separated automatically from the umbrella.^ While at Bimini, Bahamas, in 1892, I observed that the food of Polyclonia frondosa consists chiefly of copepods and other small Crustacea, and that these are caught by the combined action of the oral vesicles and the oscula ('93, \>. 106). If a copepod strikes a vesicle, the vesicle bends quickly so as to cover the mouth of the adjoining oscu- lum, and the copepod is thus enclosed in a trap. Artificial stimulation would cause the same reaction. Experiments on Cassiopea xamachana made to determine whether or not this species obtains its food in the same way gave negative results. Stimulation of an oral vesicle causes only a slight bending on the side stimulated. Although these vesicles are provided with batteries of nettle cells near the tip, I was unable to see that they played any part in the taking of food. It may be that they are protective, but the sting is very feeble. Examinations of the contents of the stomach were almost equally unsatisfactory. The contents of twenty-two stomachs were examined, and of these fourteen contained only a clear, very viscous fluid and, in some cases, a few apparently ripe eggs, more or less distorted, some small, colorless cells, probably sloughed off from the endodermal epithelium, and green cells identical with the " zoanthelae '' found in the mesogloea. One or more copepods and other Crustacea were found in five specimens. In one of these one small amphipod was found, and in another the cornea of an unknown crustacean. ' While tliis paper is passing through the press a paper has appeared by E. W. Berger (1900), in which lie gives the results of experiments made by F. S. Conaut upon Polyclonia and Cassiopea to test the effect of removing the rhopalia. CASSIOPEA XAMACHANA. 209 Diatoms and other algae, exclusive of the above-mentioned zoanthelae, were found in four cases out of the twenty-two. Almost always the first impression on opening a stomach was that it was empty; and it was only by careful examination that the contents of the stomach could be discovered. In two cases, however, a considerable amount of material was found in the stomach. In one of these the stomach contained, besides the usual eggs, zoanthelae, debris, etc., the remains of many copepods, some nematods, a zoea, and some diatoms. In the other one there was found a compact greenish mass, about one centimeter in diameter, composed of grjinular debris and diatoms of various species, together with some desmids, Oscillaria, foraminifera, infusoria, Vorticella, and some fine filaments with spirally arranged contents. This species exhibits the power of regeneration of lost parts to a marked extent. Specimens were frequently met with in which branches of the oral arms, or even portions of the margin of the umbrella, had evidently been formed recently to replace parts that had been destroyed. Moreover, branches of the oral arms that had been cut off were observed to reg-enerate oscula and vesicles at the central end. Ontogeny. Historical Review. — Numerous studies upon the reproduction of various animals by budding have shown that the formation of organs in the bud may take an entirely different course from the development of homologous oi'gans in the sexually produced embryo. As the observations to be described in the sequel were made entirely upon larvae that were observed, or supposed, to be asexually produced, they cannot settle any of the disputed points in regai'd to the development of sexually produced larvae. Nevertheless it will be of interest to compare the sexual with the asexual mode of ontogeny, especially as the development of a scyphistoma from a bud has never before been fully described. The development of scyphomedusae from the egg has been studied in comparatively few forms. Several species of Aurelia have been studied by Sars, Haeckel, Schneider, Clans, Goette, Frank Smith, and Hyde. Two species of Cyanea have been studied by McMurrich and Hyde. A species of Chrysaora has been studied by Claus; and Kowalewsky, MetschnikofF, Krohn, and Goette have traced the very interesting abbrevi- ated development of Pelagia noctiluca. The nearest ally of our species that has been studied with any degree of completeness is the Mediterranean rhyzostome Cotylorhiza tuherculata, which has been the subject of investigation by Claus and Goette. From the description of the process of budding given in the next section, it will be 210 ROBERT PAYNE BIGELOW ON — d g- -g noted that the larvae produced by budding are set free in a form resembling planulae, and it is the planula stage in sexual reproduction which is the earliest that can be compared with any stage to be described in this paper. All agree that the planula of the Scyphomedusae is a more or less oval, ciliated larva, somewhat flattened on one side. It consists of two layers of cells surrounding a cavity which is completely shut off from the exterior. The first step toward the development of the scyphistoma is an in- vagination of the ectoderm at the posterior pole of tlie planula. According to Goette and Miss Hyde, the endoderm is invagina- ted at tlie same time in such a way that two endodermal pouches remain in the plane of the long diameter, — " Haupte- bene," Goette, — (Fig. B, and h-b Fig. D), one on each side of the invagination, while the endoderm is pushed entirely away from the oral pole in the plane of the short diameter (Fig. C, and c-c Fig. D). The ectodermal invagination is the oesophagus (Schlund) , its external open- iui!; is the mouth, and the endodermal evaginations are the first pair of gastric pouches. Soon an opening is formed (Schlundpforte) between the base of the oesophagus and the central stomach, and at the edge of the opening the ectoderm fuses with the endoderm. Then the sec- ond pair of gastric pouches is formed. According to Goette these are produced in Cotylorhiza and Pelagia entirely' from the ectoderm of the lower part of the oesopha- gus (Fig. F) . According to his view the lower edges of these evaginations coincide with the margin of the gastro-oesophageal opening (Schlundpforte) , and are therefore at the level of the upper edges of the first pair of pouches. As these pouches extend out- Figs. B-G. Two stages in tlic development of tlie mouth and gastric pouches in a sexually produced scyphistoma, according to Goette. Figs. B to D are sections in the three dimensions of space of a larva in which the oesophagus is invaginated and the first pair of gastric pouches are formed. Figs. E to G are similar sections of a larva in which the open- ing from the oesophagus into the stomach (Schlundpforte) has been established and the second pair of gastric pouches are in the process of formation. 6, c, li, etc., indicate the plane of Figs. B, C, D, etc. CASSIOPEA XAMACIIANA. 211 ward the ectoderm is pushed out until the priucipal radii) e-e and f-f, Fig. G) gradually become equal. This results in the formation of the flattened peristomal disc (Figs. E and F) . At the same time the wall separating the oesophagus from the first pair of gastric pouches (Taschenvorhang) is split upward until the openings into the two pairs of pouches are upon the same level, and the " Taschenvorhang " is reduced to a low ridge, while the oesophagus is very much shortened. Portions of the original lining of the lower part of the oesophagus persist as the covering of the inner edges of the septa which separate the four gastric pouches. The larva is now in what Goette calls the scyphula stage. He regards this stage as of great phylogenetic importance, showing clearly, he thinks, a close genetic connection between the Scyphomedusae and the Anthozoa ; so that these groups should be placed in a single class, Scyphozoa, to distinguish them, on the one hand, from the Hydrozoa, including the hydroids, hydromedusae, and, on the other, from the Siphonophorae. This view, which is confirmed by Miss Hyde, is antagonized by Glaus, and has given rise to a prolonged controversy. The parties to this dispute are practically in accord in regard to the facts of observation, as represented by the figures in their latest contributions. It is in the interpretation of these facts that they differ nuiinly. Glaus ('90) admits that there is an ectodermal invagination previous to the formation of the mouth, and tliat the lining of the proboscis is ectodermal. He maintains, however, that the condition I'epresented in Figs. B, C, and D, is due to a severe contraction of the animal, and is without morphological significance. He denies that there is any oesophagus, " Taschenvorhang," or " Schlundpforte," in the sense that Goette uses these terms ; and with these he rejects the idea of a close affinity between the Anthozoa and scyphomedusae, with the correspondingly sharp distinction between the latter and the hydromedusae. He admits, however, that a distinction of importance between scyphis- toma and hydropolyp is to be found in the possession by the former of an ectodermal lining of the proboscis, and in the presence of gastric pouches and septa. Goette's position has been strengthened considerably by his latest contribution on this subject ('93) , and his conclusions are confirmed in nearly every particular by Miss Hyde. Goette's figures appear to be camera drawings of serial sections, and are a great improvement over the rather diagrammatic illustrations in his earlier papers. They are not entirely convincing, however, for the ectoderm and the endoderm grade into each other so that it is impossible to determine the exact boundary ; and the material is so subject to distortion during the preservation that it is often difficult to determine whether a given fold of the epithelium is of morphological value or is merely an artifact. Miss Hyde fails to confirm the view that the whole of the second pair of gastric 212 ROBERT PAYNE BIGELOW ON pouches (and hence, according to Goette, five eighths of tlie peripheral digestive tract of the medusa) is of ectodermal origin. On page 550 of her paper she speaks of only the roof, i. e., the lining of the oral side, of these pouches as formed from oesophageal ecto- derm, and her sections bear out this view. The foregoing brief siimmary of the present state of knowledge regarding the early stages in the development of the sexually produced scyphistoma will serve as an introduction to what is to follow. Mention of the work of others upon the later stages will be made when we come to the corresponding periods in the development of Cassiopea xamachana. The Formation of the Bud. — In 1841 Sars described the budding of scyphistomas that were supjiosed to belong to a species of either AureUa or Cyanea. The buds, accord- ing to this account, may grow out directly from the main part of the body of the larva, or they may be produced on stolons extending outward from the foot. In either case, several buds may be formed, apparently in various positions on the scyphistoma at one time. The figures show the buds attached to the parent and provided with a well- developed crown of tentacles at the distal end. Agassiz ('60) found a similar process of budding to occur occasionally in Avu-elia. Goette ('87) has confirmed these observations, and has found that the larvae of Coti/Iorhiza tuherculata also produce buds. In Cotylorhiza the bvid is formed as an outgrowth from the body of the scyphistoma ; and as it grows it gradually approaches the shape of its parent, but its relative position is just the reverse of what Sars found ; for the distal end forms the stem, and the proximal end begins to flatten out into a circumoral disc. In this condition the bud is set free, and swims about, rotating on its long axis, with its distal end forward. The mouth is formed at the point w^here the constriction finally separates the bud from its parent, and the larva fixes itself by the opposite end. Glaus ('92) has found that the scyphistomas of Cotylorhiza not only produce buds, but that they produce them in large numbers. Scyphistomas reared from eggs that had been laid in September, 1890, were kept alive in the aquaria at Trieste and Vienna throughout the following winter and spring. No change was observed after the larvae had reached the sixteen-tentacle stage, until the following July, when budding occurred. The process was not restricted to a few well-nourished individuals, but seemed to be a gen- eral and repeated phenomenon, and it resulted in a large increase in the number of larvae. Claus's brief description of the formation and fate of the bud, accompanied by three figures, corresponds perfectly with what I have to describe in the following 2)ages. The strobilization, he says, took place in August, and was monodiscous. Another case of rapid multiplication of scyphistomas by budding is described by Lacaze-Duthiers ('93) . A colony of these larvae, of unknown origin, was discovered in CASSIOPEA XAMACHANA. 213 an aquarium at Banyuls in 1892. No strobila or ephyra was observed up to October, 1893j but in the meantime the number of scyphistomas had increased enormously. The buds appeared as elevations on the side of large individuals. The base of this elevation became elongated into a filamentous stolon carrying the bud at its tip. The bud fixed itself to the glass, gradually developed tentacles, and finally became inde25endent by the disappearance of the stolon. In Cassiopea xamachaiia the process of budding is an important, if not the chief, factor in the perpetuation of the species. On looking over collections of scyphistomas taken from the Great Salt Pond during May, June, and July, a considerable number was found with buds attached in various stages of development (Figs. 1, 2, and 26), and budding continued in the aquaria. There is no stolon. The first visible rudiment of the bud is a slio-ht swelling; on one side of the calyx just above where it tapers into the stem. It involves all three layers of the bod}' wall (Fig. 36) . At an early stage in the growth of the bud the four septal muscles may be found as four slender cords of cells embedded in the mesogloea and appar- ently growing out from a thickened area of the ectoderm at the apex of the bud (.s;/;. Figs. 38 and 39). This appearance seems to indicate that the septal muscles of the Imd are formed, as in sexually produced scyphistomas, by an ingrowth of the ectoderm. Careful study of serial sections through young buds shows, howevei', that the septal muscles of the bud are connected with septal muscles of the parent. In Fig. 37 the course of the septal muscles is reconsti-ucted from a sei'ies of longi- tudinal sections. The muscle sriii passes around the base of the bud on the side away from the observer and gives rise to two branches, sm\ and sm'^j. These extend toward the apex of the bud, and each one divides dichotymously. Muscle svi^ gives off a branch which fuses with snii, at the base of the bud. Sm^ produces three branches which unite into a single branch. This branch extends into the base of the bud, but it was impossible to trace it further. It may be connected, pei-haps, with the muscle ^in'.,, which was traced for a short distance from the apex of the bud. On account of the presence of the muscles, it is possible to study the relation of the plan of symmetry of even young buds with the symmetry of the parent. A series of sections made at right angles to the long axis of the bud shows that the vertical perradii of the bud lie in the plane of one of the perradii of the parent. But in transverse sections it is impossible to trace the muscles of the bud, except for short distances, owing to their extreme fineness.* However, the study of longitudinal sections makes it reasonably certain that the sei> ' The position of tlie bud is always pen-atlial, altliougli in some preparations it apjx-ars to be interradial, owing to the obliquity of the sections, its in Fig. 3G, 214 ROBERT PAYNE BIGELOW ON tal muscles of the bud are derived from outgrowths of one or both of the septal muscles of the parent which lie in the interradii adjoining the perradial area of bud formation. If tliis be true, then every part of the young bud is formed from the corresponding j^art of the parent, viz., — ectoderm from ectoderm, mesogloea from mesogloea, endoderm from endo- derm, muscles from muscles, and digestive tract from digestive tract. There is no indica- tion of any method of budding of the kind described by Lang ('92) . In the young bud the mesogloea is very thin, so that the ectoderm and endoderm are very nearly in contact. The evagination gradually increases in size, becoming first hemi- spherical and then more elongated. At the same time a constriction appears close to the body of the scyphistoma, which deepens until the bud becomes a spindle-shaped body attached to its parent by a short and narrow stem consisting of a film of mesogloea covered with ectoderm, the digestive cavity of the bud being entirely closed (Fig. 1) . Scyphistomas are never found with more than two btids attached. When two buds are present they are always of different ages, and the elder is always attached to the apex of the younger (Fig. 2) . llic Planula-like Larva. — When finally constricted off, the bud is a simple, spindle- shaped, hollow body, without trace of mouth or tentacles. It is like a planula in form and habits. The whole surface is covered with cilia, and it swims about, rotating from right to left upon its long axis. In swimming, the distal end is directed forward. While swim- ming, the larva is constantly changing its shape, assuming in a few minutes various forms from an elongated spindle to a short heart-shape (Fig. 3, ^4, B and C) . It swims near the bottom, hiding under any object that it may find there. When it strikes an obstacle, it may rest there quietly, or it may rotate slowly upon its long axis. In all its movements it reminds one very strongly of Agassiz's description of the planulae of Aurelia. The larva is white, sj^eckled with a few greenish l)rown spots. It is rather opaqvxe, but much of the structure may be seen in a living specimen. A longitudinal section shows that the ectoderm consists of a deep layer of very narrow and closely-packed columnar cells (Fig. 39) . The mesogloea contains a few green cells (producing the greenish brown spots) , and some widely scattered coUoblasts. The layer is thickest at the equator, diminishing gradually to a very thin layer at both ends. The four septal muscles [sni) are seen clearly at the distal end of the larva, embedded in the mesogloea and united with the ectoderm near the apex (Fig. 38). In one specimen, not yet detached from the parent, it was possible to trace one of the muscles all the way from the proximal to the distal end. The muscle fibres are already differentiated and line the tube of mesogloea, while the nuclei occupy a central position. The endoderm is a columnar epithelium, rather thin, with the cells closely packed CASSIOPEA XAMACHANA. 215 together and coarsely granular at the proxhnal or posterior end of the larva. Toward the equator the cells become higher ; and at the distal, or anterior, end they are large and clear. The character of the endoderni makes it possible to identify the anterior end of the swimming larva with the distal end of the bud. The Formation of the Mouth. — The first change to be seen in the swimming larva is the formation of the mouth, which occurs two or three days after the larva has been set free. When writing my preliminary paper ('92 a) , I was in doubt as to the relation between the poles of the bud and tliose of the larva. The better and more abundant material obtained during the second visit to Jamaica proved conclusively that the proxi- mal end of the bud forms the oral end of the larva, just as it does in Cotylorhiza, accord- ing to Goette. The identification is made easy by the polar differentiation of the endoderm described in the previous section. When first seen the mouth looks like a minute pin-hole in the posterior end of the larva (m, Fig. 4 B) . In longitudinal sections at this stage the first indication of the for- mation of the mouth is the disappearance of the mesogloea from a small area at the poste- rior end, so that there is no longer a distinct boundary there between the ectoderm and endoderm [m, Fig. 40) . At the same time a small dent appears in the outer surface. This deepens until it forms a minute tube connecting the endodermal cavity with the exterior (Fig. 41). The mouth thus formed gradually widens and becomes slightly funnel-shaped. Further stages in the-development of the mouth are represented in Figs. 5, 6, 7. In In Fig. 6 there is a distinct circular groove which outlines the base of the proboscis and separates it from a rudimentary peristome. In Fig. 7 the peristome is well developed, and the mouth is widely open. There is no invagination of the ectoderm connected with the formation of the mouth, aiid there is no oesophagus, " Schhnidpforte " or '' Taschenvorhang." So, if Goette's account of the formation of the mouth in the sexually produced scyphistomas be accepted, we have here a case where an agamogenetic differs to a marked degree from the gamogenetic course of development. 21ie Sfyp]usto)ita. — With the elongation of the forward end, the formation of ten- tacles, aird the development of four gasti'ic pouches, the free-swimming larva Ijecomes a typical scyphistoma. By the end of the third or fourth day after the bud has been set free, the forward end of the larva has elongated to form a stem equal in length to tlie rest of the body (Figs. 7, 8, '.), and 11). The end of the stem becomes expanded, generally flattened, and the epithelium covering it becomes deeper than the rest (Fig. 42) . This epithelium pro- duces a secretion which serves to fasten the larva to some solid object. Fixation usually takes place during the fourth or fifth day, but the tinie varies greatly. 21G ROBERT PAYNE BIGELOW ON Development of the Tentacles. — During the third day the peristome appears as a minute ridge surrounding the posterior end of the hirv^a, a short distance from the mouth. The first series of tentacles arises during the following twentj'-four hours as four perradial angles in the margin of the peristome (Fig. 8) . Four interradial tentacles appear almost simultaneously with these, or sometimes considerably later (Figs. 9, 10, 11, and 12). The elongation of the tentacles takes place rapidly, so that at about the end of the sixth day the peristome is surmounted by a crown of eight tentacles, whicli equal the jiroboscis in length. With the broadening of the peristome the differentiation of the body of the scyphis- toma into stem and calyx becomes apparent externally (Figs. 1.3 and 14). When the eight perradial and interradial tentacles have become long enough to reach some distance beyond the mouth, eight adradial tentacles appear in the angles between them. In Fig. 14 the adradial tentacles are distinctly developed, and two of the tentacles of the first series are bifurcated near the base. Figs. 15 and 16 represent the tyjjical scyphistoma in the sixteen-tentacle stage. The tentacles are now long and graceful, and thickly dotted with batteries of nettle cells. When fully developed, the scyphistoma is about one millimeter and a half in diameter ; and it is provided typically with thirty-two tentacles.^ But there is as much variation in the number of tentacles in the scyphistoma as there is in the number of sense organs and parameres in the adult. The number of tentacles is seldom less than thirty-two, often greater. The way in which this variation takes place is indicated in Figs. 21 and 14. All degrees of anomaly maybe observed, from a bifurcated tentacle shown at x in Fig. 21, through the condition represented in Fig. 14, to two completely separated tentacles occu- pying the position of one typical one. The tentacles of a well-developed scyphistoma, when fully expanded, exceed the length of the body several times. Accoi-ding to the position in which they are held, the tentacles may be divided into two series. Those of one series are held nearly erect, while those of the other series, consisting of the alternate tentacles, are bent backward until their tips nearly touch the ground vipon whicli the animal rests. The action of the ten- tacles in capturing prey may be observed in a small aquarium, under the microscope. As soon as a tentacle comes into contact with a small floating body, such as a copepod, it is whipped quickly into the mouth, and at the same instant the side of the mouth toward the tentacle is opened more widely. On one occasion I saw two tentacles make captures at the same time, and the mouth expanded in both directions at once, showing a close co-ordination between the movements of the tentacles and of the mouth. ' Specimens have been foiind witli twenty-four tentacles, but it is uncertain wliether tliis is a regular stage in develop- ment between the sixteen- and thirty-two-tentacle stage, or a duplication of tentacles of the eai-lier stage. CASSIOPEA XAMACHANA. 217 Development of the Gastric Pouches. — While the final result is the same, the method of development of the gastric i^ouches differs entirely in our larva from the process as described by Goette. The free-swimming larva is somewhat flattened laterally (Fig. 4) , and the long and short diameters are in the planes of the perradii. But there is no evidence that the gastric pouches in the long diameter are formed any earlier than those in the short diameter, and the ectoderm plays no part in their development. The formation of the gastric pouches is usually described as a process of evagination; but in this case, at least in the earliest stages, the delineation of the pouches seems to be due rather to the ingrowth of the septa. These appear at the time of the formation of the first tentacles (Fig. 8) as four minute vertical folds of the endoderm (sejj, Fig. 43) , placed equidistantly in the angle formed by the peristomal fold (compare Fig. 42) . Tlie mesogloeal portion of the septum is at first very thin, and in the four-tentacle stage (Figs. 8 and 4-3) is no higher than the thickness of the endodermal layer of cells. The septal muscles do not penetrate the septa at this stage. While well-developed below, they can be traced ujiward only to within 35 or 41 /i,^ from the l;)ase of the septa. In the eight-tentacle stage (Fig. 13) the septum is still very small, and the septal mesogloea near the margin of the peristome is very thin, hardly thicker than a cell wall. But at the central margin it has increased in thickness, and now the septal muscle may be traced from the stem upward through this thickened portion of the septal mesogloea to the peristomal ectoderm (s7n, Figs. 44 and 47). It is impossible to determine whether the new portion of the septal muscles is formed by growth upward of the muscles already present in the stem, or whether it is the result of a proliferation of the peristomal ecto- derm which may grow downward and fuse with the older portion of the septal muscles. The four septa are now complete, and divide the digestive cavity into a large central stomach, extending into the stem, and four shallow marginal gastric pouches. The gastric jDouches expand with the growth of the peristomal disc, so that the ecto- derm and endoderm remain in close contact at the margin ; while the central edges of the septa retain their original relative position. Thus the gastric pouches and the septa become deeper as the larva increases in size. This is evident in the sixteen-tentacle stage (Figs. 15 and 45 to 49) . It will be shown later that the relation of the interradial ten- tacles to the septa is variable. In this stage, however, the distal part of the septal meso- gloea has begun to disappear, so that immediately under the interradial tentacles the endoderm of adjacent pouches is fused (Figs. 45, 4G, and 47). In the fully developed scyphistoma this area of fusion is perforated, so that there is a communication between adjacent pouches, forming the " Ringsinus " of German authoi's. In the specimen with ' 35 or 41 |i = aljuut oiif seventh of the h-ngth of the larva. 218 ROBERT PAYNE BIGELOW ON forty-two tentacles, from which the section represented in Fig. 51 was taken, this per- foration was very small. Figs. 52 and 5o rej^resent a little later stage, in wliicli the opening has become much wider. Each septal muscle is a solid cord of cells, with a single layer of longitudinal muscle fibres in its periphery. In the peristome. the fibres of the septal muscles .sjiread out in a fan-shaped arrangement toward the margin. Four slight interradial depressions in tlie peristome mny be observed as early as the four-tentacle stage. They are deeper in the eight- and sixteen-tentacle stages, and the septal muscles may be seen to join the ectoderm at their bottoms. These depressions may be homologous with the septal funnels of the Stauromedusae, or they may be merely the result of the contracted condition of the larva. The question is of no importance, for there can be no douljt about tlie homology of the nuiscles ; and whether they are solid or hollow is merely a matter of detail. In later stages (Figs. 51 and 52) sections seem to show that the peristomal depressions have deepened centrally so as to leave the inser- tion of the septal muscles high up on the peripheral side. But here, again, before any morphological conclusions can be drawni, account must be taken of the growth of the perradial angles of the proboscis and of the effect of the contraction of the septal and peristomal muscles. Relation of Sejjta to Literradial Tentacles. — According to Goette, the interradial tentacles are always interseptal in origin. Tliat is, two of these tentacles are produced as diverticulae from each of the second pair of gastric pouches (ectodermal) , and their subse- quent position in the planes of the septa is due to a secondary shifting. He finds in this important evidence in favor of his theory of the close affinity between the Scyphomedusae and the Anthozoa, for the tentacles of the latter are also invariably inter- septal. Claus, on the other hand, finds that the interradial tentacles of Anrelia and Coty- lorhiza are variable in origin. According to his observations ('91 and '92), an interradial tentacle ma}' be interseptal, that is, arise as a diverticulum of a single gastric poucli, the endoderm growing out and pushing the ectoderm before it ; or it may arise in the plane of a septum by the union of two endodermal diverticulae, one from each of the adjacent pouches. He holds, therefore, that the origin of the tentacles cannot be used as evidence to upliold Goette's theory. My observations on Cassiopea are in perfect accord with those of Claus. A number of series of transverse serial sections made from young scypliistomas in the eight- and sixteen-tentacle stages were studied carefully with the aid of camera sketches drawn on transparent paper. By this means the relations of the parts could be determined accu- rately; and the results are embodied in the series of diagrams, Figs. H to L. In the eight-tentacle stage, according to Goette, the gastric pouches in the long diameter, ;• /•, CASSrOPEA XAMACHANA. 210 should each give rise to a single tentacle, while the pouches in the short diameter, r' r', should each produce three. From a glance at Figs. H and J it will lie seen that this is not the case in Cassiopea. To be sure, most of the tentacles ^^ W I "^ this stage are interseptal in position, but the interradial ten- tacles arise as often from pouch- es in the long diameter, r r, as from those in the short diame- ter, / r' ; and in both Figs. H and I there is one interradial tentacle that is distinctly septal in position. The septa are still complete, so that tliei'e can hardly be any chance of a shift- ing of position. In the sixteen- tentacle stage, there is a ten- tacle in the plane of each septum (Figs. K and L) ; but here the perforation of the septa has commenced, and a shifting of relative position is possible. Even at this stage irregularities are common. For example, one of the septa in Fig. K is placed asymmetrically with relation to the tentacles, and two tentacles are wanting in Fig. L. The Stroh'da, — Dei^elopvient of the lihopaVui. — When the scyphistoma has reached a diameter of about two millimeters, there appear the first characters that are distinctive of the strobihi. The first noticeable change in this direction takes place at the bases of the tentacles of the more erect series. This change may be regarded either as the outgrowth of a conical lobe from the margin of the circumoral disc bearing the tentacle at its tip, or as a conical widening of the basal portion of the tentacle. The former view is probably the better. At about this time there appear in the tentacle, just beyond the apex of the cone from which it springs, a few glistening white bodies. These ai"e the so-called otoliths, and mark the beginning of the formation of the rhopalium (Figs. 17 and 18). The tentacles containing these will be called the rhopalial tentacles. These concretions, or otoliths, increase in number until they form a conspic- uous mass, while the basal cone begins to broaden laterally. This is now distinctly non- Figs. H-L. I)i,igrams illustrating the spaoe relations between the septa and the tentacles, observed in five young scyphistomas of C'ass/opea Xdina- chana. r — radii of tlie long diameter, r' — riulii of the short diameter. 220 ROBERT PAYNE BIOELOW ON contractile, and may l)e spoken of as a marginal lobe of the peristome (Figs. 19 and 20). In the specimen shown in Fig. 21 we see the first indication of strobilization. The upper, expanded part of the calyx is separated from a conical, lower portion by a slight groove. The marginal lobes have become semicircular in outline, and a slight elevation is noticeable on the aboral side of each rhopalial tentacle immediately external to the mass of concretions. The epithelium at this point is pigmented, and forms the first rudiment of the eye {oc. Fig. 22) . Fig. 2-3 illustrates a more advanced stage, where the proximal part of the tentacle is beginning to take on its final shape, and is separated by a pro- nounced bend from the distal portion, which is still functional as a tentacle. We come finally to a stage in which, while the long distal part of the tentacle i^etains its chai'acterisdc structure and remains completely functional, the short proximal part has become comj^letely differentiated into a rhopalium. Fig. 54 is from a longitudinal section of such a tentacle. The rhopalial part has assumed nearly its final shape. The differentiation of its ectoderm into sensory epithelium, eye-spot, and layer of nerve fibres, is complete. It has a lumen that extends outward to the solid chorda-like endoderm of the distal part of the tentacle, and opens toward the centre into a gastric pocket. The endo- dermal hning of the lumen is a columnar epithelium, the more distal cells being deeper and containing the concretions. Compare Fig. 54 with Fig. 53, which, being interradial, was certainly destined to be a rhopalial tentacle. The growth of the marginal lobes, which were semicircular at the stage of Fig. 21, has continued, and each lobe has now produced two secondary ones, one on each side of the rhopalial tentacle. These are connected by a slight ridge that crosses the base of the tentacle on its al)oral side {h. Fig. 54). The secondary lobes are the rhopalial lobes of the margin of the umbrella (Flligellappen of German authors), and the connecting ridge is the hood (Deckplatte) that covers the rhopalium. These marginal structures may be seen in Fig. 24, and this brings us to another stage in the development of the rhopalium, the absorption of the distal part of the tentacle. In the strobila shown in Fig. 24, the rhopalial tentacles have a very different appearance from what we have seen before. They are shorter than the other tentacles, and are much swollen at a point just beyond the eye-spot. The distal portion is begin- ning to degenerate. Tliis process, when once begun, proceeds rapidly. During the few hours that were spent in making this drawing, the rhopalial tentacles were reduced in length nearly one half. The eye-spots and concretions were conspicuous, and in each of the former there was a slight cup-shaped depression. This is the earliest stage in which I observed slight medusa-like movements of the ephyra disc. The tentacle at this stage is in a process of degeneration for about fifteen hundredths of a millimeter outward from the ocellus. In this area of degeneration ( t. Fig. 55) the endodermal cells are broken down, CASSIOPEA XAMACHANA. 221 the supporting membrane has disappeared, and the inner boundary of the ectoderm is indistinct. The axial mass of this part of the tentacle is made up of loose particles of a finely granular sul)stance, in which may be seen many small and deeply stained nuclei.- There are also a number of green cells that apparently escaped into the central mass when the supporting membrane broke down. There is evidently a free communication between this mass of disintegi'ating material and the digestive cavity, through the rliopalial canal. The method by which the shortening of the tentacle is brought about would seem to be as follows: The axial cells adjoining the cells that bear the concretions (Fig. 54) first break down. Why they should do so, and at this particular time, 1 cannot say. This disintegration proceeds centrifugally, and it is accompanied by a dissolution of the sup- porting membrane. The ectodermal cells then either begin here and there to break down while still in place, and the resulting debris is squeezed into the central cavity; or else, the cells migrate, or are squeezed inward and then disintegrate. The continuity of the remaining ectoderm is maintained, however. The products of degeneration prob- ably pass through the rhopalial canal into the digestive tract. As this process continues, the inward movement of the ectodermal cells is more rapid than their disintegration, so that when the distal jjart of the tentacle is reduced to the size of the rhopalial part (Figs. 25 and 55), it is a solid mass of small cells with small nuclei that stain dark. Some of these cells contain a large vacuole and have the nucleus pushed to one side. Scattered among the small cells, there are a number of globidar bodies as large as, or larger than, the green cells, and completely filled with coarse granules that stain deeply with safranin; no nucleus is visible in them. The ocellus has now become distinctly cup-shaped (oc. Fig. 55). At about this time the interrhopalial tentacles begin to be absorbed in their turn (Fig. 25) . The umbrellar margin has in the mean time grown out beyond the insertion of each interrhopalial tentacle, on its aboral side, into two lobes with a hood between (Figs. 25 and 26). T'lis structure, although smaller, corresponds exactly to the rhoiDalial lobes and hood, and is further evidence for the homology between the tentacles and the rhopalia. The drawing reproduced in Fig. 25 was made between the hours of eleven in the morning and two in the afternoon. At five o'clock of the same day the tentacles had been reduced to one third the length shown in the figure, and the absorption of the rliopalial tentacles was very nearly completed. In the later stages of the absorption of the interrhopalial tentacles, the broken-down material is evidently forced in some way into the radial canal. The rhopalium (Fig. 56) is practically complete at this stage. The point (x) where the last trace of the tentacle proper disappeared, is still distinguishable in sections by the presence of small cells with indistinct cell walls, and by the absence of otoliths. 222 ROBERT PAYNE BIGELOW ON These observations, then, confirni those of Claus ('83,) who, without going into the details ot" development, maintained that the rhopalia are modified basal portions of the tentacles of the scyphistoma; and they contradict Goette's statement that the rhopalia are developed independently of the tentacles. Other Phenomena of Strobilization. — While the marginal structures are undergoing the metamorphosis that has just been described, important alterations are taking place in the general shape of the body. The horizontal constriction first noticed in Fig. 21 has deepened (Fig. 24), while the fold below it has heightened, and the upper portion has broad- ened and flattened, until the condition shown in Fig. 26 is reached. At this final stage the upper portion has all the characteristics of a free-swiniraing medusa (ephyrula), except that it is attached by a slender aboral stem to the centre of a goblet-shajjed basal polyp. The four interradial depressions in the peristome of the earlier stages have become nearly flattened out, all that remains of them being the hollows between the projecting radial angles, or pillars, of the proboscis, which have now become very prominent. At the stage of Fig. 21, there may be noticed on the proboscis eight patches of thickened ectoderm containing many nettle cells. These nettle batteries are arranged symmetrically, one on each side of each pillar of the proboscis. At a little later stage (Fig. 24) the batteries have become invaginated, forming cup-shaped depressions, thickly crowded with nettle cells in all stages of development. During the time when the larva is being differentiated externally into an upper and a lower portion, internal changes are taking place in the former, which result in the disappearance of structures characteristic of the scyphistoma and the appearance of others distinctive of the medusa. The orifices in the gastric septa have become relatively larger (c.s. Fig. 52 and re. Fig- 57) until the septa are reduced to columnar pillars, columellae, connecting the upper and lower walls of the body and pierced longitudinally by the septal muscles (c. Fig. 58) . The columellae are called by German authors "Septalknoteu," but they are not homologous with the so-called " Septalknoten," or areas of adhesion, in the Peromedusae. The columellae of the Peromedusae are the walls of the large septal funnels where they pass from the subumbrella to the exumbrella, and, according to Haeckel's figures, are separated by the gonads from the areas of adhesion. In the fully developed scyphistoma of Cassiopea, the septal muscles are solid throughout their length, and there is no cavity corresponding to the septal funnels, which, according to Goette, are well developed in Aurelia. But in' the strobila there does appear a slight depression extending a very short distance into the end of each septal muscle. In Figs. 57 and 58, where this is well marked, much of the depression may be due to the strongly contracted condition of the specimens; but other specimens CASSIOPEA XAMACHxVNA. 223 not so contracted show at lei^t tlie deeper part of the cavity, whieli theret'on*, nmy be truly a vestige of the septal funnel. At an early stage of strohilization there may be noticed a sliort conical projection from the central edge of each coluniellii. It extends also around the sides. These pro- jections are pri>bal)ly the rudinuMits of the first four gastric (ilanients, which are dis- tinctly developed at liie time wiicn the ephyrida is set fi'ce (j//, Fig. -58). While the sept:i are shiinkiiig to Itecome tiie coUiinellae, ridges appear opposite eacli otiier on the upper ami lower wails of the peripheral part of the digestive tract between the bases of the tentacles. The epithelial membranes at the summits of op[)0- site ridges unite, and thus there is formed a series of lines of adhesion extending inward from the jieriphery and dividing the sjjace into a series of radial canals, each ending in a tentacle. Tlie two discs of mesogloea never fuse along these lines of adhesion, but the endoderm remains lietween them as the endodermal lamella, or cathanimal plate. At the stage of Fig. 2i the lines of adhesiim occupy abcnit half the space from the margin to the cohuncllae. The lower disc ol I he slrobila ri'nuiins simply an a,niiular fold of the body wall ind.il the metamor[)Iiosis of the upper disc is nearly complete. The se[ital muscles in this region bend outward with the rest of the body wall (Fig. 57) . At length, however, the endoderm grows out toward the periphery as four shallow pouches, leaving septa, between them which contain the longitudinal muscles. Very soon after this the septa are perforated so as to allow a fusion of the endoderm at their upper angles (Fig. 58). In the last stage of strohilization (Figs. 2li and O'J) the longitmlinal muscles may be traced from the peristome thronnh the columellae and the mesoycloea. of the exumbrella. to the narrow isthmus wluue the ephyrula disc joins the basal [)olyp. The latter has now a well- deseloped peristome (Fig. -VJ), and the mesogloea iu this region is very thin. Just in tlie istlnnus the muscles have ilisap[ieared, but. they may be found again in the [)eristome of the basal polyp and traced for a distance close under the epithelium to tlie edges of the se[>ta, where they lieud abruptly downwaid, and continue through the septa, into the stem. Altlnnigh seldom \isible in the living specimen, sections sIkjw that tlie basal polyp at this stage possesses eight short tenacles (Fig. 5!)). It has al.so an annular fold of the ectoderm, closely surrounding the isthmus (Fig. 51) and^/. Fig. 611). This fold is the rudiment of a new [iroboscis, which is without doubt, entirely ectodermal in origin. But, as Goette has pointed out, it does not follow from this that the lining of the [iroboscis is ectodermal in scy|ihislomas developed from the egg. Pulsating contractions of the umbrella, are lirst noticed at the time when the rhopalial tentacles begin to be ab.sorbed (Fig. 21). They are then feeble and at long intervals. At the stage of Fig- 2G these 224 ROBERT PAYNE lilGELoW ON movements arc rapiil .nid violent. The rliytlini is iiitenn|iteil liy few pauses, and tliese are short. The result nl' these movements is tliat the thin wall of the isthmus is ruptureil, and the ephyrula is set free. AftiT tins separation, the basal polyp has the ap[)eaiancc i-e|iresented in Figs. Ii7 and 28. It is a scyphistunni with seventeen short tentacles and a rudimentary proboscis (Figs. (Jl and 62). The proboscis and the tentacles grow rapidly, so that in a few days it is inijiossible to distinguish a regenerated basal polyp from a young scy|)histoma in the sixteen-tentacle stage, except that the former has a souiewhat thicker stem. It nniy be inferred from this complete regeneration of the basal polyp that it undergoes repeated strobilization, as Clans' has found to be the case in x\urelia. The Ephyruld. — The ephyrulaof Cassio|iea is very different in appearance from the corresponding stage in ordinary scj'phomednsae with eight rhopalia. Cotylorhiza has an ephyrula rescMubling the same stage in tlu! senmstonuitous medusae. Good figures of this are given by du Plessis and Clans, and there is a striking difference between these figures and Figs. 29 and oO in this paper, which are camera drawings of well-preserved ephyrulas of Cassiopea, mounted in balsam. Fig. 2U rejiresents a young Cassiopea tiiat has not long enjoyed a free existence. The general shape of the undirella is like that of the adult, and there is the same concavity in the centre of the exumbrella, while the margin curves in the opposite direction, as in Fig. 64. The typical eph3a-ula of Aurelia or Cotylorhiza has eight marginal arms with two lobes at the end of each, and between each pair of lobes there is a rhopalium. In Ca.ssiopea. structures coi'responding to these arms are present to the number of sixteen, or often more. But these do not destroy the general circular outline of the animal, for they are connected by thin areas on the undjrella, alternating with an e(|ual number of ridges, which at an earlier stage bore the interrhopalial tentacles on their under sides. We have, then, at this stage the marginal zone of the umbrella marked by a number of short radial ridges separated by an equal number of thin areas. The ridges are in line with the radial canals. At the peripheral end of each ridge the margin of the umbrella is produced into two lobes, those adioiiiing the rhojialia being well marked, the others small and inconspicuous (il. Fig. 30). In Fig. 21) there are seventeen, and in Fig. 30, twenty-three, rhopalia. The latter is an unusually large number, an; which there is a, groove that is continuous witli ll ther two gi'ooves, and that extends into the stomach. On the interradial side of each of the eight labial grooves, there mav be sei'u a small roughly circular area that is less transparent than the rest. These areas are the nettle batteries, first seen in the strobila. The margins of the lips are provided with numerous small jirocesses, tlie digitella, which are arranged in a single continuous series. Fig. (3o is a, section of an e])liyrnhi that has just become free. In this stage there is still an opening through the aboral wall of the stomach, and one may see the last vestige of the connection between the columella and the exumbrella, which contains also the degenerating remnants of the septal muscle. At a little later stage, when the opening in the roof of the stomach has closed, both the septal muscles and the septal funnels totally disappear. Sometimes one, some- times the other, is the first to vanisli. The Later Stages. — The later stages in the development of Cassiopea will be treated very briefly. Wiiile the umbrella I'cmains at first unchanged, the metamor- phosis of the month parts is inaugurated by the growth of the two outer angles of each of the more or less quadrate lips, so that they jire soon drawn out into extended lobes (Fig. 31). At the same time the jjillars of the proboscis thicken, and the mesogloea is continued outward ;dong each of these lobes as a midrib. We have then eiglit oral arms, each with a, longitudinal groove, supported by a midrib, and fringed with digi- tella,— arms very similar to those characteristic of the genus Aurosa Haeckel ('79). But it is only the mouth ]>arts of Cassiopea that may be said to pass through an Aurosa stage, for the comparison cannot, at this time at least, be carried to the other organs. Clans has described (83) some of the principal stages in the metamorphosis of Pilema (Rhizostoma) and Cotylorliiza. He regards the formation of the eight oral arms as a dif- ferent process in these forms from what occurs in Aurosa. But it appears to be merely the same thing expressed differently. In the next stage we find two oral iinniels, oi- oscida. and a small vesicle developed at the tip of each oral arm. The othei- p(ntions of the arm are still open and fringed with digitella, as before, but the outline is no longer a regular ein\e, for there are folds iji the 22C> T;r)i'.F.r>T I'ayne r.rcKLow ox niJirjfiii. 'I'll*' deepest lolils mi'c the most dist.-il. iiikI lliev liecoine [iroH-ressively more slialliiw towMi'il tli<' liase of the arm. The central month is still widelv open. The snhu'eni- tal eaxilies aic well developed at this stage. Fiii's. ()4, (iO, and (Ki show liow the oral disc is lorme(l, and how the snhgenilal cavities are prodneed li\ the great increase in tiiickiies.s of the mesouloea at the pillars of the pi'ohoscis and the liases of the oral arms. l?y the o'vowtli of these strnetnres. the snliu'eiiital caNilies are necessai'ih' iirodnced. The oid\' Special adaptations are the subsequent growth and folding of the ahoral wall and the narrowing of the orifice. The marginal lohes of the mnhrcdla now hegin to hi'oaden. and thns approach the adnlt condition. Imt there is (ndy a single " \'ellar " lohe between two rIio]ialial ones. At a little later stage, when there ai'e three oral iinmels at the tips of the arms (Fig. 33), the re-enti-ant angles between the pillars of the proiioscis have grown inward, met at the centre, and fnsed. Tn this way the bnni'n of the oesophagns is divided into fonr tnbes (Fig. ^l'.!). representing the grooves that were present in its angles in the earlier stages. in the lignre the fusion at the centre has g(>n<> so far as to invoh'e the edges of the lips, ami the labial grooves of the dil'fei-ent pairs of arms ait- not in o])en commnnication. but a short cross-shaped tube connects them at the centre, and the oral disc is now com[ilcted. It is interesting to note that Clans has found a stage both in I'ilema and in Coty- hu'lii/.a that, while showing the cliaracteristic fannly difierences, has also a certain resemblance to this stage in Oassiopea. In all three the walls t\\' the proboscis have fnsed so as to di\ide its lunu'u into four tnbes, and the formation of oscnla has lieguu at the tips of the arms in snch a way that we have on each arm three oscula with a vesicle in the ano-les between them. The occin-rence of this staux- in the ontooenv of three so dislin<-llv separated families must have some morphological signiiicaiK-e. ami we niay regard these eight primal}' xi'sicles as homologous in the three gron[is. The mode of formation of the oral funnels hecomes (>\ident at this stage. They are not fornieil in (Jassiopea simply by a series of fusions of the lips along the line ol the lal)ial groove, as llamann (81) states to be the casein Cotylorhi/.a. It is more like the process in Pilema, as described b\- Clans. Each of the piimary funnels is represented at lirst by one of the folds in the mai'giu of the lips referred to above (F'ig. 33) . The folil di'e|iens. and its edges are brought together on the \cntral side and fuse. lea\iug an o|iening at the a,])e.x of tlie fold, the osculum. At the same time the lal)ia,l groove in this region is converted into a canal b\- the fusion of the lips on its two sides. After the fusion all trace of what has occurred (piickly disappears. With the division of the oesophagus into four tubes, and the completion ol the oral disc, our larva comes to be distinctly a rhizostoniatous medu.sa. Further development of CASSIOPEA XAMACHANA. 227 tlu' moiitli |);irts consists in the ('mitiniied division of the labial, or l)rachial, grooves into oral fnnnels and brachial canal, together with tlie development of oral vesicles. By the time two or three vesicles have l)een formed on the end of each arm, a vesicle appears in the (tenti'e ol tiie oral disc. Except for tiiis interrnption. tlie development of the mouth parts proceeds regnlarlv in a centripetal direction. The funnels a,nd vesicles are formed first at llic tips of the arms, and then one after anolhei' in regular succession towai'd the centre. Each of these primary funnels is the rudiiiicnt of one of the priniar\' branches of the arm. Whi-ii the ]irocess of forming funnels has I'cached al)ont half tiie length of the arm, the distal funnels begin to snl>(li\i(lc. P>y this subdivision of tlie ])rimary funnels new ones are produced, of wliidi some are the rudiments of secondarv branches ; these sub- divide again, and so on. as long as growlli continues. The subdivision is not dichotomous, liut takes [)lace in such a way as to pro(luce alternate branches. The formation of a vesi(de takes place at this stage in some way at about the time of the completion of the adjoining fnniu'l. I have not been able to ilelernnne whether the vesicle is a funnel with the orifice clost'd, as llamann claims it to be, oi' whether it is an I'vagination from the pedicle of a funnel, as at lirst it st'cmed to nu' to be, and as (Hans thinks it probably is. According to Ha.eckel ('79), the geiuis Archirhiza represents a form that was the ancestor of all the rhi/ostomatous medusae. Of this genus there are two known s|)e(Mes, A. prriiiorditi/is Ilaeckel, and .1. iiiimsti llaeckel. They agree in having foui- subgeuital cavities and eight simple nnbr.niched arms that are provided with a single zig-zag row of closely set oral funnels, and are devoid of other appendages. llamann says that a stage re[iresenting this condition is a featm-e of the ontogeny of rhizostomatous medusae. From Avhat has been said it is evident that we liave no .such stage in the develojmient of Cassi- njtfd xdiiiiii-hdiiii. lor while the labial groo\e is still open in l!i<' jproximal half of tlie oral arm, in its distal li.df the vericles are formed, and brandies are in the process of foi'uialion. The outline of the undirellar maruin has not cluinced esseutialh since tlie last sta^e The areas of adliesion have liecome much wider than the radial canals they separate, and in them there has appeared a network of anastomosing canals, wliile the gastric filaments have become numerous. We have now followed the lai-\;i of our Ca.s.siopea from its lirst appearance as a bud to a point where, with the excei)lioii of the gonads, all the organs of the adult are out- lined. Here we nuist take leave of it. 228 liOliEKT PAYNE BIGELOW ON SUMMAUY AND CONCLUSIONS. Cassiopea iuul Polyciloiiia arc ^'Oiicra ot ilii/.ostoiiiMtoiis mciinsac ])eciiliar]\' inodilicd in adaptation to a sedentary mode of lite in shallow water .hikiuu- the maniiioves honlering ti'opical seas. A c^oinjiarison of specimens of I'dIiii-Iokki /'m/it/osti Au. with Cussiopea xamaclidiiii shows tliat these two forms ai'c specilicMlly distinct, althouuh in general appearance they are very similar and they have the same geographical range and habitat. C. vdhiiii'hditd is remarkable for its variability. This is especially shown in the appendages to the month parts and in the strnctni-cs ,it the margin of the undirella. It will be noticed that the most frequent number of rhopalia, in the twent3--seven .specimens examined, was sixteen, Avhich is the typical number for the genus. But the variations are not arranged symmetrically on the two sides of this mode, for specimens having a greater number of rhopalia are more than twice as many as those having less. The species shows a strong tendency toward duplication of the rhopalia and associated strnc- tvu'es of the umbrella; and at the same time the symmetrical relations of the ])arts tend to be preserved. The great majority of scyphonjednsac have only eight rhopalia. and in Cassiopea with its sixteen rhopalia we have a benutifid illustration of Darwin's law that "Apart developed in any species in an extraordinary ilegree or manner, in comparison with the same part in allied species, tends to be highly variable." Study of the color markings and measurements of the'mouth parts indicntes the divisi(ni of the s])ecies into three varieties; and it was in one of these, var. ^1, that the dn|ilication of marginal organs was especially prevalent. The color of both larvae and adults is due to a grent extent to the ]iresence in the mesogloea of minute symbiotic algae. That these are phint cells was demonstrated by micro-chemical tests. Their presence undoubtedly enables the nieilnsae to live in water that would be too poor in oxygen for most m.irine animals. The search for develo])ing eggs proved nnsuccessfnl. but scyphistoma l.iixae were abundant, and it was found that they were multiplying lapidly by budding. The bud arises as an evagination of the body wall of the scyphistoma. There is no evidence of any special gemminal epitheliiun. The bud. when set free, differs from a planula chiefly in the possession of a well-deiined mesogloea and four septal muscles. The septal muscles are showm to be formed as branches of tlu> two adjacent septal muscles of the parent. The mouth of the young scyphistom;i is birnied by a minute perforMtion at the former point of attachment, while the distal end of the i)ud becomes the stem. This remarkable orientation agrees with what Goette and Cl.ius b.ive found in Cotylorhi/a. In • CASSIOPEA XAJNIACHANA. 229 tho formation of the mouth there is no evidence of any invagination of ectoderm Ap- parently- the oesopliagus, as \vell a.s the gastric pouches, is hned with endoderni. On the other hand, the oesophagus of the lower disc of the strobila is formed wholly of ect(in tlu' other hand, the eight- tentacle stage of the bud lar\a of Cassio|»ea is so like the sauu' stage of the sexually pro- duced larva of its neai' relative I'olyclonia that it would be impossible to tell them a[)art, and, in the absence oi any I'xick'uce to the coulrary. there seems to be no necessary reascju CASSIOPEA XAMACHANA. 231 for supposing tluit their latiT liistory is ditt'erent. At any rate, we have here the first fairly complete liistory of tiie development of a scyphomedusa from the bud; and wlien the sexual development of Cassioj^ea xamachana or an allied species is studied, this memoir will serve as a means of comparison, and will make it possible to determine whether or not the two modes of ontogeny are alike. Literature. Agassiz, A. '65. North American Acalephae. Illnsti-ated catalogue ni the Museum of comp. zool. at llarvanl College. No. 2, ISt)5, p. 41. '81. Polyclouia troiidosa. Nature, vol. 24, 1881, p. 500. Agassiz, A., & Mayer, A. G. "99. Acalephs from the Fiji Islands. Bull. mus. eumii. zool., vol. 32, uo. 9, 1809. (De.scriplion of Crtssto/zeil w/ro.sta.) Agassiz, L. '60. Contributions to tlie natural history of the United States of America. Vols. 3 and 4. Bostiui, 1800. Ai-cher, H. '81. Medusae. Nature, vol. 24, 1881. p. 307. Berger, E. W. 1900. Phy.siology and histology of the Cubomedusae, inrludiujf Dr. F. S. Conant's notes on physiology. Mem. Iiiol. lab. Johns Hopkins Univ. vol. 4, no. 4. Bigelow, U, P. '90. The marginal .seiLse organs in the Pelagidae. Johns Hopkins Univ. circ, vol. 9, 1890, no. ,80, p. 05. '92a. On reproduction by budding in the Discomedusae. J. H. U. circ, vol. 11, 1802, no. 97, p. 71. '92b. On the developmi-nt of the marginal .sen.se organs of a rhizo.stomatous medu.sa. .1. II. U. circ, vol. II, 1S02. no. 97, p. 84. '92c. On a new species of Cassiopea from .lamaica. Zool. Anz., .lahrg. 1-5, 1892, no. 393, jip. 212-214. '93. .Some observations on Polyclonia frondo.sa. .1. H. V. circ, vol. 12, 1893, no. l(p(i, p. KIO. Brandt, J. F. '38. Ansfiirliche Beschreibnng der von C. II. Martens aid' .seiner Weltum.segelung lieoljarhteten Scliiruniuallen. Mem. Acixl. imp. sei. St. Petersbourg, sci. math, pliys. et nat., (0) vol. 4 (pt. 2, sci. nat., vol. 2), I.S38, pp. 394-399. Brooks, W. K. '86. The life history of Hydroniedusae. a di.scnssion of the origin ot medu.s.ae and the signilicance of metagenesi.s, Mem. Boston soc. nat. hist., vol. 3, no. 12, 188(i ; also Mem. biol. lab. Johns Hopkins Univ., vol. 1. Claus, C. '77. Studien iiber die Polypen und Quallen der Adria. Denk.sehr. d. matli.-naturw. Classe d. k. Acad. d. Wis.scn- schafteu, Wien, Bd. 38, 1877, '81. Ueber einige bLslang noch unbekannte Larvenstadien von Khizo,stoma. Zool. Anz., 1881, No. 70, p. 79. '83. Uutersuchungen iiber die Organisation nnd Entwicklung der Medu.sen. Prag and Leipzig, 1883, 90 pp., 2(1 pis. '84. Die Ephyren von Cotylorhiza und Rhizostoma. Arb. zool. Inst. Wien. vol. .'>, 1884, p. 109. '90. Ueber die Entwicklung des Scyphostoma von Cotylorhiza, Aurelia, und Chrysaora. 1. Arb. /.ool. Insl., Wien, vol 9, 1890, p. 29. '92. Ueber die Entwickhmg des Scyphostoma von Cotylorhiza, Aurelia nml Chrysam'a, sowic iiber die .systemati.schc Stellung der Scyphomediisen, II. Arb. a. d. zool. In.st. (}. Univ. Wien, vol. 10, 1892, pp. 1-70. 232 ROBERT PAYNE BIGELOW ON du I'lessis, G. '81. Ueiniirques sur les metamoi-phoses de la Cassiopfee bottrbonnieune. Biill. sue. vaudois, Lausanne, ser. 2, vol. 17, 1881, p. 033. Fewkes, J. W. '82. Notes on acalephs from the Tortugas, with description of new genera and .species. Bull. nius. cunip. Zuol., vol. 9, no. 7, 1882. Fischer, P. '88. Note siu- des soyphistomes de meduse acraspede. Bull. soc. zool. de France, vol. 13, 1888, p. 96. Forskai, P. 1775. Descriptione.? animalium .... quae in itinere oriental! observavit. Hauniae, MoUer, 1775, p. 107. 1776. Icones rerum naturalium, quas in itinere orientali depiugi curavit. Hauniae, 1776, pi. 31. Frautzius, A. v. '53. Ueber die Juugen der Cephea (Cotylorhiza.). Zeitsclir. f. wiss. Zool., Bd. 4, 18.53, p. 118. Goette, A. '87. Entwicklungsgeschichte des Aurelia aurita und Cotylorhiza tubercidata. Hamburg and Leipzig, 1887. '91. Claus und die Entwicklung der Scyphomedusen, Leipzig, 1891. '93. Vergleichenden Eutwicklung.sge.schichte von Pelagia noctiluca Per. Zeitschr. f. wiss. Zool. Bd. 55, 1893, pp. 645- 695. [Die Larven von Cotylorhiza tuberculata L., pp. 045-659.] Gray, J. E. '69. Habits of the Medusae. Annals and mag. nat. hist., ser. 4, vol. 4, 1809, p. 295. Guppy, H. B. '82. Habits of Scyphomedusae. Nature, vol. 27, 1882, p. 31. Haacke, W. '85. Pseudorhiza Haeckelii spec, nov., der Endspross des Discomedusenstammes. Biol. Centralb., vol. 4, 1885, p. 291. Haeckel, E. '69. Crambessiden. Zeitschr. f. wi.ss. Zool., vol. 19, 1869, p. 509. '79. Das System der Medusen. Jena, 1879. '81a. Report on the deep sea medusae. Challenger reports, zool., vol. 4, 1881. '81b. Metagenesis and Hypogeuesis von Aiu-elia. Jena, 1881. Hamann, 0. '81. Die Muudarme der Rhizoslomen und ihre Anhangsorgane. Jenaische Zeitschr. f. Naturw., vol. 15, 1881, p. 243. Hertwig, 0. & R. '78. Das Nervensystera und die Snine.sorgane der Medusen. Leipzig, 1878. '79. Die Actiuien. Jena, 1879. Hesse, R. '95. Ueber d;»s Nerveusysteui und die Sinnesorgane von Rhizostoma cuvieri. Zeitschr. f. wiss. Zool., vol. 60, 1895, p. 411. Hyde, Ida H. '94. Entwicklungsgeschichte einiger Scyphomedusen. Zeitschr. f. wiss. Zool,, vol. 58, 1894, p. 531-565. Keller, C. '83. Untersuchungen iiber neue Medusen aus dem Rothen Meere. Zeitschr. f. wiss. Zool., vol. 38, 1883, p. 621. Lacaze-Duthiers, H. de. '93. Scyphistome. Archives de zool. expfer., .ser. 3, vol. 1, 1893, notes et revues, p. xxx. Lamarck, J. B. de "37. Histoire naturelle des animaux sans vertfibres. Ed 3. Paris, 1837, vol. 1, p. 457. Lang, Albert. '92. Ueber die Kno.spung bei Hydra und einigen Hydropolypen. Zeitschr. f. wiss. Zool., vol. .54, pp. 363-385. Lendeufeld, R. v. '82. Ueber eine Uebergangsform zwischen Semostonien uml Hhizostomen (Pseudorhiza). Zool. Anz., Jahrg. 6, 1882, p. 380. CASSIOPEA XAMACITANA. 233 '84. Zur Metamorphose der Rhizostomen. Zool. Auz., Jah'rg. 7, 1884. p. 429. '88. Die austialisclieu rliizo-stomeu Meduseii. Zeitsclir. f. wiss. Zool., vol. 47, I.S88, p. 201. McMurrieh, J. P. '91. The Development of Cyanea arctica. Amer. nat., vol. 25, 1891, p. 287. Metschnikoff, E. '86. Embryologische Studien an Medusen. Wien, 1880. Milne-Edwards, H. '49. Les zoophytes. Cuvier, Regne animal illustre. Vol. Ki, 1840, pi. 61. Reid, J. '48. Observations on the development of the medusae. Annals and mag. nat. hist., ser. 2, vol. 1, 1848, p. 2!>. Sars, M. '41. Ueber die Entwickluiig der Medusa aureta und Cyanea capillata. Areh. f. Naturg., vol. V, 1841, p. 9. Schewiakoff, W. '89. Beitriige zur Kenntnis der Aoalephenauges. Morph. Jahrb., vol. 1.5, 1889, p. 25. Schneider, A. '70. Zur Entwickhingsgeschichte der Aurelia aurita. Arch, f. mik. An.at. vol. fi. 1870, p. 363. Schultze, L. S. '98. Rhizostomen von Ternate. Abli. seuckeub. naturf. Ges., vol. 24, 1898, p. 153. [Oocurreuce of Vasskipea, sp.?] Smith, Frank. '91. The gastrulation of Aurelia davidula Viw & Les. Bull. mas. comp. zool., vol. 22, un. 2, 1891. Tilesius, W. G. v. "29. Zur Naturgeschichte der Medusen. Nova Acta Physico-Medica, N. C, vol. 15. 1829, p. 266. Vanhoffen, E. '88. Untersuchungen iilier semaeostonie und rhizostome Medusen. Leuckart & Chun's Biblioth. Zool,, Ileft 3, 1888. Explanation of Plates. All the figures from 1 to 28, and Figs. 34 and 35, are freehand drawings made from the living animals. Figs. 29 to 33 are from well-preserved specimens mounted in balsam, and were outlined with the camera lucida. The remaining figures, except Fig. 37, are camera-lucida drawings of microtome sections. All the figures are reduced uniformly to slightly less than one half the diameter of the original drawings. LETTERING COMMON TO ALL THE FIGURES. b. — bud. c. — columella. c d. — circum-oral di.sc, or iieristome. OS. — circular sinus. ex. — calyx. d. — digitellura. ect. — ectoderm. 6 1. — endodermal lamella, or cathannnal plate. end. — endoderm. e u. — exmnbrella. g. — stomach. ' g f. — gastric filament. .g p. — ga.stric pouch. h. — hood. i 1. — interrhopalial lobe. i t. — interrhopalial tentacle. 1 g. — labial groove. m. — mouth. mes. — mesogloea, or supjiorting membrane. n f. — nerve fibres. o a. — oral arm. oc. — ocellas. o d. — oral disc. oe. — oesophagus. 284 ROBERT PAYNE TUOELOW OX oo. t. — oi>.sopliaf,'i';il tiil)e, iir canal. s e. — sensory ciiilhiliuiii. OS. — oscnlnni. .sep. — .scptnni. ot. — rliiipalial cnncrclion (ntolitli). s f . — septal fiuini'l. p. — prnlxiscis. s g. — subgenital cavily. ]) )). — pillar of llic jirobiLscLs. s ni. — septal muscle. r ('. — railial canal. s u. — .subunibrella. rli. — rliniialiiun. t. — tentacle. rli. I'. — rliopalial canal. v. — vesicle. ill. t. — rliopalial Iciilacle. za. — brownish green cells, .symbiotic algae. s. -ostein. PLATE 31. Fii;. 1. I'orlioii of Ihc calyx anil stem ol a si'ypliisl.niia ivilli a, liilly ilrvclo|icil Imil (h) attached. ^1, the oiillinc ,.| ih,. same Iiiiil when contracted. l'"ig. 2. Similar to the preceding, except for the formation of a second buil (Ij') which bears the older one (6) upon its ajicx. Fig. •'!. 'rill- form of llie ])laniila-Uke bu I daring the fir.-it tw i days after becoming free. A, B, aud C, are the successive clianges in sliajie olisi-rvcd ill one specimen diiriuT; a few minutes. The arrows show the dii'ection in which it swims. Fiii. 4. Larva of prolialily the third day. A, lateral aspect; B. oral aspect. Fig. 5. A larva of alinui the same age, 48 hours or over. Fig. 6. Another larva of 48 hours or 0VCT-. Fig. 7. Larva of the fourth day. Fig. 8. Free scyphi.stoma of the fifth day, with radimeiits of four tentacles. The arrows show the direction of progres- sion and rotation. F'ig. ft. A scypliistouia of ali ■ut the same age, with the ruilimeiits of eight tentacles. Fig. 111. "im1 aspect of a similar hirva, [icrhaps somewhat younger. Fig. 11. A scyphistoma a little iii ire advanced, probably in the fifth day. Fig. VI. A still more advanced .scyphistoma of the fifth day. The four lentacles Hrst formed are uiiieli longer than the other four. . Fig. 13. .Scyphistoma of the sixth day, attached, and with eight tentacles. Fig. 14. .Scypliistouia. with rudiments of the .second set of eight tentacles. Two tentacles of the first series are bifur- cated. Fig. 15. Scyphistoma with sixteen tentacles fully developed, in the attitude of feeding. Fig. 10. Oral aspect of a similar specimen. FLATE ?,■>. Fig. 17. Scyphistoma sliovving first traces of rhopalial structure. Fig. 18. A small jiortion of the margin more highly magnified. Fig. 10. Scyphistoma at a .slightly older stage. Fig. 21). Small part of the margin of a similar larva. Fig. 21. .\ii early stage in strobilization. Fig. 22. A rliopalial tentacle of the same siiecimen seen from the side. Fig. 2.'J. An older rlii>iialial tentacle. Fig. 24. Sti-oliila in which the rhopalial tentacles h.ave begun to degenerate. CASSIOPEA XAMAOHANA. 235 PLATE 33. Fig. 26. St,ri>l)ila, in which the degeneration of the rlmiialial tentacles i.s nearly completed, and the iiiterrhopalial lentacle.s have begun to degenerate. Fig. 26. A complete strobila. The ba.sal polyp bears a bud which broke off and swam away while the drawing was being made. The e|ihyriUa was detached during the following night. The rliopalia are visible through the umbrella. At y, is a pair of twin rhopalia ; couipare y. Fig. 311. Fig. 27. Tiie basal polyii of the same specimen, a few iKuirs after the separation of the ephyrula. Fig. 28. Optical section of the same. Fig. 29. An ephyrula recently set free. Dral aspect. The gastric filaments are visible tlirougli the moutli. x 31. Fig. 30. A specimen of about the same age, showing variations of the maigin at it, lo, x, y and z. X 31. PLATE 34. Fig. 31. Mcjutli parts of a young metlusa in the Aurosa stage. The gastric filaments may be seen through the central mouth opening. X 33. Fig. 32. Oral disc of an older specimen. The oesophageal tubes appear as light areas, one at the junction of each pair of labial grooves. Fig. 33. One of the oral arms from the same specimen as Fig. 32. Fig. 34. Floor of the stomach and the oral arms of an adult viewed from the aboral side. The roof of one subgenital cavity is Eemoved, and a thread is represented as passing through the external orifice into this cavity, at j. The ultimate branches are represented on only one of the oral arms. Fig. 35. Portion of the aboral surface of an adult. About half natural size. PLATE 35. Fig. 36. Section of a young bud. X Zeiss DD + oc. 2.' Fig. 37. Diagram to show the branching of the septal muscles, sni^, sin,„ sm^ ajid siti^, and the connections of the septal muscles of the bud, S7n\, sm',, and sm'.^. Reconstructed from the series of sections of which Fig. 36 is one. Fig. 38. Section through the distal apex of an older bud, showing the attachment of a septal umscle to the ectodermal epithelium. X Zei.ss II + oe. 2. Fig. 39. Longitudinal section of a planula-like larva. D was the distal, and P the proximal, end of the bud while attached. X Zeiss DD + oc. 2, dt. lOd. Fig. 40. Longitudinal section through the posterior end of a swimming larva, in which changes preparatory to the formation of the mouth are taking place. X B &, L J + Zeiss oc. 2. Fig. 41. Similar section of a .slightly older larva, showing the mouth as a small opening not exceeding in width the thickness of the .section. X B & L J + Zeiss oc. 2, dt. 160. Fig. 42. Adradial .section of a scyphistoma a little older than Fig. 9 (6th day). X Zeiss DD + oc. 2. Fig. 43. Obliquely transverse section of a specimen of the same age, showing the greatest width of one septum. X B & L J + Zeiss oc. 2, dt. 160. Fig. 44. A tangential section of an older larva, showing the connection of a septal muscle with the circum-oral disc. X Zeiss H + 00. 2. PLATE 36. Figs. 46 to 47 are consecutive transverse .sections of one individual. Fig. 45 shows the continuity between the endoderm of adjacent gastric pouches at the base of an intenadial tentacle. Fig. 47 is lower, and here the gelatinous .septum com- pletely separates the two pouches. X Zeiss H -|- oc. 2. ^ Unless otherwise iifited, the microscoite was used with the draw tube ni»t dra\vii out. Lenj^tli of tube oit.) = 137 mm. 236 ROBERT PAYNE BIGELOW ON CASSIOPEA XAMACHANA. Figs. 48 and 49 are from the same series. Fig. 48 is the secoiui section below Fig. 47. It just clears the oesophagus. Fig. 49 is through the upper part of the stem. X Zeiss DD + oc. 2. Fig. 50. Longitudinal section of a scyphistoma with sixteen tentacles, probably a little younger than Fig. 15. x Zeiss. UD + oc. 2, dt. 195. Fig. 61. An obliquely transverse section of a fully developed scyphistoma, showiiif; the relations of the septal muscles to the depressions in the circumoral disc. The mesogloea is shaded. X Zeiss B + oc. 2, dt. ir.o. Fig. 62. Part of an interradial section from a scyphistoma a little older than the last. Owing to a slight obliquity of the section, the full extent of the circular sinus at the base of the tentacle is not shown. It extends to the point marked x. X Zeiss C + oc. 2. PLATE 37. Figs. 63 to 56 illustrate the development of tlie rhopalia. Fig. 53. Median section of the interradial tentacle shown in Fig. 52 ; x. marks a corresponding pouit in the two sections X Zeiss H + oc. 2. Fig. 54. A radial section from the base of a rhopalial tentacle somewhat older than Fig. 23. X Zeiss H + oc. 2. Fig. 55. Radial section of a rhopalium in the stage of Fig. 25. x Zeiss H + oc. 2. Fig. 56. Radial section of a rhopalium in about tlie stage of Fig. 26. X Zeiss H -f oc. 2. Fig. 57. Radial section showing the course of a septal muscle in a strobila, at the stage of Fig. 24.' X Zeiss DD -\- oc. 2. Fig. 58. A similar section from a specimen a little older than Fig. 25 -^ x, point of separation between the two discs. X Zeiss DD + oc. 2. PLATE 38. Fig. 69. Median vertical section of a strobila in the stage of Fig. 26 ; x, boundary between ephyrula and basal polyp. X Zei.S8 B + oc. 2. Fig. 60. Portion of section from tlie same specimen, showing the proboscis of the basal polyp ; .r marks same point as in preceding. X B & L | + Zeiss oc. 2, dt. 160. Fig. 61. Median vertical section of a basal polj-p, .stage of Fig. 27. X Zeiss B + oc. 2. Fig. 62. Part of a section from the same specimen, .showing the proboscis, p, and the vestige of tlie former connection with the ephyrula at x. X B & L | + Zeiss oc. 2, dt. 160. Fig. 63. Median vertical section of an ephyrula tliat has recently become free ; x is opposite the opening that formerly led into the cavity of the basal polyp. Cf. Fig. 29. X Zeiss DD + oc. 2. Fig. 64. Median vertical section from a young medusa intermediate in age between Figs. 31 and 32. The section is nearly interradial in position, x Zeiss AA -|- oc. 2, dt. 160. Figs. 65 and 66. Tangential sectitms of the same specimen, parallel to the last, nearly at right angles to an interradius. Fig. 66 is the one nearer the periphery, x Zeiss AA + oc. 2, dt. 160. Printed, August, 1900. MEMOIRS OF THE BOSTON SOCIETY OF NATURAL HISTORY; VOLUME .3. NUMBER DESCRIPTION OF THE HUMAN SPINES SHOWING NUMjB]lii(:AL VARIATION IN THE WARREN MUSEUM OF THfJ ' HARVARD MEDICAL SCHOOL. By THOMAS 1)VVK4HT, M.i:)., T.L.D., Parknian Professor of Anatomy at Harvard University. BOSTON: PUBLISHED BY THE SOCIETY. Januakv, lyoi. JAN 17 1901 7. Description or the Human Spines Showing Nujiekical Variation in the Warren Museum of the Harvard Medical School. By Thomas Dwight. " Judging whether another proves his position is a widely different thing from proving your own. To establish a general law requires an extensive knowledge of the i^henoniena to be generalized, but to decide whether an alleged general law is established by the evidence assigned merely requires an adequate reasoning faculty. Especially is such a decision easy when the premises A. 045, A-4, 764, 504, A-186, 578, 110. " B. 4U3, Y, 381. " C. 208, 297. NUMERICAL VARIATION IN THE HUMAN SPINE. 245 Class IV. Group A. 2(i4. Z. " B. 24. " C. H-3. '- D. 349. 4!t2. 2.57. A-219, A-7. 141. Class V. Gnuup A. i)-7, iSO. o77. " B. 350, 478. "• C. 267, 202. As the above classification necessarily scatters peculiarities (cei'vical ribs for instance) wliich are generally kept together, the folloAving table of the spines and incomplete speci- mens presenting certain peculiarities has been prepared. In some cases of doubtful inter- pretation the same specimen figures in more than one category. This also occurs when one specimen presents more than one of the'se peculiarities. Cervical Ribs: 1. A-30. 649, 729, 306. H-3 (?), 349, 492. 267, 202. Incomplete specimens : 725-2, 9379-37. Rudimentary First Thorack Rib : (4-22, (not rudimentary but small) A-4, H-3 (?). Incomplete specimens : 140,572. Bicipital and Tricipital Ribs : 649, 208. Incomplete specimen : C 1. Fusion of Atlas and Occiput: 561. 24. l)-7 (probal)ly pathological). Incomplete specimens: 7737-3, 9638,9639. 8590, 132 (probably pathological). Fusion of Atlas and Axis : H-3. Fusion of Axis axd Tiiikd Vertebra : 297 (?). 264. Inccmiplete specimens: 4767, 1392. Suppression of a Cervical \'ertebra; H-3. 202 (?). Extra Half Vertebra : 9395-3. The following are among the most remarkable spines: 208, 297, two additional prae- sacrals with the last one sacralized on one side ; 264, fusion of axis and 3d ; Z, fusion of and arrested development of several lumbar vertebrae : H-3. fusion of atlas and axis, sup- pression of a cervical vertebra, an additional lumbar, sacralized on one side; 267, unique anomaly of atlas, cervical rib on one side reaching sternuni, suppression of a thoracic vertebra ; 202. cervical rib to uiainibrium on one side, with the next lib ending in place 246 THOMAS DVVIGHT OX of normal 2d, witli no contact between the cartilages, snppression of a thoracic (or cervi- cal) vertebi'a. Class I. Tiiis class comprises the spines in which there is the normal number of praesacral vertebrae, but in which there is some irregularity of the costal element at the junction of the thoracic region with the loins or with the neck. The former cases are in Group A. the latter in B. The following spines are in Class I. Group A: 615. G-19, 636, 567; Group B : ]. A-30, 649, 729, 306. Groiqj A. The peculiarities of this group are so common that it might have been enlarged in- definitely. Either the costal element of the last thoracic vertebra (19th) is too small, or that of the ne.xt below it is too large. 615. Cat. 9379-4.' Female, white, aet. 63. Vertebral formula : C. 7, T. 12, L. 5, S. 5, (C. 4?). This is the slightest possible deviation from the norm. The only peculiarity is that the last ribs are \ery small, and, though doubtless oi-iginally distinct, are now fused wdth the 19th vertebra. The length of the right one is 3.5 em., and of the left 2.6 cm. The spread of the lumbar transverse processes is normal, increasing to the 3d. The 4th sacral IS a penultinuite. The change of the articulai- processes between back and loins occurs normally. Tliei-e is nothing irregular or transition;d in the sacrum except that only two vertebi-ae articulate with the ilium. Tlie conjagata vera is at the 3d sacral, near the top, The pieces of the coccy.x are fused, and their numljer is uncertain. 1 The fii-st immbev is that u.sed in the dissectiiig-roum, the hitter the one put on when the specimen is entered in the cata- logue of the Museum. I always refer to a specimen under the former number, as it is tiie t.ue under which I have studied it. .Vs both numbers are kept im the s]ieeimen card there is no difficulty in using either. NUMERICAL VARIATION IN THE HU.-MAN SPINE. 'l\t G-19. Cat. 9379-5. Female, white. C. 7, T. 12, L. 5, (S. 5, C. 5 ?) . The 12th pair of ribs are very small. The left one has a minute, but distinct head in a socket, while the right one is even more rudimentary, being incorporated with other parts so as to suggest a transverse process. The left one measures 2 cm. ; the right one is 3 mm. shorter. Seen from the front, the right one continues the line of the heads of the ribs; seen from behind, it is distinctly a transverse process. The 19th vertebra as a whole is thoracic rather than lumbar, the spinous process being thoracic and the change of the arti- cular processes occurring below it. The spread of the lumbar transverse processes is not characteristic, as it is about equal in the lower four, but those of the 4th lumbar have the penultimate outline. There seem to be 9 or 10 sacral and coccygeal vertebrae. The 5th sacral looks very much like a coccygeal fused with the sacrum. Little if any of the 3d sacral touches the ilia, but it has the conjugata vera. Below what I have called the sacrum there are 4 or 5 coccygeals fused together. The 11th pair of ribs measures, on each side, 15 cm. along the concavity. This increase of length is common when the last pair is rudimentary or with lumbar characteristics. Although the spine was not measured fresh, it is evident to the eye that proportion requires that the 19th vertebra be considered thoracic. In this spine the tendency in the 19th to assmne a lumbar character has gone further than in the preceding, one sign of which is the chsturbance of the customary rule of de- velopment of the lumbar transverse processes. (In the two preceding cases there is a tendency for the 19th vertebra to assume lumbar characteristics ; in the two following it is for the 20th to assume thoracic ones.) 636. Cat. 9379-36. Male, white, aet. 28. C. 7, T. 12 or 13, L. 5 or 4, S.and C. 10. The costal elements of the 1st lumbar are separate. The left one seems like a trans- verse process that has not fused with the body, but the right one has both the shape and size of a rib. There is a distinct head in a socket. The length of the right one is 4.3 cm., aijd of the left 2.5 cm. The lumbar transverse processes are very pecuhar, those of the 21st and 22d being uncommonly strong, and those of the last two unconunonly small. The last is very ill developed, suggesting that of a penultimate. On the right they in- crease in length to that of the 23d, on the left to that of the 22d. That is to say, if we consider the 20tb a hunbar vertebra on the left and a thoracic on the right, the 3d lumbar on each side has the greatest spread. The change of the articular processes is normal, 248 THOMAS DWIGHT OK i. e., below the 19th. Tlie sacrum is remarkable in two ways: the lateral masses of the 1st piece rise very high, as though trying to join the last lumbar, and, while a small part of the 3d articulates with the ilium on the right, none of it does on the left. This accords with the downward movement of the thorax and loins on the right. On the other hand the sacrum is normal in having a very strong promontory and the conjngata vera on the 3d. All the .sacral and coccygeal vertebrae are fused. There are probably five of the latter. The measurements and proportions from the fresh spine are as follows. Length of 636. Average length, male. Proportions of 636. .\verage proportions. Neck 12.7 cm. 13.3cni. 20. 5^/^ 21.5 f/^ Back 29.3 28.7 47.3 46.3 Loins 20.0 19.9 32.2 32.2 Total 62.0 61.9 lOOO lOO.O It is clear that the 20th vertebra, as far as proportions go, must be called lumbar in spite of its aping the thoracic region on the right. Very interesting are the concomitant changes in the spread of the lumbar transverse processes; but what is peculiar and not so easy to account for is the apparent effort of the sacrum to encroach on the loins, and the fact that the 24th is somewhat of a penultimate. 567. Cat. 9379-6. Male, white, aet. 59. C. 7, T. 13, L. 4, S. 6, C. 4. In this case the process has gone further and there are 13 pairs of ribs. The 13th ribs have heads, that of the left one being ill marked. The right rib is 4.7 cm. long, the left 4.3 cm. Both are e^ddently more in series with the ribs above them than with the trans- verse processes. The change of the articular processes occurs below the 20th vertebra. Its spinous process, though intermediate, is lumbar rather than thoracic. The external tubercle, especially on the right, is uncommonly developed in this vertebra. The spread of the lumbar transverse processes increases to the 23d. The lateral masses of the sacrum show a tendency (that did not appear in the preceding spine) to mark oft' transverse processes. The 6th piece of the sacrum strongly suggests a fused coccyx. The 3d sacral has a considerable surface articulating with the ilium. The conjugata vera is probably at the 4th sacral. It seems as though the thorax were encroaching on the loins; never- theless the proportions clearly require the 20th vertebra to be con.sidered thoracic in spite of its lumbar peculiarities. These four cases illustrate what may be called the instability of the region at the junction of the back and the loins. It is curious to see how similar the conditions of the NUMERICAL VARIATION IN THE Hr:MAN SPINE. 249 last costal elements are in G 19 and 636, though occurring in the former at the 19th, and in the latter at the 20th vertebra. Group B. This group, like the preceding, has the normal number of praesacral vertebrae, but there is some irregularity in the costal element at the jiuiction of the neck and back. This might consist either in cervical ribs or in a want of development of the 1st thoracic rib. In point of fact the only complete spine with the latter anomaly has to be put in another group. The same is true of several cases of cervical ribs. 1. Cat. 9379-44. • Adult. C. 7, T. 12, L. 5, S. 5, C. imperfect. A pail- of small cervical ril)s, the right one fused, the left free. Length of right rib along anterior cur\e 2.7 cm. It ends free in a sharp point al)Out 1 cm. beyond the trans- verse process. The left one is longer (4. cm.) and much more evidently a rili. with head, neck, and tubercle. All these parts are minute. It also ends free in a sharp pdint directed forward. On the left the so-called costal element of tlie 7th vertebra is present behind the rib, with the usual transverse foramen.' The 1st thoracic ribs are not quite typical, the left one, especially, being uncommonly long and narrow. Though inserted as a 1st rib, it resembles a 2d. The lltli ribs measure 17.2 cm. on the right, and 16.7 cm. on tlic left. The 12th pair is rather small: 7.8 cm. on the right, and 7. cm. on the left. Tile change in the articular process occurs normally. The transver.se process of the 4th lumbar is that of a penultimate on the right, but not on the left. This spine is in most respects, and as a whole, very normal. There is, how^ever, a greater peculiarity tlian the presence of cer\'ical ribs. It is the concomitant change in the 1st thoracic ribs and the lack of development of the 12th pair, hinting at a ten- dency of the thorax to move upward. A-3(). Cat. 9379-31. Black, male, aet. 22. C. 7. T. 12, L. 5, S. 5, (C. 4 ?) . There is a small cervical ril) (jn the left, con.sisting of a minute head, tubercle, neck and shaft, ending free in a point. The length, following the curve, is 2.6 cm. The right costal element of the same vertebra is wanting, probably lost, ftjr there is tlie faintest ' For the explanation of this condition vide Leboucq ('96 -'98). 250 THOMAS 1)WI(4HT ON possible suggestion of a facet on the hody of thr v.-rtehra. and a somewhat oleaver one for the tubercle. The length of the last ribs, following the curve, is 8 cm. for the right one and 5.4 cm. for the left. The spread of the lumliar transverse processes is not typical, and the lateral masses of the sacrum rise considerably. The proportions, measured on the fresh spine, are very correct. There is little to note in addition to the above. It is probable that the lost right cervical rib was the smaller. If that be so, it is interesting to note tliat the smaller last ribs are on the same side as the larger cervical one, indicating a tendency of the left side of the thorax to rise. This would not l)e mentioned, were it not in accord with several other undoubted cases of the same phenom- enon. 649. Cat. 9379-29. Female, white. C. 7, T. 12, L. 5. S. 5, (C. ?) . This is a case of a hU-'ipltaJ rib on tlie right, foi-med by a cervical rib fusing with the 1st thoracic beyond the tubercle. The head, neck and tubercle of the cervical rib are nearly as large as those of the 1st thoracic. The right transverse process of the 7th cervical vertebra is much larger than the left one. The transverse process of the 1st thoracic runs sharply upward "Ik T/dk.^ to meet it, lea^dng a large gap on the right at the back, between the 1st and 2d thoracic ribs. The spinous process is peculiar, being compressed laterally so that the end is long vertically, and suggests two tips one above the other. The lower part of the spine, without showing any great irregularity, is not typical. The last ribs are small, the right one measuring in a straight line 4.4 cm., and the left one 4. cm. It is worth noting that the one on the same side as the cervical rib is the longer ; which is an exception to the concomitant changes so often observed. The change of tlie articular processes is at the iKn-mal place, but rather transi- tional on the right. The spread of the lumbar transverse processes is not cjuite character- istic. The 5th sacral is imperfect on the right side, there being only three sacral foramina. The coccyx seems short, but the number of pieces is uncertain. The cervical region is relatively short,' although tlie 7th vertebra is retained in it. Tlie follcwing measurements are from the fresh spine. 649 Neck Back Loins Total Length of (i49. 11.8 26.9 19.3 58.0 cm. Average length, female. Proportions of 649. Average proportions. 12.1 -20.3% 21.2'-/ 26.5 46.4 46.1 18.7 33.2 32.7 57.3 cm 99.9 100.0 NUMERICAL VARIATION IN THE HUMAN SPINE. 251 (Tlic two following cases of cer\acal ribs are much alike. The last ribs, on the 19th vertebra, though separate, much resemble transverse pro- cesses. The thorax seems, therefore, to have moved upwards.) 729. Cat. 9379-32. Female, wliite, aet. 26. Vertebral formula normal. (The sacrum has 5, and the coccyx 4.) The right cervical rib is small, consisting of a head, neck, tubercle and a minute .shaft ending free in a point. The length, following the ciuve. is 3.2 cm. The left cervical rib is ().2 cm. lonu' and altogether It ends free in a knob to -&-"^-- larger, which shreds of muscle were attached. Just be- hind this is a smooth groove, no doubt for the subclavian artery. It was connected to the first thoracic rib by muscular fibres, having the direc- tion of the external intercostal. There was no internal layer. The pleural cavity extended up to the cervical rib. The 1st thoracic ribs, espe- cially the left, encroach somewhat on the body of the 7th vertebra. The right one is tolerably nor- uud. with two ill-marked grooves. The left one is longer, narrower, and a good deal like a 2d rib. It has a groove, presumably for the vein, just in front of the end of the cer\dcal rib. Seen from behind, the transverse processes of the 7th cervi- cal are abnormally expanded. The proportions of the body of this vertebra resemble those of a 1st thoracic, antl the latter does not have the usual .slight elevation of its superior lateral borders. The costal elements of the 19th vertebi'a resemble closely lumbar transverse processes which have been cut through some 5 mm. from the base, so that the greater part is movable. 729 252 THOMAS DWIGIIT OX The free portion is 2.3 cm. long on the right, and, 2.2 cm. on tlie left. Their spread is greater than that of the tran.sverse processes of the Ist Inmljar. The pleura lined the right one, but on the left this could not be determined. The change in the articular processes is one place too high : between the 18th and 19th vertebrae. The greatest spread in the lumbar region is at the .3d, Init the 2d almost equals it. The li(ja- menta arcuata externa ended at the tijis of tlif 1 1th libs. Some few facts concerning the nerves could be gained. Apparently the formation of the l)rachial plexus (as far as the entering nerves were concerned) was normal. The only nerves in the lumbar plexus that could be identified with absolute certainty on both sides were the anterior crural and the obturator, which were formed by the 2d and 3d lumbar nerves. The right lumbo- sacral cord seemed to come from the 4th nerve rathci' than from the 5th, w^hich latter joined the 1st sacral. On the left nothing satisfactory could be made out. From all this it seems that there was a tendency for the thorax to ascend, and for the lumbar and sacral plexuses to ascend with it. The position of the external arcuate liga- ment implies a similar tendency. In .spite of its lumbar peculiarities the lOtli vertebra has to l)e reckoned as thoracic to maintain tlie proportions as much as may be. Length of 729. Ave: rage length. female. 1' 'roportious. A^ erage proportions Neck 12.:-) ^ 12.1 21.4% 21.2% Back •2B.1 26.0 45.5 46.1 Loins 18.0 18.7 33.1 32.7 Total 56.4 57.3 100.0 100.0 306. Cat. 9379 — 29.' Black, male. This spine is very like the last one. There is the usual number of vertebrae, the sacrum consistmg of five, and tiie coccyx of four. Both these regions are unusually small. The cervical ribs are nmch smaller than those of the last case. The right one, measured along the concavity, is 3.6 cm. The left is rather .shorter, but an injury prevents accurate measurement. Each ends free; muscular fibres, having the direction of the external intercostal, running from them to the first ribs. The subclavian artery crossed just beyond the cervical rib, resting on tlie front border of the muscle. Pretty nearly the same thing may be said of the botUes of the 7th cervical and of the 1st thoracic vertebra as in the last case; but the first thoracic ribs do not touch the body of the former. The 12th ' Dwiulii ("87, p. •')4S. wliei'f it is marki-il ■• easL- :! " iiisleail of ■■ case 2''). NUMERICAL VAIUATIOX I\ TIIK HUJIAX SI'INE. 253 tlioracic ril)s also resemble transverse processes in nuuli the same way. They aj^parently once had heads, but anchylosis made such progress that they look like transverse proc- esses. The transverse processes of the 17th vertebra (lOtli tlioracic) have no articular surfaces, and those of the 18th are broken up like those of the ordinary 19th. The costal element of the 19th does not extend so far outwards as the transverse process of the 1st lumbar. The change in the articular processes is between the 18tb and the 19th, one place higher than usual. The greatest spread in the loins is at the 3d. The measurements on the fresh spine were as follows, whence it appears that the loins are exceptionally long even if (as is clearly right) the 19th vertebra be reckoned as thoracic. Leiigt.li of 30G. Average leiigtli, iii:iK'. Pi-opurtioris. Average proi)ortii)iis. Neck l-i.'i cm. 13.8 -M.X % 'it. 5 9^, Back 25.3 28.7 43.2 40.3 Loins 21.1 19.9 36.0 32.2 Total 58.6 61.9 lOO.cT 100.0 This is a clear case of over-development of the costal elements of the Ttli vertebi'a. and concomitant uiider-development of those of the I'.bh, the thoi'ax apparentlv moving up. The spines of Group B, excepting the one with the bicipital rib, show more or less clearly what with others I am inclined to call a forward or upward moving of the thorax, shown by the over-development of the costal element of the last cei"\ical verteljra, often by mori' or less modification of the 1st thoracic rib, and by tiie under-developnient of the last pair. These concomitant changes may occur on both sides or on one. This moving of the thorax forward oi' backward, either as a whole oi- on one side onh', is a phenomenon that is perfectly well known. How it is to be accounted for on the theorv that such changes are either regressive or progressive is beyond me. Bateson objects, not without reason, to this phraseology ; and instead of speaking of the thorax moving forward (which it does not actually do), he would call it backward hujiioeoslx, jjccause the last elements of the cervical and thoracic regions tend to assume the features of tlie regions behind them. Without disputing the justice of his criticism, I feel that the expression originallv employed of "the thorax moving forward" more readils' supplies a mental image, and saves us from a new word. It is worth noting that in every spine of Class I the proportions have re()uired the 19tb and lidth vertebrae to be reckoned respectively as thoracic and lumbar, whatever mav have been their peculiarities. 254 THOMAS DWIGHT ON Class II. (21, 5G1, 361, X, G-22, A-175, 2.) This class includes spines in which there is an approach, more or less near, to 25 perfect praesacral vertebrae. In the first the 2oth vertebra is almost a sacral one, in the last it is almost a piu'c himbar. They are arranged to mark the steps of this progression as regularly as possible. In every one of this class the 2(jtli is the rertehra fulcralis, i. e., the one ha\dng the largest surface articulating with the ilium. Also in ever}' case there is more or less of a disc lietween the 25th and the 26th. As the degree of sacralization of the 25th has been made the l)asis of arrangement of this class, it has been necessary to disregard the numljer of ribs, and even the synostosis of atlas and occiput. 21. Cat. 9379-7. Female, white, aet. 10. C. 7, T. 13, L. 5, S. 4. (C. 4?). There is some difficulty in decitUng the limits of this sacrum ; but in view of the facts that the 26th is clearly the _/V/cr«/i.s-, and that the 2(lth is a thoracic at least (m one side, I have put the 25tli in the lumbar region though it superficially resembles a sacral vertebra very strongly, and there are only 4 sacrals below it. The coccyx is hard to count, probably containing 4 pieces. There is nothing worthy of note above the 20th vertebra, which has a distinct rib on the riy'ht, 3.7 cm. hmo-, witli a head, and clearly in line with the others. On the left the costal ele- nu'ut has been lost in the preparation. It was almost wholly cartilaginous, from 1 to 2 cm. long. No certain facet for a head can be found. The change in the articular processes is ill marked, apparently occurring, on the right, below the 19th, and on the left, a vertebra lower. The spread of the transverse proc- esses of the loins is aliout the same (excepting the 25th) and is a little greater in the first. The 25th has an ill-marked prom- ontory below it. It forms a part of the convexity of the loins, and there is the slightest suspicion of a promontory alK)ve it. This want of i very definite promontory is characteristic of the NUMERICAL VARIATION IN THE HUMAN SPINE. :bo sacrum of childhood. The lateral masses of the 25th are very sacral in character, touching those of the vertebra below, though of course not fused at tliis early age. They form a portion of the auricular surface, though less than half as much as those of the 26th, which is certainly ihefulcralis. It is probable that the auricular surface extends to the 2d sacral. The disc below the 25th in the dried spine is almost as thick as the one above it. 561. Cat. 9379-15. Male, white, aet. 28. C. 7, T. 13, L. 5, S. 5, C. imperfect. This spine shows a tendency to shorten at the upper end, by the atlas fusing with the occiput, and to lengthen Ijelow, the 25th vertebra not being a true sacral. There is also some confusion at the junction of the back and loins. The fusion of the atlas with the occiput is pretty nearly complete, Ijut the parts of the former are all distinct. On the right the arch tends to lose its incUviduality, while on the left there is a space between it and the skull. The neck and back present nothing peculiar above the 12th riljs, which are very long: 15.3 cm. (m the right. 15. em. on the left, following the conca\aty. The heads are placed higher than normal, encroaching largely on the cartilage above the \-ertebra. The 13th pair of costal elements, though movable, resemble very closely lumbar transverse processes, especially the left one, the right being more slender and rib- like. Each measures 2.5 cm. The change of the articular processes is 1)elow the 2()th vertebra. The first lumbar transver.se proc- esses are .small, after which their spread is about the same. The 5th luml)ar is transitional and unsymmetrical. The body is deeper on the left, and the lateral mass of that side the larger, with a rudiment of a transverse process. It is boimd close to the ilium and probably forms a small part of the johit. On tlie right it does not quite touch the iUum. The 3d piece of the sacrum has no sliare in the auricular sur- s^i. face of the left, and but a very slight one on the right. It is the seat of the ronjvr/afa 256 'I'llo.MAS DWKill'l' OX cera. It is mucli to be regretted that the first ribs liail been cut ii little bevoiul the tu- bercles, and that the spine was not nu'asured when tVesh. It is to be noted that on the left (the side in which tjjc atlas is most free) the l^'ith vertebra is more sacralized, and that on the right (where the arch of the atlas is neai-ly absorbed into the occiput) the l2")th is more nt'arly a noiaiial last lumbar, thus showing an effort to keep the normal niunl)er of praesacral vertebrae on eacii side. Fni'ther on thi' left the costal element of the 20th \ei'tebra is more like a lumbal' traiissfrse pi-ocess, while on the right it is more like a rib, thus showing an effort to kee[) the normal nuinijer of five lumbar vertebrae. The great length of the penultimate ribs is characteristic of a sjiiuc with aborted last ones. 361. Cat. 037'l-17. Female, white. C. 7, T. 12 (13). L. 6 (5), S. -5 (?), C. imperfect. In some respectts like tlu' last, Init an unsatisfactory specimen. There is nothing noteworthy in the neck or back. What is left of the 12th ribs, which have been cut, is perhaps r;itlier unusually large, and placed a little high on the vertebra. The trans- verse processes of the 2(lth \ertebra ai'e \ery rudimentary and suggest that a small costal element has been lost. The change in the articular processes is below the IDth vertebra, and the spine of the 2()th is exceptionally like a lumbar one. The spread of the lumbar transverse processes is greatest at the 22(1 and 23d. The 25th vertebra is sacralized on both sides, most so on the left, but apparently forms at most but a very little of the auricular surface, and on the right none at all. On both sides the lateral masses join those of the sacrum. On the right the line of junction is very plain ; on the left the fusion is nearly complete. The promontory is \'ei'y well detined below the 25th. From the front the sacrum appears normal, except that the coiijiif/dfa rcra is in the 4th piece; but from behind the 5th piece looks \-ery nuich like a fused 1st coccygeal. There is but one detached coccygeal vertebra, the I'est being lost. This one is nearly as large as it should be, but does not show the characteristic shape of a 1st one. There is a general irregularity in this spine Ijelow the 19th vertelna. The condition might be well exi)lained by Hosenbcrg's theory. X. Cat. 113711-13. Male, white. C. 7, T. 13, L. 5, S. 4, C. 4. The spine is a very long one. It is remarkable for the asymmetry shown in various parts, which almost calls for a different notation for the two sides. The 13th pair of ribs XITMERICAL VARIATIOX IN THE HnVIAN SPINE. is rudimeiitarv. The ri!.>J cm lonu- looks like a very thick transverse i)rocess the front of wliicli rises from the side of the body of the vertebra. Looked at from the front, it seems verv uearlv in liiu' with the ribs; from behind, iu line with the transvt'rsc processes. In fact it represents both. The right one, some 3.8 cm. long, is more clearly a composite, for there is a hint of a head of a rib, and also of a separation between the two ])arts. Though these are absolutely one with the 'ibtli vertebra, there is no donbt that the presence of a IMth ])air of rilis is to be admitted. The change in the articular processes is below this vertebra. Its spine, more- over, is more thoracic than lumbar, in short very like that of a last thoracic. The lumbar region, except for the peculiarity of the last vertebra alivady mentioned, is very normal. The length ol the transveisc processes increases to the 3d, and the 4th ('J4th) is a penultimate. The 1st pair of ribs ]irobably tends to encroach on the last cervical verte- bra; but as they are detached, this is not absolutely beyond question. There is. however, no reason for doubting it. as this condition is shown in other spines of this class. The 6tli and 7th cervical vei'tebrae present certain pecul- iarities. There are outgrowths of boiu' from the front of the botUes of both, bnt especially from the former, sug- gesting a lesion. Another from the root of the spine of the 7th extends upwards to the spine of the lith. The transverse foramina of the (itii are double on both sides: 545. a noie o f th e usual size having a small one l)ehind it. The sacrum is of Hve pieces, but the first coccygeal and a part of the second ai-e fused with it. The rest of the coccyx is wanting. The i"ight auricular surface touches the 3d sacral, bnt the left stops jnst short of it. All in all wi' have a pretty noi'inal spine with an extra thoracic Ncrtelna. It was measured in the fresh contUtion, luit the 2(lth vertebra, on acconnt of the fnsion of the costal elements. 262 THOMAS DWIGIIT OX was at that time tliouulit to ]>v liiinliar. and tlie measurementis wci-c made arcordinLiiN . 'V\iv ivsults roiiiparc as follows with the avcrago of lift_\- male hodies. Lengtli of Length, nnile Pro|iorti(iiis A\ eiage 545. average. of 545. ]ir(i|iortions. Xeck 14.5 ctn. ];!.;5 cm. 22.3% 21.5% Back ■28.3 28.7 43.5 46.3 Loins 22 2 19.9 34.1 32.2 Total 65.0 61.9 99.9 100.0 A 4. By transferrhiii- ■).') cm., for a vert(.'l)ra and disc, fi'om the loins to the hacl\ we get the pi'opoi'tiou of the hack 4S.'.I'/; , and'of the loins 28.8%, which is ahout as much out the otlier way. It is worth noting that the proportion of the neck is nearly normal. A-4. Cat. '.1370-11. Male, white. Evidently from an old person. There are exostoses on the spine and a slight twist. C. 7, T. 13. L. o, 8. o, C. 3 or 4. There are 13 ])airs of rihs. The 1st left rii) is rudimentary. The l-Stli are typical last ribs, which is uncommon. The 1st rih on the right is a tolerably normal one. but the left one is narrow, a little shorter than the other, and connected with its cartilage by ligament. The narrowest place, at the subcla\dan trroove, is S nnn. broad. At the end it is about 1 cm. The spine of the lith cervical vertebra is bilid. which is rare among whites. The last rib of the right side is 8.-1 cm. along tlu' concavity, and that on the left 7.8 cm. The change of the articular |)rocesses from the thoracic to the luml)ar type occurs 1k4ow the I'.lth. The spine oi the l^dth is distinctly luml)ai'. On the other hand the spread of the lumbar transverse pro- cesses is greatest at the od (23d), and the ne.xt is a NUMERICAL VARIATION IN THE HUMAN SPINE. 263 regular peuultimate. The lateral masses of the sacrum extend upwai'd towards the transverse processes of the last lumbar, so that this like the last represents a low degree of the freedom of the 25th vertebra. The sacrum and coccyx are all in one piece. Verv little if any of the od sacral forms a part of the auricular surface. The change oi (Urection of the surface occui-s in the od. Here is an evident addition to the thorax with irregularities at both ends of that region. This can hardly be accounted for simply by the failure of the sacrum to advance. It is important to notice that instead of there beiilg a concomitant enlargement of the left 13th ril) with the undeveloped concUtion of the 1st left one, the former is smaller than its fellow. "^5 704. Cat. l.)37U-8. Male, white, aet. 84. (The identity of this spine is not aljso- lutely certain ; that is to say it may not have l)elouged to a white man of 84, but it is a ligamentous preparation like the rest.) A part of the atlas has been cut away. C. 7, T. 13, L. o, S. 5, (C. o ? ) . The 13th ribs are each about -3 cm. long. The change in the articular processes is below the vertebra bearing tliem (2(lth). which has a spine appi'oachiug the lumbar type. The spread of the lumbar transverse processes increases to the 3(1. Tbe 24th and 20th aie penultimate and ultimate lumljars. The five sacral vei'tebi-ae are very normal, except that tlie 1st has the lateral masses rising higher than usual. The change in the curve seems to occui- in the 3(1 sacral. The auricular surface is on three vertebrae. Tlie 1st piece of the cocc_yx is, perhaps, fused with the sacrum, luit apparently this was a change due to old age. It is not fused with the others, which are united into one bone, probably consisting of four pieces ; but this is not certain. The costal elements of the atlas are small, and on the left imperfect. This spine is interesting as, while ha\-ing essentially the same vertebral formula as the last, it is in many respects a more finished spine. In the last the sacrum tended to invade the loins, and both ends of the thorax were irregular. In this the sacrum, though tenchng to rise on the sides, does so nuuli less, and the two ends *P P^ 'l-'-jiJ- .^. 764, 264 THOMAS DWIGIIT ()\ of the thorax are practically normal, as is also the liiiiiljar region. It seems dithcnlt under the circumstances to account for tlie extra vertelirn otherwise than hy an irregu- larity of segmentation in tlie thoracic legion. 0(14. Cat. !i;]71l-lO. Male, white, aet. OS. C. 7. '['. 1:;, L. O, (S. 0? ), ('. imperfect. In many respects this spine is like the hist. The iLlth rihs. which have not been cut, are very long. The right one is 17.7 cm. folhiwing tlie curve, and the left Ki.o cm. The right loth rib measures o.-3 cm., and the left S.l). The latter is a perfect rib. but tiie right one is narrow and nearly straight. The articular processes change below the I'.lth vertebra. The .spine of the 2()th is lumbar. The spi'cad of the tiansverse processes of the loins increases to the od on the left, though the difference is slight. On the right the 2d is rather more prominent than its neighboi-s. The lateral masses of tlie sacrum rise to near the transverse process of the -"ith lumbal'. The coccy.x is imperfect. The sacrinn on the left is clearl}' of six pieces, there being five foramina. On the right the fifth foramen is imperfect. The 3d sacral shows strikingly the change of direction. The coccj'x is broken ; what there is of it. one or two pieces, is fused with the .sacrum. The spine is by no means so normal in its almormality as the last. There are more transitional peculiari- ties at the junction of all the regions except the cervical. A-fS(l. Cat. '.J::i7'.»-4b. Male. C. 7. T. lo. L. o. S. ■), C. (4 ?) . This is an old, distoi'ted siiiiie, w ith main exostoses on the front, cf)miectiuo- neish- boring vertebrae. In most respects it is like the preceding ones, but a shabby specimen. The penultimate rib is long. The Kith ribs measui'e about li cm. and are certainly ribs. The change in the arti<'ular processes is below the "iOtli vertebra, the spine of which is lumbar. The 1st rifi encroaches on the body of tlie last cervical. The bodies of the 2d and '■)(! thoracics are fused without exostoses, Ijut it is probably patliological. The ;id lumbar has the greatest spread of the transverse processes, but those of the 4th lumbar are not typical. The lateral masses of the 1st sacral rise nearly to tlie transverse pro- cesses. The 3(1 sacral probably forms a minute part of the auricular surface. There is something of a transverse groove across its body. That of the 1st coccygeal is fused with the oth sacral. The other cocc\'i;'eal xcrtebrae are united, but their nuinl)er is uncertain. NUMERICAL VARIATION IX THE HUMAN SPINE. 265 578. Ciit. !i:J71l-;i. jMiile, white, old. C. 7, T. 13, L. ■"), S. o, (J. 4. Like the last this is an old distorted spine with a twist and exostoses. The 1st ribs encroach on the 7th vertebra. The rig'ht loth rib measnres 6.6 cm. and the left 4.2 cm. Both the l-!tli ribs wvv loiiu', but injured at the end. The change in the articular pro- cesses is below the "-'(Itli vertebra, the spinous pi'ocess of which is thoracic rather than lumbal'. The transverse processes of the loins increase to the -id. The body of the Sth lumbar is co-ossilied with the sacrum. This 1 consider a secondary pathological change; otherwise the spine would belong in the second class. On the whole the 5th and 4tli lumbars are (juitc ty[)ical. The lateral masses of the sacrum i-ise consideraljl}'. The auricular surface is on three vertelirae. The front of the sacrum is remarkably flat. There is no change of tUrection at its -id vertebra. The 1st coccygeal is fused with the sacrum. The remaining three are in one piece. ]10._ Cat. !)o7l:l-45. M^le, white, aet. 04. C. 7, T. l:). L. 5. S. 5, C. 4. This spine ma}- be very briefly described as not very different from others. The 12th pair of ribs (penultimate) is very long: measured along the concavity the right is 17. o cm. and the left 17. cm. The costal elements of the 2(ltli vertebra differ on the two sides. The right one is a dinnnutive rib, '>. cm. long. The left, also free, is straight, thicker, and more like a transverse process; it is about e(juaily long. It does not reach to the body of the vertebra. The change in dii'ection of the articular processes occuu's below the 19th vertebra. The spinoiis process of the 20th is a typical lumbal- one. The spread of the lunil)ar transverse processes is irregular, but the 24tli and 2")tb are a pretty typical penul- timate and ultimate. The sacrum and coccyx are normal. This again is a spine with an extra praesacral verte!)ra. with the 2()th even more transitional than usual. Measure- ments were taken while the spine was still comparatively fresh, so that the discs had probably not lost any considerable part of their thickness. In the first column the 20th is counted among the thoracic, and in the second among the lumbar. The neck is some- what too short in either case, as is to be expected with an extra praesacral. If the 20tli be lumbar the pro|iortionate length of that region is normal : but it is perhaps better to divide the error, as is the case if we consider it thoracic. 266 THO.MAS DWKJIIT ON Length of 110. Lcnutli, male average. Fropoi-tions of 110. Average proportions. Neck 12.7 cm. ]-J.7cm. 13.3 cm. li).-J'/o 19.5% 21.5% Back 31.7 28.6 28.7 48.8 44.0 46.3 Loins 20.6 23.7 19.9 31.7 36.5 32.2 65.0 65.0 61.9 lOD.O lOo.O 100.0 There is a general .similarity in (lioup A. The most peculiar specimen is that of a nulimcntary lirst rih. The lM)uii(larics ol iIk' thoracic reji'ion sliow a good ileal of varia- tion, sometimes heing clear cut and al oliicrs transitional. Sometimes the 1st ribs en- croach on the 7th vertehi'a. The hnnhar i-euion may, exceptionally, he practically t3'pical. Group B. The spines in this group liave the ad(htional praesacral vertebra in the lumbar region. 493. Cat. 9379-18. Male, white, aet. 37. C. 7, T. 12, L. 6, S. 5. (C. 4 ? ) . The first ribs are large, as is also the 12th pair, which seems to occur in spines of this group as well as in those of the preceding. The right 12th measures along the cvirve 15. cm., and on the left 13.-3 cm. The 2()th vertebra has pretty nearly normal transverse processes. The change of the articular processes is, perhaps, a little transitional above the 19th, but t\ pical below it. The spinous process of the 2()th vertebra is thoracic rather tlian luml)ar. The spread of the lumbar transverse processes increases to the 4th (23d), but the}' are all abont eciual. Those of the 24th and 2oth ai-c tolerably typical of the last two vertebrae. The sacrum is very normal except that the lateral masses rise, perhaps, a little too much. The auricular surfaces pro])ably touch the 3d piece. There is no confiKjata vera. The coccyx consists probably of foiu- vertebrae, so fused together that the number is uncertain, but it can hardly be smaller. Y. Cat. 9379-19. Identity unknown. Male almost certainly. C. 7, T. 12. L. 6, S. o, (C. 3 at least). A very pretty spine. The 12th ribs are cut. but are probably longer than usual. The 20tli vertebra has on the left a small transverse process, the natui-e of w Inch is un- questionable. On the right a free process of about the same length ( 1.7 cm.) . but broader, arises from a corresponchng place at the junction of the pechcle and the lamina, clearly XUMERICAL VARIATION IN THE HUMAN SPINE. 267 oori-espoiifUug to tlie left one. The 'JOtli, in the directiou of the articular processes aud iu the shape of the spinous process, is a lumbar. The spread of the lumbar transverse processes increases to the 3d, below which it is pretty nearly the same. The 25th vertebra lias the thi<-k transverse processes of a last lumlnir, aiul the 2-l;th the puny ones of a penultimate, tbougli they are not typical. .The sacrum. e.\cei)t tliat tlie lateral masses extend \'ery high, and that the canal is not closed in, is a normal one, with a well-marked promontory. The last lumbar faces more downwai'd than is usnal, but there is no false promontory. The od sacral presents a line across the middle of its aiiterioi- surface, mark- ing a change of direction, aud bears a part of tlu' auricular surface on either side. There are certainly three coccygeals, possibly more. In the matter of proportions, judging from the dried spine in the want of fresh measurements, it is clear that the loins are too long. If the 20th vertebra were reckoned a thoracic, they would probably be too short. There would seem to have been an ciTor in segmentation by which there has been pro- duced one hnnbar verteltra more than usual. Except foi- one costal element being free, the 1st is tolerably normal, and so aiv the 24th and 2"it]i, consideri'd as a last two. With (i vertebrae in the region in place of •">. it is impossible to reproduce the gradations of spread of the normal transverse processes. If this condition be due to the non-advance of the sacrum, how is it that the 24th has the features of a penultimate? That the od sacral vertebra is normal, is also noteworthy. 3S1. Cat. '.lo7'.)-lG. Male, white. (J. 7, T. 12. L. (i, S. 4, (J. -3. In many respects this is like the last, but the sacrum is less regular. The 20th verte- bra is a normal lumbar vertebra in all respects, except that on the right there is a rudi- mentary costal element on the front of the trans\'erse process, which is small and project- ing beyond it. It probably was originally free. It does not reach the bodv of the vertebra. In its present condition, fused with the transverse pnjcess. the two do not equal the normal transverse process im the left. The spread of the lumbar transverse processes increases to the od. The fith is a typical last vertebra, and the otli a t\'pical penidtimate. The latei-al masses of the sacrum rise so as nearly to touch the last hnnbar transverse processes. Probalih only two vertebrae form the auricular surface. The transverse line is in the od. The last coccygeal is fused with the sacrum, but ])robal)lv this is a secondary change. There are only three pairs of sacral foramina. There are prob- ably foui- other coccygeal elements, all fused together and now united with the 1st piece; but this union, like that of the 1st piece to the sacrum, is probaijly recent. 208 THOMAS DWK.in- ox Group C. This group t'ontains two spines witli two ivxtra pniL'sacral xrrtelii'ae. tlic .ITtli lieing the ftilcrdlix and tiie 2(ith being saciali/.cd on one side. The one first described is the onl}' spine in tliis series w bicli is not ol iiiy eollecting. It was placed in tlie Museum by my grandfather. Professor .lohii ( '. Warren, in IS47. It is very pathological. The secoud specimen was met with in the season of 1 S',lll-1 '.)(Ml. It is also pathological, but much less so, and several of the changes, no doubt, occurred late in life ; while in the former they are largely dc\ dopmentai. l^OS (old catalogue number.). Cat. '.CiT'.t-oo. Age unknow n, luit the spiiu' is of a iikih w ho had reached, if not passed, middle life. The sex is determined by the ])clvis. ('. 7. T. l:;. L. (i. (S. -V?, imperfect). Like all the others the specimen is ligamentous. The atlas is wanting, and the lower end of the sacrum is lirt)ken off. The right 12th rib is lost, but the cartilage-covered facet for the head is perfect. The sacralization of the 'Jbth vertebra is on the right The spine presents a marked but not extreme spiral scholiosis. not easy to descrilje. It at first rises l)ackwards and to the left, turning fit the 2d lumbar to the right, and again to the left. The chief concavity is on the right of the lower part of the thoracic and the upper part of the lumbar regions. There is a nnich smaller compensatory curve to the left in the upper part of the back, and to the right in the neck. There are uuuiy com- pression changes of the vci'tebrac throughout the spine. The spine is otherwise a pathological one. showing serious early derangement of the course of development. There is fusion of several vertebrae of the l)ack and neck, and of the first three left thoracic ribs. An important feature is the great irregularity of tlie laminae of most of the cervical and of the upper thoracic vertebrae. The atlas is wanting, but there is nothing aliout the odontoid to suggest that it was peculiar. The laminae of the axis meet in the middle and are fused, as shall be described presently, with those of the following vertebrae, but below those fused with it there is want of \inion between the laminae of the two sides, as far as the upper part of the back. The lid. •")(! and 4th vertebrae arc fused at both tlic boilit'S and the arches. The left laminae arc colli'ctcd into oiu' mass, the lower border of the 4th slanting strongly upwai'd. w bile on the right, though fused, they arc tolei-ably normal. The lower border of the 4th NUMERICAL VARIATIOX IX THE IH'.MAX SPINE. 269 left lamiua joins the upper part of the od right oue. Tlie lower part of the 3d and 4th right ones ends free at the median line. The bodies of the last three cervical and of the 1st thoracic are fused, but with their iudi\ iduality preserved. The left lamina of the 5th is broadened and ends opposite to. but not touclnng, the fused right 5th and 6th laminae. On the right these are fused to the tip of the 7th spinous process. The left laminae of the (1th and Ttii and of tlie 1st thoracic are fused, the last being slightly developed and not reaching the middle line. That of the 'Jd thoracic is very broad on the left and joins the right lamina of the 1st. making a spinous process projecting abo\'e that of the right 2d, which had no lamina meeting it on the k'ft. Jk'low this the arches are normal. The bodies of the 3d and 4th thoracics are so completely fused, with but the slightest hint of a separation, that there can l)e little doubt of the condition having occurred at a very early period. There is. perhaps, some fusion between the bodies of the 4th and 5th and of the 5tli and bth. but in any case this is a pathological occurrence of late date. There are 13 pairs of i-il)s. The first three left ones are fused into a single plate at, and beyond, the tul>ereles, which expands greatly at the distal euil wheie it forks into two. The greatest breadth is 5.2 cm. As the sternum is wantinu'. the termination of the ribs is unknown. The 13tli ril)S are broken some (S cm. from the heads. While their length cannot even be guessed, it may be said that they give the impression that they might have been several centimetres longer. What is certain is that they are not rudimentaiy struc- tures. The change in the articular processes occurs between the thoracic and lumbar regions, i.e.. below the 2(lth vertebra. The spine of the 1st lumbar is rather thoracic. - The transverse processes of several of the lumbar vertebrae are injured so that the relative spread cannot be known. The left ti'aiisverse process of the 5th (25th) is that of a penul- timate. Init the riuht one. though broken, is not. The (ith lumbar is sacralized on the left, touching the ilium. It forms, however, but a small part of the auricular surface. It shows signs of compression, and is not a normal nor a typical last lumbar. The next (27th) however, has the promontory above it and is evidently the 1st sacral <)v fulcralis. The sacrum is Ijrokeu off obliquely through the 5th in such a way that almost all the ven- tral surface of that vertebra is lost. Its dorsal aspect is very like that of a fused 1st coccygeal. It is most prob;d)le from the appearance of the parts that the 4th sacral fora- mina were never completed below. The arch of the 1st sacral vertebra is incomplete on the left, but whether from want of development or from destruction by disease or\'iolence, is hard to determine, though thert' are signs of injury. The auricular surfaces reach to the 3d sacral and perhaps extend slightly onto it. While the spine is certainh' very pathological, it is worth noting that the most serious disturl)ance of de\elopmeut is in the neck and upper part of the thoracic region: so that it is not clear how it should stand in any causal relation to the anomalous seg- mentation of the thorax and loins. 270 THOMAS DWIGHT OX 'I'.r, C'iit. it;;7ii-o2. Male, wliite. net. S"). C. T. \>l L. n. S. 0. C. 3. 297. Tliis spine is ;in iincoiiiiiionly laruo one, and shows signs of extreme old age. The bones are very friable, and in some cases liave nnfortuuatelv suffered (Uu'ing preparation. There is a moderate twist in the liaek, but it perhaps is nothing more than a senile exaggeration of the cui've in the cardiae region. Several of the ribs show united fractures; but it is safe to sav that they did not oeeur in youth, and are too far from the eolunni to be of interest in this eon- neetion. There is, besides the numerical variation, no marked distiu'bance in the ordinary process of de- velo])nu'nt. except that the axis and the -"id vertebra are more or less fused. There is no disc between them; but it is impossible to say whether it may not have disappeared as several others have done ; and the laminae are so intimately fused, especially on the right, as to point to a congenital union. The Ijodies of several others of the cervical vertebrae are ccmnected by bou}' growths, while their arches are (juite distinct. My colleague. Dr. Councilman, Professor of Pathology, agrees with me that the union of the bodies occurred late in life. That of the 2d and 3d. however, I regard as possibly congenital. It is known that these two vei'tebrae have a particular tendency to fuse. There are also several exostoses connecting bodies of verte- brae in the thoracic and lumbar regions. The last lumbar (2()th) is sacralized on the left, and its articu- lar surfaces fused with those below it. On the right the sacrum is fully co-ossified with the ilium. in the neck the lowest four vertebrae are con- nected in fi-ont l)y outgrowths from the bodies, especially developed on the right, which have no mor- NUMERICAL VARIATION IN THE HITMAN SPINE. 271 pliological interest. The transverse and costal elements of the 7th are badly injured ; so that it is not certain whether or not a free costal element existed on the left. Certainh'. however, it was not a rib with even a miunte head in a socket, but at most a continuation of the independence of a separate ossification. The appearance on the whole favors the theory of such a piece havinu' i)een lost i-atlicr than broken off. The spinous process of the 6th vertebra is bifid. The body of the 7th seems larger than usual, but is. perliaps, not out of proportion to the large spine. . The thoracic vertebrae, l>i in number, are well formed in the upper part of the region, except for the senile exostoses which begin to appear at the borders of several of the vertebrae near the middle line. In the lower part these exostoses, though not individually large, are more numerous, causing a marked prominence at the edges of the bodies. There is also a suspicion of absorption of some of the bodies at the lower end. The 1st I'ibs are broken, but the head. neck, and tu!)ei'cles on both sides are larger than usual, as, indeed, is the whole spine. The heads enci'oach on the body of the 7th verte- bra. The last thoracic (!20th) has a well-developed loth pair of ribs. The left rib is about 12 cm. long, following the concavity. The right is longer, although broken at the end. The joint of the left one seems to have lost all motion, luit there is no doubt that it once existed. That on the right retains its freedom. The head of the lOtli rib rests against two vertebrae on each side. The same is true of the 11th on the left, but on the right the socket does not encroach on the lOtli thoracic vei'tebra. The 12th rib is wliollv on the same vertebra on the I'ight. but on the left it certainly is against the disc above and perhaps touches the 11th vertelu'a. The loth rib is certainly wholly on the same vertebra on the right, and probaljly on the left, bat the head on both sides is much higher than is usual for that of the ultimate rib. The change in the articular processes occurs below the I'.lth vertebra on the left. Iiut on tiic right the joint is i-ather transitional. The spinous process of the 20th is distinctly lumbar, but the transverse processes ai'e those of a last thoracic. The lmnl)ar vertebrae are si.v in numbei', the last being sacralized on the left. Ex- ostoses and moderate absorption of the bodies are most marked in the first two. The bodies of the od. 4th. and oth, except for some exostoses at the top of the first, are very normal. The transverse processes are too much injured for accurate description; but it seems certain tliat those of the -id and 4th are the lonjjrest, and that there is not the usual increase to the former and subsequent decrease. On the other hand the oth has the small transverse processes of the penultimate. The 6th liunbar (the 26tli vertebra) is certainly a praesacral. A very curious feature is that on the right the body of the 1st sacral via-te- bra rises neai-ly 1 cm. al)ove the level of the lateral mass. The disc below the 6th lumbar is completeh- changed into bone, and from the size of the cicatrix can never have been uf 272 THOMAS DWKilll' OX more than one third of the usual thickness. There is a douhle promontory above and l)elo\v the 2l)th. The right transverse ])rocess is a t\ pieai one of a hist hunhar. That on the left is very thoroughlv saeralize(|. so that it is impossible to draw a line of separa- tion throimh the lateral mass w ith absolutf certainty. It seems, howexer. hardlv po.ssible hy any foKi' de force to make the "Jllth tin- /W/c/v/Z/.s- ; while the l^Ttii maybe made to include all. excepting perhaps a very small part of the whole of the upper region of the aurienlar snrface, and in any ease would seem to have the greatest share in supporting the ilium. The arch of the ^lith \ertebra is se])arated l)y a wide gap ( 1 . o cm.) from that of the 1st sacral, but in the middle the spinous process is continued down to unite with its tubercle. At the place of the articular processes the laminae are united so thoroughly that there is no sign of the joint. It can hardly Ije doubted that this union was con- genital. As for the sacrum, there is little else to say, except that t\ie eoiij/ujata rcrri crosses the od vertel)ra. and the auricular surfaces end at about that level. The coccyx consists only of tlu'ee pieces which are all fused together and also to the sacrum. The lowest piece is so large as to suggest that it is not the last, but there is no reason to believe that any were lost in preparation, especially as particular care was taken. Here is a case of two extra praesacrals which is absolutely indisputable as far as the right .side is concerned and. I think, beyond reasonable doubt on the left. Unlike the pre- ceding case, there had been no great early disturbance of the course of development. I very deeply regret the uncertainty concerning the left costal element of the 7th vertebra, which is wanting, but wdiich mav have been injured. I nrvself believe it was lost. If it be .so, this tallies with the somewhat higher position of the heads of the ribs on the left side of the vertelu'ae in the lower part of the thorax. There is an undoubted addition to the thorax, for the 1st lumbar is practically nin-mal. Another remarkable fact is that, though the 2Gth is not a typical last lumbar, the 2oth is practically a typical penidtimate. Cases of this kind are excessively I'are. 15y far the best is the one which Zaaijer put at Rosenberg's service. There are 7 cervicals, the last bearing ribs. 14 thoracics, and 5 Inmbars. While it is very much to be regretted that the ])reparati(m is not a ligamentous one, I, for m\ part, am stnjngly disposed to accept it. It is more nearly a normal spine, as regards pathological processes than any of the others. The next is my second case. My first one shows in the neck great disturbance of the early progress of the spine, and two of Varaglia's. in which there are several half vertebrae, a still u'reater. These, with the exception of some siren monsters are. 1 l)elieve, all that have been described. XITMERICAL VAIilATloX IN THE HUMAN SPINE. 278 Class IV. This class is coniposi'd of spines in wliicli tlicrc is a teiidencv to the ihniinution of tlie nnnihcr of pracsacral vt'rtel)rae, wiiich teiKk'ncv. however, is not completely successful. In everv casi' the 1^'ith vcrtehra is the f'ti/cf>i/ix. The spiiu's of tiiis class are divided into four groups. Group A cousi.sts of two spines in which there is more or less fusion of two or more vertebrae, which certainly occurred during- the course of development. Group B consists of one spine in which the atlas is fused witli the occiput. Group (J also comprises but one spine, in which tlu*re is a diminution of the cervical vertebrae to six, which loss is partially compensated for hy an achlitioual lumbar saci-ali/ed on one side. In this latter respect the spine belongs in the next group, but it is |)ut l)y itself on account of its gri'at rai'ity. Group D consists of spines in which tiie last lumbar is more or less sacralized. The spines in Class IV are the following. Group A : 2r)4. Z: Group B: 24; Group C : H-3; Group D: ;J4'.), 492, 257. A-2]!). A-7, 141. Groiqj A. Of the two spines in this class, tiu' first e\ddently has great peculiarities dependent on a very early fusion of the elements of distinct vertebrae. In the second the process seems more distinctly pathological, and belonging to a later period. 264. Cat. ••M7;)-ol. Male, white, aet. 8S. C. 7. T. 12. L. o, S. o. C. 4. This spine, besides some exostoses and fusions, prob- al)ly due to advancing age, has one remarkable mal- formation in the cervical region. There is nothing worth noting below tlie neck, unless it he that the 1st coccygeal is fused with the sacrum and (hstinct from the otiier coccygeals. The fusion, on one .side, of the lateral nuxsses of the sacrum and the 1st coccygeal is complete. There are consideraljle irregularities of the nature of exo.stoses on the front of the bodies of the last two 264. 274 . THOMAS DWKiilT ON cer\acals and of the 1st thoracic, with a iliiiiiiiufioii of tlic discs. (Duriiiu- preparation tlie cervical roii'ion hecame detached from the rest, hut (iwini;- to these irregularities there is no possihle suspicion of any error.) The atlas is normal The axis and the :!d vertehra have the hodie.s fused, that of the axis descentUui;- h'ss deeply than usual. The total lentrth of the axis is ahout o.;] cm. The transverse processes of the 2d and :U\ are. on the riuht. nearer tog-ether than usual, hut with sufficient room hetween them for the |)assaii-e of a ijood-sized nerve. On the left thev are smaller and almost touching. Tiie fusion of the laminae is complete: hut while on the right there are evidentl\- parts of two vertehrae, on the left they seem to he one. till (dose examination shows the duality. Two spinous processes are close together, of which the upper is bifid. In the region of the articular facets the depth of these fused vertebrae is decidedly greater on the right than on the left. The 4th vertehra is nearly normal on the front, but on the back the right lamina is reduced in size to make up for the greater size of the double one above it. The bodies of the oth and (itli vertebrae ai-e thoroughly fused, but their arches are distinct. How much of the fusion is a late pathological manifestation, I cannot say. Something in favor of this view is derived from a downward process, evi- dently of this nature, from the bod}- of the (ith to the 7tli. It is very remarkable that there seems to be a particular tendency to fusion between the 2d and od vertebrae; and that there is a family likeness between the specimens. Z. Cat. 9379-34. Male, white. mi(hlle age. Nothing noteworthy was observed in the body before dis- secticm. C. 7. T. 12, L. .">, S. -5, C. o or 4. There is no reason to believe in any error of seg- mentation: but. probably during end^ryonic development, the last three Innlbar and the 1st sacral vertebra were fused into one mass. There is nothing to describe in the neck nor in the back, till we get to the 1 Ith thoi-acic vertebra, the arch of which is ill formed, the huninae being narrow. Apparently there has l)een an iidlannnatorv process in the joints of the left side, both here and in one or two vertebrae below. The change in (hrection of the articular processes is I'alher transitional, beginning above the 12th. The last ribs are short and narrow, especially the left one. The right is 0.3 cm. long and 1 cm. broad. The left is 4.2 cm. lout;- and 7 nun. NUMERICAL VARIATION IN THE HUMAN SPINE. 275 broiul. The bodie.s of the hrst two huiiljar.s are noruial, excepting that both are large and the 2(1 is particularly elongated. The spread of the transverse processes increases to the >id. The hody. arch, and transverse proces.ses of the od hnnl)ar at first appear perfectlv normid. l)iit the lower part of the vertclira is in front continued down, as a smooth mass of hone, to the sacrum, wliirh it joins. From the back of the lower part of this mass are seen projecting on each side two ruilimeutary transverse processes. There is a roughness on the bone on the left, extending to the front from the (jrigin of these two processes. On the right there is a smaller roughness, ccmtined to the side opposite the 4th transverse process. There is but a \aguc hint of any interruption of the bone between the last lumbar and the saci'um. e\ er having existed. Tlie arch and processes of the -id limibar ai-e well developed, but it fuses lielow with the ill-developed parts of the 4th and oth lunibars. The spine of the last is little larger than the tubercle which represents it on ii normal 1st sacral vertebni. Indeed, it is only l)y some care that the arcii of the la.-J.-). Male, white. ('. 7. T. 12, L. -5, S. •"). ('. 4. A i"ernarkal)ly normal spine, the only peculiarity of note Ijeing the tendenc\' to dimi- nution of praesacral vertebrae by the atlas being partially alisorl)ed into the occiput. Tlie bones are fused in front i>retty symmetrically. The laminae forming the arch do not meet in the nuddle. The right one is free, and the left, which is less developed, is fused with the l)order of the foramen magniun. The 1st coccygeal is fuseil witii the sacrum. The other coccygeals, at least three in nuudier. are fused into one piece. Tlicre seems absolutelv notluno- else worth notinu'. 276 THOMAS DWKillT OX (rroup C H-o. Cat. '.l.-i71)-40. Female, prohjililv old. (In.saiie.) ('. (1. T. VI. L. (>, S. G, C. 4. This is a verv rcmarkalile, if not unique, case. Thei'e ai"e only si.K eervical vertebrae, and of these the atlas and a.\is are fused. The fusion is so complete that the only points of separation ari' the intervertebral foramina. The odontoid, the anterior arch of the atlas, and its lateral masses are all indistinguishable. A projection 8 mm. long extends upward, above the rest, presumably from the odontoid. Its front surface is oblique, slant- ing upward and backward, and is smooth, as if luuing rested against some ai'ticulai" facet. The posterior ai'ch of the atlas, however, is well develojjed and shows clearly tlie groove for the vertebral artery behind the articular facet. This facet is very far from normal. It is nearly plane, facing upwards, backwards and inwards. Tlie right one. which is the higher and al.so the longer, is very slightly concave. It is uufortimate that we know nothing of the head. The (itli vertelira would pass as a very fair .specimen of the Tth. It is not possible to speak of the ")th. for the tip of the spinous process is broken. Tlic 7tli vertebra is a 1st thoracic. The 1st pair of ribs, arising from it, is not perfect, but they seem undoubtedly to deserve the designation. The left one, with well-developed head, neck, and tubercle, measures 7 cm. in a straight line fi'om the latter to the end of the shaft, which is rounded and free. By "rounded" is meant, not that it ends in a knob, but that the shaft retains its flatness, the outei- and inner borders rounding off the angles as they turn to meet. Tlie riglit 1st I'ili is cut. so tliat its termination is unknown, but thei'e is no reason to doubt that it was a fairly typical 1st rib. Tlu' last ribs, the \'1\\\ pair, ari' decid- edlv long. consi(k'ring llie small size of this feni:de llioi'ax. The right nu^asures \'l. cm. and the left I i.-i cm. along the cur\'e. There is ;i slight lateral twist in the uppi'r pai't of the thorax, to the right. Se\eral ot tlu' thoracic Ncrtebrae liaxc low bodii's. as if com- pri'sst'd. and most of them are fused Ijy a [)athological process. There are se\eral NUMEI.MCAL \ AKIATIOX IX THE HUMAN SPINE. :77 exostoses iu the places of the intervertebral tUscs. The change of the articular processes occurs hclow the last thoracic (ISth) vertehra. the spiue of which is decidedly lumbar. The 6tli lumljar vcitebra is clearly luml)ai- on the right, and very thoroughly sacralized on the left. There is a promontory l)otli al)()\e and below the body, which is all but com- pletely co-ossitied with the sacrid vertebra below it. The lateral mass on the left shows both a transverse and a costal element. The latter ii[)pears to form so large a jiart of tiie aui-iciilar surface that on tlie left this vertebra (tlie 24th) seems to l)e the fiilcral is. The vertebra above it is on both sides very much like a last lumbar. The spread of the lumbar transverse proc- ess increases to the od, belcjw which it is pretty nearly the same. The left transverse process of the 1st lumbar is smaller than the right. The od sacral vertebra shows tlie transverse depression across the body. It is doiiljttid if the auricular surface of either side touches this vertebra. The coccyx consists of four pieces. The 1st is well foi'ined ; the lower ones are con- fused and distorted to the left. In this spine we see that the thorax has moved upward and that the Gtli vertebra is a typical last cei'vieal. The 1st rib on the left is less like an ordinarv cervical one than a ruLUmentary 1st thoracic. It resembles very closely the specimen of the latter in A-4 and in an imperfect specimen described later (noTD-oS) . It would seem, acccu'dinu- to Kosenberii''s views strictlv interpreted, that while this spine is a pi'iniitive one in the neck, it is one of the future in the loins. He admits very fraid\ly that the two processes working at the two ends of the spine do not by any means always hold the lelation to each other that should be expected. Would it not be more plausible to say that the change at the two ends of the spiue, instead of the discordant action of two tendencies, was the simple action of one, — in other words, that the last cer- vical vertebra beconung a thoracic, the last thoracic one becomes a lumliar, and the size of the thorax is retained ? H-3. Groiqt U. Six cases of pai'tial sacralization of the oth liiml)ar (•J4tli). The' spines differ among themselves in several details, as well as in the degree of sacralization ; but they are ai- rana-ed acconhim' to the latter, which is sliu'lit in the lirst and almo.st complete in the last. 278 THOMAS DWIGHT OX 34!). (Jilt. •.);;7'.i-:)0. White, fciiiak'. iiiiddlc-a-vd. C. 7. T. 12. L. -3, S. -",. (J. 3. There are irre^uularities at tlie juiictimi of the l>ark with the neck and the loins, and of the loiuK with the sacrinn. There is nothing- icuiarkahle in the neck except that thei-e is a verv niinnte cervical rib ou the left. It is so thorouuhh fused with the vertehra, and so small, that it is recog- nized witli difficultv. it ])rojects but sli,i>htl_\- heyond the transverse process. The l!)th vertelii-a has the costal element free on the ri^iit. Imt witliont anv (Hstinct head, and h)okiuu- moi-e like a transvei'se process than a ril». The left one is fused. It is larger than on the liiih I, and nearly like a normal ti'ansverse process. The right one measures 2.2 cm. ; the left about o.2 cm. Botli of them are longer than the transverse processes of the following vertebra. The change in the articular processes takes place below the I'.lth. The heads of both the lOtli and 11th ribs are higher than normal. The lumbar region, excepting the lowest vertebi-a. is very normal. Counting the 20th as the 1st lumbar, the transvers.e processes increase in their sprea 6.0 cm. 1 1.5 2 1.7 3 1.7 4 1.7 5 1.7 () l.H 7 1.8 8 1.8 b.o cm. 1.6 1.7 1.7 1.8 Thoracic 5 1.7 1.9 1.9 1.9 2.0 XUAlEIilCAL VAIMATIOX IN THE HUMAN SPINE. 281 9 1.9 riioracic 10 •2.1 11 2.1 12 ■IM- i±l cm. 1 2.4 ■) 2.5 Luriilmr :5 2.5 2.G- 12.5 cm. 1.9 2.2 2.4 ;i.O cm. 2.7 2.9 3.0 3.2 3.2. Total 4(1, (■) ciii. 15.0 cm. 42.3 cm. A-219. Cat. '.)37'.M7. Male, white. C. 7. T. 12 (11), L. f) (fi). S. and C. 8. The only peculiarity in the neck is the excessive size of the body of the 6th verte- bra, which is compensated by tlie smalhiess of the 7th, and that the spine of the 6th is forked. There are 11 pairs of ribs, the last being about 12 cm. long. The lUtli vertebra is ])eculiar. The articular processes change below it. It has a normal transverse process on the left, but on the right this is more rib-like, being over o cm. long, and showing a tendency to bifurcate at its proximal end. There is no head, and it springs from the pedicle, but the bifui'catiou suggests a representation of a tubercle. The next four verteljrae are clearly lumbar; but the 24th is transitionid, being sacralized on both sides. It, however, is to he counted as lumbar. The spread of the lumbar transverse processes, beginning with the 2()th, is normal, and the 23d is a good penultimate. The sacrali- zation of the 24th is further advanced on the left, Avhere it forms a small part of the auricular surface. On the right it does not touch the ilium. There is a transverse element on each side, more isolated on the left than on the right. The body is completely co-ossified with the 1st sacral. There is a double promontory, of which the lowei- is the real one. The arch is quite distinct in the middle, with a well-developed spine. The 1st sacral (2-Jth) is the /'u/cra/is. There are eight pieces below the 24th vertebra, which seem to consist of 4 sacral and 4 coccygeal. There is a foi-ameu between the sac-rum and coccyx on the right, but on the left it is open. (An injury leaves the latter A-219. 282 THOMAS DWIGHT ()\ statement somewhat (luestiouable. but it i.s made lieeau.se certain appearances of the bone seem to justify it.) In this spine we have, as shown by the 19th, the 24th, and 29th vertebrae, a tendency for the sacrum and loins to move up higher (m the left. A-7. Cat. 9379-21. Male, white, aet. 64. C. 7. T. 11. L. -j. S. -j, (C. imperfect). The cervical and thoracic regions present nothing noteworthy till we come to the lUtli vertebi'a. This has on the right a transverse process of normal shape and origin, but nn- usnally long and broad. The left one is of the usual proportions, but is free. The spinous process is distinctly lumbar. The change in the articidar processes is above this vertebra, though rather transitional on the right. For these reasons 1 have decided to call the ver- tebi'a a lumbar, but with hesitation. The spread of the transverse processes in the loins is irregular ; but owing to the twist of the spine and to sonre injuries of the processes the details cannot be given. The 2.3d is much like a last lumbar and there is no characteristic penul- timate. There is a double promontory, above and below the 24th vertel)ra. It is hard to say which is the greater. The body of the 24th is partially co-ossified witli the one l)elow it, with some slight remnants of a disc persisting. The costal element, strongl}' developed on both sides, especially on the right, fuses with the sacrum. The arch is thoroughly ab- sorbed into the sacrum, and the spinous process is replaced by a tubercle. These facts would induce one to call the vertebra sacral, wex'e it not for its relations to the auricular surface. On the left it has nothing to do with it ; on the right it forms a considerable part. Just how much is hard to determine ; but I believe the 25th to be certainly the fulcralis. Below the 24th are five sacral vertebrae. The conJHr/nfa vera of v. Meyer is in the 3d. The extent of the auricular surfaces downward cannot be ascertained on accotmt of injur}'. There is Init one coccygeal vertebra, the rest liaving been lost. It seems to be partially fused with the sacrum, but this is probably a late-occurring change. 141. Cat. 9379-42. Male, white, aet. 31. C. 7, T. 12, L. 5. S. 5, (C. 3 ?). The neck and back show nothing particular. The change of the articular surfaces is between the 19th and 2()th, except that the left superior joint of the last thoracic (19th) is somewhat transitional. The 20th vertebra is a typical 1st lumbar. The spread of the lumbar transverse processes increases up to the 3d. Those of the 4th are small, as is ct>m- mon in that vertebra. The 24th vertebra is the turning-point of the discussion, and is par- NUMERICAL VARIATION IN THE HUMAN SPINE. 283 141. ticularly interesting ccjn.sidered in connection with that of tlie preceding spine. Tt is very thoroughly sacrulized. The promontory is ahovo it. Below it is a faint secondary promon- tory with a very slight remnant of connective tissue in the middle. The latei'al masses are well developed and nearly symmetrical. It is very hard to decide just how much of the auricular surfaces they form ; but the left half of tliis vertchra forms so large a part of it as to make it very possibly the J)i/cr(i/ls, at least on that side. On the rio'ht it forms a smaller |)ortion of the surface and is not the fnlcrafis. ( )n the back there is a large interval l)etween the arch and that of the next vertebra. Though there nuiy ))e co- ossiHcation at the articidar processes, there seems no doubt that once there were true joints. Another reason for calling this vertebra lumbar is that in that case the coiijugnfa rem passes through the 3d sacral. The C(;ccyx itself is of an uncertain number of elements. The last sacral is I'atlier transitional. It is curious that while with this spine there is more doubt which vertebra is the fn/cral is t\mn liicre was with tlie last, yet the arch of tlie doubtful vertebra in the preceding spine is much moi'e incorporated with the sacrum than in this one. There are several spines in this Class in which one is much tempted to call the 24th vertebra the fukraJis, but I have adhered rigidly to the definition that the fidcrd/in is the one that forms the largest part of the auricidar surface of the sacrum. In some of these this may be true of the 24tii on one side. The greatest objection to the theory of the /'»/- era/is is that (iiowever this matter of the auricular surface may be) the 24th is practically a part of the sacrum, and that if the free portion of the spine is to be considered as an ap- paratus, the 24th must be left out of it, although it be not the fii/cra/is. It is also certain that in several of these spines there is a very transitional arrangement at the junction of the lumbar and sacral regions. The difficulty is a sex'ious one; and should be frankly ad- mitted. I was at one time disposed to reject the fulcraVis on tliis account. The fact that instead of a certain vertebra we sometimes find one or more transitional ones, does not force us to deny the existence of that vertebra in a particular form in the innuense major- ity of cases. It must be admitted tfiat tlie specimens in Grou[) I) of this Class tall}- very well with Rosenberg's view. The fact that tlie 23d so often has the features of a penultimate lum- bar seems to me to sj)eak for this interpretation, for T do not see how the assumption of sacral characters by the 24th, in the absence of a vital principle, can affect the details of the transverse processes of the 23d. More difficult cases to account for in this way are found in the next class. 284 Tiio.MAs jiWK.iri' on- Class V. This class comprises seven spines, in each of which there is a ])raesacral too few, tlio 24th vertebra l)eing the fulcralis. In Group A. of tln-ee spines, a vertebra is wanting in the lumbar x-egion. In B, of two spines, one is wanting in the back. In (Iroup C, con- sisting of two very rare spines, there are 12 pairs of ribs, perfect at least on one side, and only six ribless vertebrae in the neck. The spines are : Group A : D-7, 85, 377 ; Group B : 3.5(1, 478 ; Group C : 267, 202. Group A. D-7. Cat. 0370-20. Male, white, very old. C. 7, T. 12, L. 4, S. and C. 0. The spine is a very large one. The atlas is well shai)cd. luit was evidently co-ossified with the occiput, though only a large fragment remains of bone i>artially filling the sockets and rising above the anterior arch. It is i)robable that this is a pathological change, occurring late in life. The 11th ribs are evidently very long, Init having been cut, the length is unknown. The 12th pair are clearly rilis about 5 cm. long. The change of articular processes, however, occurs above the last thoracic (10th), which has a decidedly lumbar spinous process. The spread of the lumbar transverse processes is about the same after the 1st. The 24th or 1st sacral vertebra is thoroughly, and nearly symmetrically, sacralized. The promontory is above it, but there is a very slight false one below it. The arch is thoroughly incorporated with the ne.xt vertebra. Thoiigli the line of de- markation between this vertebra and the next below it in the auricular surfaces cannot be made out, 1 feel justified in calling this the fii/cra/is. The auricular surface rests on three vertebrae. The conjurjata vera is probably in the 3d, though there is a hint of it in the 4th also. There are six pieces in the sacrum, l)ut the last is probably the 1st coccygeal. Below this there are three pieces of the coccyx, of which the upper is free and the two lower fused. From the lOth, inclusive, downwards the spine is peculiar with a general blurring of characteristics, and an increase of the transitional features. It was too much affected by the changes of age to permit measurements. The theory of an undue advance of the ilium, and consequent (listui'l)ance of the regular progress of development, would in this case offer a ver\' plausible explanation. NUMERICAL VARIATION IN THE HUMAN SPINE. 285 85. Cat. 9379-43. Female, white. C. 7, T. 12, L. 4, S. and C. 10. A delicate spine. Nothing to note in neck nor in back till the 12th thoracic is reached. The 12th left rib, abont 4.5 cm. long, is clearly a ril) with a head and a sub- costal groove. The right one is lost, but there is a facet for the head on the root of the pedicle in a corresponding place to that for the left one. The change of the articular surfaces occurs above this vertebra (19th), but is rather transitional on the right. The spinous process is thoracic rather than lumbar. In the lumbar region the spread of the transverse processes is greatest at the 3d. The 4th has rather the appearance of the penul- timate. The 24th vertebra is the 1st sacral. The promontory is above it, and there is the merest hint of a false one below it. On the right the transverse process is more out- lined than on the left. On the left this vertebra is the fidcralis beyond any possibility of doubt; on the right it is less certain. The arch is fused with the rest of the sacrum. There is a faint line of change of direction across the body of the 3d sacral, at about the level of the lower borders of the auricular surfaces. The sacrum is of sLx pieces, but the last beyond question is the 1st coccygeal. It is thoroughly fused so as to inclose a fifth sacral foramen. There are four coccygeals below this, but the highest of them is too small to pass for a normal 1st one. The following measurements were made on the fresh spine. L engtli of 85. Neck 11.8 cm. Back 25.4 Loins 15.2 Total 52.4 Average length, female. Proportions of 85. Average proportions. 12.1 cm. 26.5 18.7 5L3 22.5 % 48.5 29.0 100.0 21.2 % 46.1 32.7 100.0 Two things are apparent : first that the spine is a short one, second that another ver- tebra in the loins would go far to re-establish the proportions. Hence it is evident that the compensation in this case is slight. 377. Cat. 9379-25. Female, white. C. 7, T. 12, L. 4, S. 5, C. 4. A praesacral vertebra is wanting ; but there is some doubt whether it is lost from the thorax or loins. There are 11 pairs of ribs, and the 19th vertebra has neither ribs nor transverse processes. The bod^ has no certain facet for the head of a rib, but there is the 286 THOMAS DWIGHT ON suggestion of a small one on either side. It is probable that minute costal elements have been lost. The change of the articular processes is above the lOtli, the spinous process of which is transitional. The transverse processes of the 20th vertebra are injured; but it seems that the spread in the lumbar regions is not normal. Those of the 4th lumbar (23d) are much like those of a last one ; but there is no penvdtimate. The 24th is the 1st sacral and the fiilcralls, with a distinct promontor}' above it, but its arch is more like a linnbar one than that of the 1st sacral should be. There is no secondary promontory. The auricular surfaces extend onto the 3d sacral. There is no conjucjata vera. The sac- rum has six vertebrae, but the last is evidently the l.st coccygeal. The 2d coccygeal is attached to the 1st, but the union is, probably, not bony. The 3d and 4th are fused together and separate from those above. In the absence of measurements of the fresh spine the height of the bodies has been taken. It is clear that the proportions are rather more accurate if the 19tli be counted as a thoracic and not as a lumbar. As far as its morphology goes, it could be put in either region. Average height of Height of bodies of bodies of 20 spines. No. 377. 1.3 1.3 1.3 1.3 1.5 8 1.2 4 1.2 Cervical .5 1.2 6 1.1 7 1.3 6.0 1 1.5 2 1.7 8 1.7 4 1.7 Tlioracic h 1.7 6 1.8 7 1.8 8 1.8 9 1.9 10 2.1 11 2.1 12 ■) --J 22.1 1 2.4 2 2.5 I.uiiiliar 3 2.5 4 2.5 5 " fi 12.5 6.7 1.8 1.8 1.8 1.8 1.8 1.9 1.8 2.0 2.0 2.2 2.3 2.6 - ^3.8 2.8 2.9 3.1 3.2 12.0 Total 40.6 cm. 42.5 cm. NUMERICAL VARIATION IN THE HUMAN SPINE. 287 This seems a very good iustiince of the suppression of a praesacral vertebra, the 24th being the fulcralis, though its arch is not typical. (I feel called npon to mention that this spine fell into two pieces, parting below the lUth vertebra, which are now artificially joined. The accident happily did not occur in the original mounting, but subsequently, so tliat it is certain that no vertebra has been lost.) Group B. 350. Cat. 9379-23. Female, white. C. 7, T. 11, L. -3, S. u, C. 5. There is nothing noteworthy in the neck. There are only 11 thoracic vertebrae. The ribs are cut, but the 11th pair is probably larger than the usual 12th one. The 18th is very nearly, if not quite, a typical last thoracic. The head of the rib is in about the normal place for that of the last one, and the head of the rib above it for that of the penul- timate. The change of the articular processes is below the 18th. The spread of the lumbar transverse processes is irregular. The last lumbar (23d) has the appearance of the penultimate. The 1st sacral is in some respects rather transitional. There is a distinct promontory above it, and a slight secondary one below it. The transverse processes are too clearly defined. While I Ijelieve it to be the fulcrafis, I nuist admit that there is a want of abso- lute certainty. The arch is very thoroughly fused with the next vertebi'a on the right ; less so on the left. The spinous process is too long. The articular processes descend onto the 3d sacral. The interpretation of the lower part of the sacrum is rather difficult. There are seven pieces ; but the last two are to be considered as coccygeal. A lower detached portion of the coccyx probably consists of three pieces. The fusion of the first two pieces both with each other and with tlie sacrum, is very thorough. Tliere are five pairs of sacral foramina. Again in the absence of f-esh measurements we have recourse to the height of the vertebral bodies. It will be seen that by transferring the 1st lumbar to the thorax, the proportions will become a little more normal ; but in view of the reasons for considering the 19th a lumbar it does not seem advisable to make the change. 288 THOMAS DWIGIIT ON 'JJJW J) I \ r ./N-> Cervical Thoracic Lumliar Total Average heiglit of Height of bodies of bodi ies of 20 spines. ^ No. 3.50. 3 1.2 1.2 4 1.2 1.1 f) 1.2 1.3 6 1.1 1.2 7 1.3- 6.0 1.5 6.3 1 1.5 1.6 2 1.7 1.8 3 1.7 1.9 4 1.7 1.8 5 1.7 1.8 6 1.8 1.8 7 1.8 1.8 8 1.8 1.9 9 1.9 2.0 10 2.1 2.1 11 2.1 2.3 12 2.3- 22.1 20.8 1 2.4 2.6 2 2.5 2.8 3 2.5 2.9 4 2.5 2.8 5 2.6 - 2 9 12.5 14.0 40.6 cm. 41.1 em. 478. Cat. 9.379-22. ■y))ikV- ft x.i,'; 478. Male, black, aet. 41. Height 154.2 cm. Well shaped. C. 7, T. 11, L. 5, S. andC. 9. Atlas lost, but axis quite uormal. Nothing remarkable in neck, except that the right costal element of the 7th vertebra is imperfect. The ribs being cut, the size of the last is unknown, but they probably were large for last ones. The position of the heads of the 10th and 11th pairs of ribs were those of a normal 11th and 12th. The last two thoracic vertebrae are nearly typical. The change of articular processes below the 18th is rather transitional. Excepting this, the 10th and 11th thoracics are like the normal 11th and 12th. The head of the 9tli ril) is more symmetrically placed between two bodies than that NUMERICAL VARIATION IN THE HUMAN SPINE. 289 of the antepenultimate should be. The spread of the transverse processes of the loins is normal, increasing up to the 3d. The 5th lumbar is much like a last one, but the 4th has not the characteristic transverse processes of a penultimate, though they are more slender than those above or below them. The sacrum consists of six vertebrae, of which the last is to be reckoned the Ist coccygeal. It is thoroughly fused, but does not complete a pair of sacral foramina. The 1st sacral (24th) is a typical fulcralis, with the promontory above it. It is quite sacral behind, and, indeed, would be perfect were it not that the transverse processes are a little too well defined. The auricular surfaces extend at least half way down the 3d sacral. The three lower pieces of the coccyx are fused into one. From measurements made on the fresh spine we can compare both the actual and the relative length of the regions with the average. In so doing we ignore the fact that this spine came from a negro. L ength of 478. Average length, male. Proportions of 478. Average proportions, Neck 12. (J em. 13.3 cm. 22.0 % 21.5 % Back i>5.lj 28.7 44.6 46.3 Loins 19.2 57.4 19.9 61.9 33.4 100.0 32.2 Total 100.0 It is clear that there has been l)ut a slight effort to compensate for the want of a ver- tebra in the back by a greater height of the persisting ones. This specimen is a very important one. Not only is the 24th evidently the Julcralis, but in spite of the absence of one thoracic vertebra, the lower end of the thorax is almost typical and the same may be said of the lumbar region. Should anyone doubt that the 24th may be n fulcralis I should refer him to this specimen with perfect confidence. The spines of Group B of the last class and of Groups A and B of this one are in a tolerably good series to show the progressive sacralization of the 24th. Holl in 1882, although not denying that the 24th might be a. fulcralis, declared that he had never seen it. I was first inclined to put in Cla.ss V two spines that are now in Class IV. At first I thought the 24th the fulcralis, and later decided that it pi'obably was not. In all the cases in this class I believe the 24th is the fulcralis, but I feel that in one or two instances it might be difficult to prove it to any one who refused to accept it. Group C. The next two spines are both very remarkable. On one side each has a perfect rib from the 7th vertebra to the sternmn, and the second specimen has the next rib on that side passing to the junction of the manubrium and body of the sternum. One would be almost 290 THOMAS DWIGHT ON 267. inclined, especially in the latter case, to classify them as wanting a cervical vertebra, but the cervical rib in both cases is imperfect on the other side. It is held therefore that a thoracic vertebra is wantiny. 267. Cat. 9379-30.1 Male, white, aet. 20. Height 170.5 cm. C. 7, T. 11, L. 5, S. 5, C. 4. This spine has an absolutely unique malformation of the atlas that shall be described after the other peculiarities. The 6th cervical vertebra has a long spinous process like that of the normal 7th. The anterior transverse tubercle is large on the left (on which side the cervical rib is less developed), and small on the right. The body of the 7th cervical is deeper verti- cally than that of the average 1st thoracic. It has a facet for the head of each cer^dcal rib near the top of the body, and a slight upward deflection of the lower border above the socket for the head oi the 1st tho- racic rib. The spinous process is a repetition of the preceding. Seen from behind, the transverse proc- esses rise towards their ends like those of a 1st thoracic, which on the whole the vertebra resembles very closely. The 8th vertebra has nearly a whole costal facet above, and a very small part of one below. The upper surface is plane, instead of being concave transversely, as a first thoracic should be. The spinous process also is more compressed towards the end than that of a 1st. The 16th (9tli thoracic) is like a 10th in having no facet on its lower Ijorder. The 17th bears on the right iThis spine was described (I)wiglit, '87) t.ogetlier witli .spine 300. By an uniorLunate mistake, for wliioli I am not responsible, tlie atlas of this spine was marked " case 1," the rest of this .spine "case 2," and the other spine "case .S." NUMERICAL VARIATION IN THE HUMAN SPINE. 291 the whole of the liead of the 10th thoracic rib, but on the left the facet extends onto the disc above. The transverse processes have facets for the costal tubercles and resemble those of the 10th thoracic more than those of an 11th. The 18th (11th thoracic) is almost a typical last one. The change of the articular processes occurs l)el()\v it. The spinous process is rather lumbar, but the facets for the heads of the ribs are a little too high. The lumbar vertebrae are, on the whole, very normal, but the trans- verse processes after the 1st have nearly the .same spread. Those of the 4th lumbar (23d) are not those of a penultimate. The 5th is a good last lumbar. The sacrum, which is cut on the right, is very normal excepting, perliaps, for the too great rise of the transverse elements. The 1st sacral is evidently ihe fukralifi. The promontory is single and charac- teristic. The auricular surfaces just encroach on the od sacral. The change of direction of the surface of the sacrum occurs on this vertel)ra, l)ut there is no distinct conjmjata vera. The coccyx has four pieces and is (|uite normal, the 1st vertebra being typical. Tlie 1st rib on the right, coming from the 7th cervical vertebra, is very like a normal 1st one placed a vertebra too high, except that beyond the tubercle it is rather small. A straight line from the back of the tubercle to the end measures 7.8 cm. The concave edge is 8 cm. long. The breadth a little behind the junction with the cartilage is 17 mm., a little less than usual. The costal cartilage when fresh was 5.5 cm. long. It joined that of the next rib, the two occupying all the lateral border of the manubrium and reaching that of tlie 2(1 thoracic rib. The 1st thoracic rib on the right is a good 2d rib, but uncom- monly broad. The first rib on the left is a cervical rib, with head, neck and tubercle nearly as large as those of its fellow, but with a small shaft which ends in a knob resting on the next rib at about its middle. It measures 6.5 cm. along the concave edge. A groove behind the terminal knob marks in all probability the course of the subcla\aan artery, and a very faint depression near the inner border of the next rib, that of the vein. This latter rib (i. e., that of the 8th vertebra) is very broad, measuring 2.2 cm. at the front, and even more further back where it presents a tuljercle, apparently from a distinct ossific centre, presumably for the rhomboid ligament. The left half of the sternum was lost. The right half shows an upward growth of the manubrium, on the side of which the head of the clavicle rests, above the level of the top of the 1st cartilage. The manubrium and the second piece are firmly grown together, but the others are all distinct. Seven ribs in all reached the sternum, and the next approached it very closely. The lumbar region presents certain curious separate ossifications below the inferior articular processes, which they prolong downward. They are largest below the 2d lumbar, where the right one is 8 mm. long and 7 across. The left one is a little longer and nar- 292 THOMAS DWIGHT ON rower. A smaller one is found on the right below the 3d lumbar, and a still smaller one is found on the same side below the 4th. They suggest epiphyses, but are where there are normally none.^ The peculiarity which makes the atlas unicjue is the total absence of the anterior arch. There are cases in which it is represented by ligament or cartilage ; but here it is simply absent, and the front of the odontoid occupies its place. A strong band, which might be called odonto-atloid ligament, extends from each side of the odontoid outward to each lateral mass of the atlas. The right posterior arch of the atlas is represented by a distinct piece attached at each end by ligament to the rest of the bone. Thus each half of the atlas can move independently of the other. The odontoid projects above the neighboring parts of the atlas and bears a smooth facet on its top, slanting forwards, which rested against a fibrous or fibro-cartilaginous mass separating it from a tubercle on the front of the foramen magnum, a spurious third condyle. The superior articular facets of the atlas were but very slightly concave, and the occipital condyles correspond- ingly flat. It is unfortunate that no measurements of the spine were made while it was fresh, but those made on the dry vertebrae are very interesting as showing how the thorax, in spite of the want of one vertebra, has even more than the usual length by the greater size of the bodies. Height of bodies of No. 267. 1.3 1.3 1.3 1.3 1.6 Average height of bodies of 20 spines. 3 1.2 4 1.2 Cervical 5 1.2 6 1.1 7 1.3 6.0 1 1.5 2 1.7 3 1.7 4 1.7 5 1.7 6 1.8 Thoracic 7 1.8 8 1.8 9 1.9 10 2.1 11 2.1 12 2.3 6.8 1.8 1.9 2.0 2.1 2.2 2.2 2.3 2.2 2.5 2.5 2.5 . 24.2 22.1 1 These ossifications, as well a.s a part of the occiput, are figured iu the .Jounuil of Anatomy and Physiology (Dwight, '87). NUMERICAL VARIATION IN THE HUMAN SPINE. 293 2.7 •2.8 Liimhav 3 2.5 2.6 2.4 1 2.4 •> 2.5 3 2.5 4 2.5 5 2.6 12.5 40.G cm. i.i 13.2 Total 40.G cm. 44.2 cm. While the first pair of ribs is what are usuall}- known as cervical, it might be permis- sible, in \dew of the fact that the subclavian artery on each side passed above them, and in view of the large size of the 7th vertebra and of its transverse process, to say that one cervical, rather than one thoracic vertebra, is wanting. This spine is remarkable as an instance of irregular segmentation, one vertebra being suppressed, while the lumbar, sacral and coccygeal regions are almost typically normal. Rosenberg has apparently overlooked my previous description of this case, for in his paper ('99) he alludes to a similar but less complete case of Gruber's; and does not seem quite convinced that the observation is exact. According to his scheme this case is to be described as one with a primitive condi- tion of the lower part of the neck ; while the lower part of the thorax and all below it have reached almost the maximum of transformation in the direction of the future. It may be questioned whether the almost typical condition of the lower half of the spine (apart from the numerical position of the vertebrae composing it) does not point to a con- dition that has suffered no change. Probably Rosenberg would reply that it is precisely this question of the numeiical position of the vertebrae that is important. To express this differently : let us suppose that the spine had been divided in the middle of the thoracic region and the upper half lost. On examining the lower half all would agree that it is practically a normal spine, because no one woidd know that the last thoracic is the 18th vertebra, and the last lumbar the 23d. It would be taken for granted that they are the 19th and 24th. It does not seem to me plausible that an excessive progress of the ilium should have been accompanied by modifications that reproduce so nearly perfectly the normal conditions. There is an error of the original segmentation. This spine furnishes two independent pieces of evidence in favor of ^dtalism. One is the increase in size of the thoracic vertebrae, by which eleven more than take the place of the normal twelve. The other is the development of the ligaments passing from the sides of the odontoid to the atlas, thus retaining it in position and allowing it some motion. At the same time mention should be made of the modification of the joints between the atlas and the occiput. What made all these concomitant modifications but an influence within the organism regulating the details of growth for the needs of the whole ? 294 THOMAS DWIGHT ON 202. 202. Cat. 9379-53. Female, white, aet. 75. C. 7 (6), T. 11 (12), L. 5, S. 6, C. imperfect. The sternmn and costal cartilages are in place. The interpretation of this spine is not easy, especially as the sides differ. There is some reason to hold that a cervical vertebra is wanting, as the arrangement of the ribs and the costal cartilages shows that the left ril) from the 7th vertebra is a more perfect rib than any ce^■^'ical rib yet described. The sacrnm is less normal than that of the preceding specimen. The bones were extremely friable, which must excuse some inju- ries received in the preparation. There is a moderate sclioliosis in the upjjer part of the back, the convexity being to the right. The left side of the chest is more prominent in front. The manubrium is very asymmetrical. The left half is al:)out normal, except tliat the clavicular notch is more on the top than it should be, and reaches almost to the middle line. On the right the notch is very obliquely placed on the outer border of the bone ; its lower border being more than half an inch below the level of the left one. The inferior border of the manulu'ium is a little lower on the same side. The 6th cervical vertebra, seen from the front, is on the left like a last cervical in the small development of tlie anterior tubercle of the costal element (the anterior transverse tubercle) . The parts were probably in the same condition on the right, but unfortunately are broken. The spinous process rather suggests that of a 7th, but not certainly. The 7th vertebra has on the left a rib NUMERICAL VARIATION IN THE HUMAN SPINE. 295 which is continued by its cartihige to the normal place for the Lst rili, without any communication with the cartilage of the next. The course of the cartilage is pecul- iar inasmuch as it descends much more steeply than usual. The head, neck, and tu- bercle would do perfectly for a 1st rib, but the shaft is narrower, being at the end only 15 mm. It is placed very much on one side, so that the inner border is much more a superior one. The length from the tubercle to the outer l)order of the front end is 6.5 cm. in a straight line. There is a well-marked scalene tubercle with a very deep groove behind it. The groove for the vein is also deeper than usual. The 7th vertebra bears on the right a rudimentary cervical rib. The head, neck and tubercle are only about half as large as those of the left one. The shaft ends free in a sharp point, only 3.2 cm. from the tubex'cle. A curved, pointed pi-ojection, partly cartilage and partly bone, 18 mm. long, arises from the lower bordei- of the right clavicular notch of the sternum and runs upward and outward as if to meet the ril). I am not aware whether there was any con- necting ligament. The riljs of the 8th vertebra are l)oth peculiar. The left one, though ending by its cartilage at the junction of the manubrium and body of the sternum, is in shape Uke a 3d rib. The right one, though having a trace of a scalene tubercle and two faint grooves for the artery and vein, is a 2d rib in length, shape and direction, but rather broad at the end (2 cm.) . It is inserted by its cartilage into the whole side of the manubrium from below the clavicular notch to the lower border. The body of the 8th vertebi-a is flat above like a 2d thoracic. The facet for the rib encroaches decidedly on the 7th vertebra on the right, and probably slightly on the left. The next ribs rest on two bodies, which condition con- tinues to the top of the 18th vertebra. Seven ribs in all join the sternum on the left, and six on the right, besides the rudiment of the anterior end of the cervical one. The pair of ribs arising between the 8th and 9th vertebrae (the place of origin of the normal 2(1 thoracic) end symmetrically at the place of the normal 3d pair. Below tliis the arrange- ment of the cartilages is regular and symmetrical. The left rib on the 18th vertebra is about 15.4 cm. long, following the curve. The right one is broken, but also long. The heads are at the top of the body, encroaching on the disc above it. The 19th vertebra has a small transverse process on the left ; Ijut on the right there is the free head of a minute rib which is broken off about 1 cm. from its origin. It rests on the pedicle rather than on the body. The change of the articular processes occurs on the left below the 18th and on the right below the 19th, which is significant in connection with the concUtion of the first and last ribs. The 19th is the first to have a lumbar spinous process, though it is hardly a tyjjical one. The lumbar transverse processes have the widest spread in the 22d. The 23d has rather small transverse processes and rather resembles a penultimate than a last lumbar. It is hardly possible to doubt that the 24th (the 1st sacral) is the 296 THOMAS DWIGHT ON fulcrahs, but it is so thoroughly sacralized that the line of union of its lateral masses with those of the next below cannot well be made out. The real promontory is above it, but there is a sliglit secondary one below it. The arch is more free than that of a typical 1st sacral should be, and there is something of a spinous process. The conjmjata vera is on the 3d sacral, but is not distinct. The auricular surfaces extend to the lower part of that vertebra. There are six sacral vertebrae, and the sacral canal is closed posteriorly till the last of them. There are five pairs of perfect sacral foraixuna. Tliere seem to be at least three coccygeal vertebrae, but tlie end is broken. The 1st has a very slight development of the lateral parts. It should be mentioned that the articular processes of the 22d, 2.3d and 24th, are more or less co-ossified on the right. The change is pathological. The spine is very remarkable in many ways. In the first place the scholiosis wovdd seem to be the result of the asymmetrical arrangement of the clavicles and ribs at the sternum. The cervical rib of tlie left is the only instance in literature, of a rib from the 7th vertebra going to the sternum without joining the cartilage of the 1st thoracic ril), and of the latter going to the junction of the manubrium and bod}' like a 2d rib. The most highly developed cervical rib, accoi'ding to Gruber, has its cartilage reach the sternum in connection with the one below it. So far as I know, it never before has been seen to go alone. Naturally one is much inclined to call this a 1st thoracic rib a place too high. Were it double, there would be no escape from this classification. The presence on the right of a little projection from the sternum, as if to meet the small cervical rib, would seem to imply that the 1st ril) on this side also was too lugh, but rudi- mentary, as it may be in its normal place. This view is strengthened by tlie resemblance of the 1st thoracic rib on that side to a 2d, and further by the 2d pair of thoracic ribs becoming a 3d pair at the sternal end. The only approach to this case, unless H-3 is to be interpreted in the same way, is Albrecht's ('84), whose paper I have not .seen. Pilling ('94)^ in his notice of it puts the case in Gruber's ('69) fourth class in which the cartilage of the cervical rib joins that of the 1st thoracic. He says that its cartilage ends on a piece of bone which articulates with the sternum by a facet between the clavicular notch and the cartilage of the 1st rib. He does not state where the 1 st thoracic ends." ' Pilling carries on tlie bibliography from the point at which Gruber left it. ^ After this paper had been presented to the Society of Natural History a case was published by Bolk (1900) in which the 7th and 8th vertebrae have re.spectively on both sides practically normal 1st and 2d ribs. The arrangement of the costal cartilages is absolutely that of the first two pairs. " tile transit ". . . . That is the end of tlie uniquene.'^s of my specimen. I entirely agree with Bolk that the spine, which is practically otherwise normal, sliould be said to have six cervical vertebrae. I cannot, however, accept his explanation. He rejects excalation, which he interprets apparently as the disappearance in ontogeny, or perhaps tlie failure to appear, of one particular .segment He dn^ells on tlie complications that must en.sue on NUMERICAL VARIATION IN THE HUMAN SPINE. 297 It is clear, however, that the travelling of the thorax upward has not been symmet- rical ; and that on the right (the side where it is less perfect) there is a small rib on the lUth vertebra, which on the left is lumbar, and that moreover the change of the articular processes occurs a verteljra lower on the right than on the left. This is another instance of the tendency for each side to have twelve ribs somewhere. On the left, where there is a good one in the neck, there is none on the 19th vertebra; on the right where that of the 7th is rudimentary, so as practically not to be a rib at all, there is a small one on the 19th. The arrangement of the lumbar, sacral and thoracic regions in this spine is far less regular than in the preceding. It also, as far as the lower half of the spine is concerned, is far more consistent with Rosenberg's theory. Not so the upper part. This on the left is in some respects suggestive rather of the transformation of the 7th vertebra into a thoracic than of a cervical rib. The arrangement of the cartilages of the 1st and 2d left ribs is unique. On the other hand tlie shape of the rib from the 7tli vertebra is strik- ingly like that of a cer\ica! ril) described by Gruber. INCOMPLETE SPECIMENS. Tlie following specimens are incomplete. All except 7737.-3, 8590, 132, 4767, and 1392 are, I believe, my additions to the Museum. While some of them are of little value, others are rare, and some of them fit in very well to supplement the complete spines. Fusion of the Atlas axd Occiput. Five specimens, of which the last is probably pathological. 7737.3. — An occipital bone and an atlas, evddently congenitally fused. The posterior arch of the atlas is open behind. The left side of this arch is much less developed than the other, and completely fused with the occiput except just behind the lateral mass the loss of a certain segment, .say the (ith, not only in the skeleton, but in the muscular and nervous systems. This is very just; but why assume that a certain individual segment is wanting? Why not assume that between the occiput and the segment whence comes the 1st thoracic vertebra there has from the very beginning been one segment less than usual, and that the cour.se of development has been correspondingly modified ? Bolk's explanation is that the 1st segment, whence comes the atlas, is by no means very stable, and that tlie division between the occiput and the cervical region has in this spine occurred one segment too low. I have practically expressed in tliis paper my belief in the want of stability of the 1st segment ; but what has become of it in ihis case '! We are not told that there are any traces of it in the occiput. Even if it were found more or less incoi'porated with the occiput, it seems to me that it is expecting rather too much of the adaptive powers of nature to have a perfect alla,s, :\.s in this case, come from the segment below the one normally producing it, after the occurrence of an error in development. 298 THOMAS DWIGHT ON where a foramen is found. The front arch is more or less fused with the skull. The lateral masses at the places where the joints should be are completely fused. 9638. — An old Eg3-ptian skull of the 12th dynasty, probably male, four thousand years old, given nie by Dr. John Dane. On the right the posterior arch of the atlas hardly projects from the level of tlie foramen magnum. On the left the arch is free but imperfect, ending posteriorly in a projecting point. 9639. — Base of a .skull, probably male and white, from the dissecting-room a few years ago. It is almost the counterpart of the last, only the greater fusion of the atlas is on the left and the free point on the right. 8590 (Mason Warren Collection). — Probably white and female. Skull, with right half of atlas fused, left half wanting. The right half of the atlas is tolerably well devel- oped. The front part is practically perfect, but ends sharph- near the median hue with a surface that apparently had been covered with fibro-cartilage. The posterior half is less developed, and ends before reaching the median line as a thickening of the border of the foramen magnum without any projecting point. The left half of the atlas evi- dently had been distinct, and was lost. The occipital bone on that side is practically normal with a rather low condyle. 132. — Skull, with atlas fused at the places of the joints. In other parts the atlas is well and symmetrically developed, and quite distinct. There is a hint of an old joint on the left. Probaldy the fusion is a pathological occurrence during life. Fusion of Axis and the Third Vertebra. 4767. — The two vertebrae sawn through near the median line. The place of union of the bodies is very obscure on the front, but clear on section. The axis seems decidedly less long (vertically) than usual. The front \ie\v is nearly symmetrical, except that the transverse processes and the costal elements are nearer together on the left than on the right. The intervertebral foramina, seen from within, are about equal. While the laminae are quite fused, their duplicity is evident ; and there are four tubercles at the end of the double spinous process. The length of the axis from the top of the odontoid is 3.5 cm., the total length of the two vertebrae 5.3 cm. A very curious feature, in view of an observation by Lebouccj, which is considered later, is a linear fissure on the front of the right half of the specimen, which at first sight suggests a repetition of the joint between the atlas and axis. It appears. 4767. NUMERICAL VARIATION IN THE HUMAN SPINE. 299 however, that it is uot between the axis and the fused vertebra, but iu the former, and that, though iu general transverse, it does uot correspond to the line of the joiut. 1392. — The two vertebrae uucut. On the front the place of union of the bodies is marked by what seems to liave once been a disc, now thorovighly co-ossified with the bodies. That of the axis is very notably short, 3.5 cm. The total length is 5. cm. The left costal elements and transverse processes are very much nearer together than on the right, so as to make it highly probable that a nerve in passing out would l)e compressed, although, as in the preceding case, tlie foramina are about equal at the canal. The trans- verse foramen on the riglit is open laterally. Though there is a suggestion of injury, it is probable that the costal ^ element w^as never perfectly developed. The wliole left side of the specimen is smaller than the right. The fusion of the laminae is there more com- plete. The spinous process of the axis is bifid. The right luilf of the spinous process of the 3d vertebra is present, the left one is wanting. Probable Extra Half Sacral Vertebra. 939o-o. — Tlie specimen is the left half of a sacrum and last hmibar, probably from a young person. Tlie Hue of union of the lateral mass of the 1st sacral with that of the '2d, suggests that not impossibly it is a sacralized 24th. The lamina and spinous process of the 1st sacral are widely separated from tliose above, and tliougli in apposition with those of the next below are not fused with them. Lnmediately below the tip of the spine of this 1st sacral is another, smaller tip, coming from the right, which evidently can by no possibility have belonged to a lower vertebra. It is quite distinct from the 1st sacral of the left, but fused with the 2d of tliat side. It can hardly be doubted that there was reduplication of half an arch. Cervical Ribs. 725.2. — Obtained In' uie at Bowdoiu, in 1873. A 7th cervical vertebra with a small rib on the left about 3.8 cm. long, ending in a point. On the right the costal element is wanting. 9379.37. — Male, white. A ligamentous preparation of the last three cervical and the first three thoracic vertebrae, with the proximal portions of the ribs. There is a pair of small cervical ribs, ending free. Measured in a straight line, tlie right one is 3.4 cm. long. The left one is probably about the same, Init the end is broken. The small head of each rib rests on an outgr(jwth from the body some 4 nun. long. The spread of the 1 Tliis term is applied to the piece of bone forming tlie floor of the gutter for the nerve. 300 THOMAS DWIGHT ON transverse processes of the 7th vertebra is distinctly greater than that of the 1st thoracic. The slender neck of the 1st I'ib is uncommonly long ; the transverse diameter of the costo- transverse foramen being about 17 mm. This specimen is a very striking demonstration of Leboucq's view ('96-98) that the cervical costal element is the piece of bone between the two tubercles. In the 7th vertebra the anterior tubercle is rudimentary, so that the costal element is relatively long and nearly transverse. In the 6th and those above it the costal element is short and directed more backwards, being the floor of the groove in which the nerve lies. The gradations are shown remarkably clearl}'. The 6th cervical is also remarkable. The foramen on the right is double. The anterior, which presumably is the costo-ti'ansverse, is not quite round. It measures ti'ansversely a little over 6 mm., and a little less antero-posteriorly. The transverse foramen, almost directly behind it, measures nearly 4 mm. On the left tlie foramen is large, measuring nearly 1 cm. in diameter. There is some indication of a notch at the posterior outer aspect, as if another were partly cut off from it. The foramen on the right of the oth vertebra shows at the back a distinct attempt at a subdivision. Rudimentary First Ribs. 140. Cat. !:)o79.o8. — Male, white, aet. 38. A ligamentous preparation of the last two cervical and the first four thoracic vertebrae, with ribs and manubrium. The first rib on the right is smaller than usual, especially at the part be3'oud the tubercle. It reaches to about 2.5 cm. from the sternum and is then contiuued by cartilage which contains a large distinct calcified piece. The left cor- responding ril) is much smaller. It is strongly curved. The head, neck, and tubercle are not excessively small, though smaller than those parts of the right rib. The distance from the outer edge of the tubercle to the tip in a straight line is -j.(» cm. The Ijreadth near the front is imder 1 cm. It ends free more than 4 cm. from tlie inanulniiun. Whether, as is most probable, it was connected by liga- ment, I am unable to say. The next rib is very like a normal 'id one, excepting in its insertion. The cartilage extends aU along the side of the manubrium, and from the upper part of this cartilage there is a short projection towards the rudimentary rib. The 140. NUMERICAL VARIATION IN THE HUMAN SPINE. 301 stern o-cla\'icular joint is lower and more oblique on the left. The subclavian artery evidently passed over the rudimentary 1st rib. Except that the sides are reversed, this is exceedingly like the state of affairs in spine 202, only there we have a small pair of cervical riljs, and here a small pair of 1st thoracic ribs. 572. — Male, white, aet. 70. The specimen consists of the right half of the sternum, and of the right 1 st rilj, which is small and continued by ligament to a calcification of the cartilasj-e near the manubrium. The distance from the end of the bone to the sternum is about 3 cm. There were six lumbar verteljrae. Fusion of First and Second Thoracic Ribs. C-1. Cat. 9379-49. — Tliis specimen consists of the cervical and upper part of the thoracic regions and of the right half of the upper part of the sternum. The spine was normal. The only peculiarity worth noting is presented by the first two ribs of the right side. The heads of both ribs rest entirely- against the 1st thoracic vertebra, not encroachiirg on the disc either above or below it. The head of the 2d rib is much smaller than normal. There is but a slight interval between the two heads. The tubercle of the 2d rib also is very small and rests on a minute facet at the very upper corner of the end of the corresponding transverse process. At about 4 cm. from their origin the two ribs fuse into a broad plate, on which all marks of separation are gradually lost. A rudi- mentary scalene tubercle on its upper edge separates two slight grooves. The C_i. greatest breadth of the plate, 4.2 cm., is just before it divides into a short upper and a longer lower pi-olongation representing the terminations of the shafts of the ribs. Each is continued by a piece of cartilage to its normal termination. 302 THOMAS DWIGHT ON Of the deductions that may be made from these specimens, some are of merely morphological interest, while others are far-reaching. It is not possible to separate the two groups completely. Terminal Vertebrae and Those at the Ends of the Different Regions of the Spine. — It seems beyond question that certain vertebrae are capable of having the characteristics of those above or below them in numerical order. The last cocc^'geal may be just the same to all appearance, though its number from the atlas may differ by several places. The last sacral and 1st coccygeal are absolutely vmcertain. As the vagaries of the 24th, 25th, 26th, and even the 27th, any one of which may be the fidcralis, are at the basis of the classification adopted in this paper, they need not be discussed here, except in so far as the condition of a given vertebra affects that of others, as foi- instance the effect of a certain vertebra being the fidcralis on the two vertebrae above it and on the sacrum as a whole. It is rather surprising that no effort has ever been made to decide whether sacra could be distinguished one from another according to the particular verte- bra that happens to be the fidcralis. From this series it would seem that there are cer- tain peculiarities which in most cases would enable us at the very least to separate the sacra in which the 24tli is the fidcralis, and those in which it is strongly sacralized, from those in which the 25th or the 26th is the fidcralis. On the other hand slight sacraliza- tion of the 24th and 25th may be very similar. Wliile it is likely that a larger series would show more instances of difficult diasrnosis, I think it would confirm the deductions from the present one, which are as follows : Distinctions between Spines vnth Sacra of Different Nnmerlcal Composition. — I. When the 26th is the fidcralis and the 25tli more or less sacralized, the prom- ontory is perfectly evidently above the former, and there is no secondarj' promontory. The 25th, apart from its sacralization, is a good last lumbar, the disc below it, though much diminished, is always present, and the 24th is always a penultimate. (The spine of a child of ten (spine 21) is the only exception to this rule. The promontory is not over-evident, nor is the possibility of a secondary one to be denied ; but this, it is to be remembered, is a characteristic of the pelvis of early childhood. Spine X is very dif- ferent on the two sides, and I hesitate to affirm that, if looked at from the right side only, there might not be doubt about the position of the promontory.) II. When the 25th is qviite free, the promontory is always unmistakably below it. The 25th and 24th are generally pretty typical ultimates and penultimates. III. When the 24th is sacralized more or less, but is not the fidcralis, tlie position of the promontory is not clear, and sometimes very doubtful, being either above or below the 24th or being double. There is little or no remnant of a disc below the 24th. The NUMERICAL VARIATION IN THE HUMAN SPINE. 303 free portion of the 24tli is generally a part of a good ultimate, and the 23d generally a good penultimate. IV. When the 24:th is the fulcralis, certainly or probably, there is often a secondary promontory below it. The 23d may be a good ultimate or a penultimate, or it may pre- sent features of both. Thus the transverse processes may be thick and broad at the root, like those of a oth lumbar, and toward the tips they may become light by the rising of the lower border, as in the 4th lumbar. The 22d is never a typical penultimate. That of spine 478 is the nearest approach I have seen. Perhaps the 1st coccygeal is more likely to be fused to the sacrum if the 24th be the fulcralis or be much sacralized, but I have great doubts whether its condition is of any value. In brief it appears that the spine adapts itself much more easily to an additional praesacral vertebra than to the loss of one. In the former case, assuming that the addition is in the thorax, the 24th vertebra is or may be a very good penultimate lumbar, while in the opposite case it is not. Rosenberg alludes to a case of Tenchini, as possibly presenting this condition. I have not had access to it. In my series there is no perfect case. Both 478 and 267 approach the conchtion, and present lumbar regions which on the whole are not far from typical, but the more normal condition of spine 7G4, in which the 26th is the fulcralis, is evident. The Variations of the 19th and 20th Vertebrae. — These are familiar to all who have studied this subject, but it may not be amiss to recapitulate some of them briefly. In Class I, Group A, the lUth in G-19 is thoracic, with one costal element free but minute and the other fused like a transverse process; in 636 the 20th, as far as these features are concerned, is much hke it; in 567 the 2()th, though in most resjjects lumbar, bears ribs. In Group B, both in 729 and 306, the change of articular processes is above the 19th ; the former seems to have transverse processes cut through at their bases, and the latter small ribs that have become fused so as closely to resemble transverse processes. In Class II, in wliicli the 2'jth vertebra is more or less sacralized, we find in 561 that the 20th is thoracic with lumbar-like transverse processes; that it is more lumbar in 361; that in X it is more transitional and hard to place, suggesting a diiferent interpretation for the two sides; that in G-22, though rather transitional in some respects, the 13th ribs are typical last ones ; and that in 2, though on the whole lumbar, it has free transverse elements. In Class III, in which there are 25 free praesacrals, the 20th is held to be thoracic in Group A, and lumbar in Group B, but still in the development of the costal ele- ments, the nature of the spinous process, and the place of change of the articular proc- esses, there is absolutely no rule. 304 THOMAS DWIGHT ON In Class IV, Group D, in which the 24th is more or less sacralized, the 19th is on the whole thoracic, but generally with lumbar or transitional features. In Class V, in which the 24th is the fulcralin, we find in Group A that in D-7 the IDth has lumbar features and the change of the articular processes is above it, but that never- theless it is reckoned thoracic. In Group B it is essentially lumbar in both spines. In Group C it is clearly lumbar in 267 and transitional in 202, differing on the two sides. Apparently both these vertebrae are absolutely unstable. It is impossible to decide the number of an isolated one. A 19th may be a typical lumbar, and a 2(lth a typical thoracic. I do not remember to have seen mentioned the fact that when the last ribs are very small or rudimentary, the pair above them is much longer than a penultimate usually is. This is true whether the last pair be on the 19th or the 20th vertebra. Cervical, JRudimentari/ 1st Thoracic, Bicipital and Trlclpltal Rlhs. — The anomalies of the region at the top of the thorax are both more interesting and more difficult than those at the bottom. There we have just seen that one vertebra may perfectly resemble another of a different numerical position ; here it is more doubtful. From the study of these spines and the writings of others, it appears that there is at least one type of a rib which is seen only on the 7th vertebra, and that there is a peculiar form of bicipital rib which is seen only in the thorax. On the other hand, while several instances of defective 1st thoracic rib are very much alike, it is impossible to distinguish them with certainty from cervical ribs. In this series there are ten spines and two incomplete specimens with ribs connected with the 7th cervical vertebra. This includes H-3 in which it is more probable that there is a suppression of a cer\acal vertebra, so that the l.st ribs, one of which is imperfect, should be considered thoracic. There is one case of bicipital rib (649) . There are also the following cases of defective 1st thoracic rib: G-22, not rudimentary but small, A-4, H-3 (if it be not included among cervical ribs), and incomplete specimens 9379-38 and 572. Moreover there are the following cases of fused thoracic ribs : spine 208, tricipital ; and incomplete specimen C-1, bicipital. Among the cer\dcal ribs (putting the doubtful H-3 aside for the present) there are two cases in which their cartilages reach the sternum (267 and 202) . According to Gruber's classification the most perfect form of cervical ribs has the cartilage joining that of the 1st thoracic before reaching the sternum. There is, I believe, no single case on record of a cervical rib having its cartilage end at the place of the normal termination of the first rib, with tlie next rib ending at the junction of the manubrium and body of the sternum, and the cartilages being absolutely separate.' This is what occurs in 202, on one 1 Bolk's case had not appeared. See foot-note on p. 200. NUMERICAL VARIATION IN THE HUMAN SPINE. 305 side. Moreover the rib in this case is peculiar, and remarkable in that it resembles closely one figured by Gruber. It is narrow, twisted beyond the tubercle so as to bring the inner edge up with a prominent scalene tubercle and a deep groove before and behind it. The features of the rib are sharply cut. It may be justly said that one is not justified in de- scribing a type from two specimens ; nevertheless these two specimens are among the best instances of cervical ribs. An unperfect 1st thoracic is very different. It is flat, not twisted, and without either a prominent scalene tubercle or clear grooves. It is of a more negative character. Wliile some moderately developed cervical ribs have something of the twisted appearance of those first mentioned, others ai'e very like the featureless imperfect 1st thoracics. It is absolutely impossible in many cases to distinguish, on an isolated specimen, between a medium-sized cervical rib and a rudimentary thoracic one. The resemblance between the cervical rib in 267 and the thoracic in 9379-38 has been mentioned; the former is rather the more like a normal 1st rib. The rudimentary 1st of A-4 and that from tlie left of the 7th vertebra of H-3, which i.s probably to be similarly interpreted, resemble each other and that of 9379-38 very closely. H-3 is a very interesting and perplexing case. If the ribs of the 7th vertebra are to be considered cervical, we probably have here another instance of a cervical rib of the kind found in 202, though in the absence of the sternum it cannot be certain. I incline, however, to consider them as thoracics placed too high, one of them being rudimentary. Lane (85) reports an interesting case of the converse condition, in which the 8th verte- bra bore on one side a ril) which he considers cervical, that from the 9th being practically a normal 1st thoracic one. Leboucq ('96-98) also reports two cases, considered later in another connection (p. 306) , in which the Stli vertebra bears rudimentary ribs quite like cervical ones. These cases certainly point strongly to the likelihood that vertebrae of different numbers at this end of the thorax also may assume similar features. They show, moreover, how unsatisfactory the terms " cervical " and " thoracic " are in this connection. Bicipital ribs sometimes occur and may be due to the fusion of a cervical rib with a 1st thoracic, or to the fusion of a 1st thoracic with the 2d. An instance of each is pre- sented in 649 and in the incomplete specimen C-1, respectively. In the former the cer- \ical rib soon joins the other, which presents no marked enlargement of its shaft, but the latter specimen shows a great broadening. Indeed it is evident that there are two ribs united even before it branches at the front into a normal 1st and 2d. Several instances of this latter condition have been described, but for the most part without conclusive data as to the number of the ribs. They have, however, a general family likeness and, more- over, one point of resemljlance which perhaps has not been noted. It is the nearness of the two heads to one another. In this specimen they both rest on the 8th vertebra. This last point is very striking in all illustrations (Tui'uer, '83 ; Lane, '84) . While I 306 THOMAS DWIGHT ON believe that these two types are distinct, and represent what is commonly seen at differ- ent levels of the spine, I would not undertake to say that either may not be found some time at the level of the other. In this series there is one case (208) of the fusion of the three upper thoracic ril)s. I shall return to the condition of the spine as a whole in cases of cer\acal and de- fective 1st thoracic ribs. Fusion of Atlas and Occiput. — There is no reason why this occurrence should not have the same weight in the numerical variations of the spine as fusion at other points. There are several specimens in this series which have been sufficiently described. Is this condition a return to the past (if so, to what past ?) , or a step towards the future ? The Fusion of the Axis and 3d Vertebra. — Fusion occurs occasionally as a patho- logical process, usually of advancing years, in any part of the spine. There are also certain places where it exceptionally occurs more or less frequently in the course of development, as between atlas and occiput, last lumbar and 1st sacral, last sacral and 1st coccygeal. There is another place whicli seems one of predilection, namely between the axis and the vertebra below it. Leboucq ('96-'98) has described two cases, both with imperfect ribs on the 8th vertebra, in wliich he thinks there is a partial reduplication of the axis, inasmuch as in certain fissures on the antei'ior surface he sees a repetition of the superior articular siu'faces of the axis placed ventrally to the intervertebral foramina. This is the case only in his first specimen. In the second the fusion is more thorough, and the lines of separation lost. In the latter, moreover, there is an intimate fusion of the arches. I am somewhat inclined to question tlie accuracy of the interpretation because these fissures on the anterior surface, judging from Leboucq's drawing, do not correspond with the direction of the superior ai'ticular surfaces of the atlas. These latter slant from the middle downward and outward, while the fissures are inclined upward and outward. Moreover, in the first of my detached specimens (4767) there is on the right of the anterior surface a horizontal slit below the superior articular process of the atlas that looks at first like a repetition of it, but which, as is shown by the median section, is certainly in the axis and not beneath it. Neither in Leboucq's second case nor in any of my series is there another instance of such an appearance. In this series there are two cases of fusion of these vertebrae without any history of the rest of the column. In the complete spines there are two other cases, one certain and one perhaps somewhat doubtful. The former (204) has the bodies fused and the laminae on one side so intimately mixed as to appear as one. In 297 (20 praesacrals) the bodies are fused but apparently not mixed (if I may use the expression) , but there is a t\ision in the arch that points to a congenital condition. Leboucq tliinks tliere is no dou1)t that NUMERICAL VARIATION IN THE HUMAN SPINE. 307 there is an intercalation of the 3d vertebra, which, at least in one case, he considers a partial reduplication of the atlas. In neither of my cases is there any reason to see more than fusion. Leboucq asks whether we are to consider his finding twice an intercalated vertebra at this place anything more than a simple coincidence. He think.s that the place l^elow the axis is a critical one in the cervical column, and that the 3d vertebra is exposed to more variations than the others. He cites Murie to the effect that the reduction of the cervical vertebrae to six in the manatus arises from an almost complete regression of the 3d. Putting aside the question of intercalation, the idea that this is a critical point receives additional confirmation from the four cases in this series. Irregular Segmentation. — As was remarked earlier, this is much the same as inter- and excalation, but preferable ; inasmuch as the latter terms too often are used to refer to a particular vertebra supposed to be added or suppressed. There are cases in this series both of tlie addition and of the want of a vertebra above the sacrum, in which the regions are well defined and otherwise practically normal. Two striking examples are 764 and 478. The formula of the former is C. 7, T. 13, L. 5, S. 5, C. probably 5 ; that of the latter is C. 7, T. 11, L. 5, S. and C. 9. In both, the cervical, lumbar and sacral regions are very neai'ly typical. The fact that the 1st coccygeal is fused with the sacrum in both is interesting as showing that it is prol)al)ly quite an indifferent occurrence. There eeems to l)e no other way of accounting for these spines, and for others nearly as good, but by admitting a departure from the usual segmentation. Concomitant Variations. — Ha\'ing discussed most of the variations, considered separately, we have now to consider the relation of a variation at one part of a column to a variation at another part. Allusion, indeed, has been made to the effect of a variation in one vertebra on those in the immediate neighborhood, but now we are to consider distant ones. This brmgs us to the central point in the discussion of Rosenberg's theory. It has been remarked that he has admitted that it would be natural to expect some relation between the condition of the spine at one end of the thoi-ax and that at the other, but that such a relation is not to be found. Thus if the undeveloped condition of the 1st thoracic rib is a step towards the future, it would be reasonable to expect in the same spine a corresponding advance below the tliorax. Conversely, if there is an archaic condi- tion below the thorax there should be an analagous condition above it. While there are cases that fulfil these conditions, they are quite lost in the multitude which do not, and which even present contradictory conditions at the opposite ends of the spine, being retro- gressive at one end and progressive at the other. Let us take first the ten complete spines of this series with cervical ribs (including 308 THOMAS DWIGHT ON H-3) . In no case is there an increase in number of the praesacrals, which should be expected if this were an archaic manifestation. In half the cases the number of prae- sacrals is nonnal, in three the last is partially sacralized, and in two, the most perfect cases (267 and 202), there is a praesacral too few. Turning to the literature of cervical ribs, as given by Gruber to 1869 and continued by Pilling to 1894, I find but a single case of unmistakable cervical rib with an increase in the number of praesacral vertebrae, that of Leveling (l787) . Unfortmiately in most cases the vertebral formula is not given ; still in many it is reported normal, and in a few reduced. To this case should perhaps be added the two cases of Leboucq, in which there was an additional cer\acal vertebra with a cer\dcal rib on the 8th, and the case reported by Lane, already mentioned. Above aU there is Rosenberg's spine with 26 praesacrals and 15 ribs, the first being a cer\ical one. This spine, indeed, is a most satisfactory one from Rosenberg's point of view ; Init, admit- ting its authenticity, it stands alone ; the overwhelming mass of observation is just the other way. Thus there are two spines, Levehng's and Rosenberg's, with cervical ribs and an increase of praesacral vertebrae not in the cervical region. On the other hand there are several instances of reduction of the number of praesacrals, and this occurs with the most perfect specimens of cervical ribs ; so that while the upper part of the spine is archaic, the number of praesacrals is diminished, which is thought to be a progressive feature. Turning now to rudimentary 1st ribs: in G-22, which is not a perfect case, as the 1st ribs are only small and not rudimentaiy, there is an extra thoracic vertebra ; in A-4, a typical case, there is the same ; in the incomplete specimen 572 there is a record of 6 lumbar vertebrae ; Leboucq describes a case with one praesacral too few, and another with one too many. Here we are confronted by the fact that while the upper part of the spine shows an alleged step towards the future, the lower part shows one towards the past. Surely such a series of diametrical contradictions, both in the cases of cervical ribs and of imperfect 1st thoracic ones, is fatal to a theory, to say nothing of the chfficulty of accounting for the fusion of the atlas and occiput on evolutionary grounds, and ignoring the question whether cei'vical ribs, if archaic, are not too archaic to be taken seriously. It cannot be denied that it is a very serious criticisin on Rosenberg's theory that a tendency at either end of the spine either to revert to the past or to stretch forward to the future may be associated with a tendency at the other of a chrectly opposite signifi- cance. The question then arises whether there is not some explanation that would account for both. Now in several cases in this series, and there are plenty like them in the literature, we see a tendency sometimes for the whole thorax to move forward by cer- vical ribs associated with absence of the last thoracic ones or with their existence in a rudimentai-y condition. We also see cases in which, when the cervical rib on one side is distinctly larger than its fellow, the last rib on that side is either correspondingly smaller NUMERICAL VARIATION IN THE HUMAN SPINE. 309 tliau its follow, or even replaced by a pretty typical transverse process; and these con- comitant variations may extend even further so as to include the sacralization of one side of the last lumbar, or even the absorption of one side of the atlas into the occiput. In the same way we may have on one side the spread of the transverse processes of the lumbar vertebrae so modified that the largest (which is that of the od under normal circum- stances) should be higher on one side than on the other, so as to be three places distant from the last rib and the more sacralized half of the last lumbar. These phenomena have been pointed out and commented on in the description of the spines, so that it is enough here to give the numbers of the spmes in which they occm-.^ Spines 1, 729, 306, H-3, have the thorax moving up practically symmetrically on both sides. A-oO, 349, 202, show the movement on one, or chieiiy on one, side. In G-22 there is something of a tendency for the thorax to move down. In 561 and X there is a tendency to asymmetrical shifting of several regions without the thorax being involved as a whole. How are these thino-s to be accounted for? As to the original cause of the variation I have not the faintest idea, but it is clear that the vertebrae at the jimctiou of regions are particularly variable, and it seems hard to doubt that errors of segmentation may occur. The original error having occurred, there seems to be a tendency in the organism to reproduce the type as nearly as may be under the changed conditions ; to make as nor- mal a series of regions as circumstances will permit ; and that this tendency manifests itself to some extent independently in the two halves of the spine. It is remarkable that the action of this tendency is not limited to the morphology of the particular vertebi'ae, but to some extent maintains the relative size of the several regions. The most striking example of this is in 267 in wliich the 11 thoracic vertebrae are so large as to make that res-ion, iudgino- from the bones alone, even rather lonscer than usual. The Vital PrhuAph. — Early in this paper it was stated that the vital principle was accepted as a factor in biology. Evidently I rely upon it to account both for the normal development and for the tendency to correct as much as may be the results of certain errors in development. Spine 267 is an admirable illustration. First, as to the atlas. The anterior ai'ch is altogether wanting. Its place is supplied by two ligaments passing one from each side of the odontoid to the occipital condyle, by which the safety of the neck is secured. As this arrangement does not allow the freedom of motion of the normal articulation there is a want of union of the sides of the posterior arch, so that to a slight ' The last case of rudimentai-y 1st rib seen at this writing, is tliat of Low (1900). Tliere are 25 praesacral vertebrae, of wliich l:-! are thoracic. The last rib on the side of the rudimentary 1st one is very much larger than its fellow. The last three lumbar vertebrae seem normal, except for some sacralization on one side of the last. It is on the same side as the rudi- mentary rib. There is an extra vertebra in the thorax. 310 THOMAS DWIGHT ON extent each half may move iudependently of the other. As even theu the I'otary motion is probably less than normal, tlie joint between the occiput and the atlas is less cup-shaped and more adapted to a sliding motion than usual. It is interesting to observe a very similar conformation in the sockets for the condyles on the atlas of H-3, which is fused with the atlas. Thus rotary motion is possible to some extent in that joint, and the work of flexion and extension was no doubt in part carried on by the other joints of the cer\'ical vertebrae. To the action of the same cause we must turn for the modification in the length of the thoracic vertebrae, by which 11 more than compensated for the ordinary 12. In the same way is to be explained the mothfications of wliich we have had so many examples, by which an approach to the normal dispositions of regions is so often obtained. Still another instance is furnished by spine 202, in which a cervical rib which ends free has a cartilage shooting out from the manubrium to meet it. Similar cases have been described by Leboucq and others. This shows clearly that the production of the costal arch depends on something more than the over-development of the costal element of the vertebra. It begins at both ends in cases which approach a complete arch. Clearly there is some force acting throughout the organism, not at one point alone, to inaugurate such changes. If Rosenberg's views on the changes of position of the ilium, and the consequent modification of vertebrae according to the position it finally assumes, which we have pro- visionally adopted, be correct, there is the evident need of some explanation of the cause of these modifications. I can see no other than the action of the vital principle. If it be objected that this is only a name to cover our ignorance, then the objection must be made against gravitation, magnetism, etc., for in no case do we know how the force works. We see only results. Apart from other deductions, the following conclusions seem justified. I. Variations occur in two ways: (1) by irregular development of the costal ele- ments at and near the ends of the regions of the spine, and (2) by irregular segmentation through which there are more or fewer vertebrae than normal. II. Variations of both kinds are variations around a mean. It is not impossible that some of them may be reversive ; that any are progressive is mere assertion. III. Assuming the correctness of Rosenberg's studies in ontogenesis, his ^iew may account for some of the variations, but even in these cases something more is needed to explain the concomitant changes. IV. Variation of the costal elements at one end of a region is often associated with variation of an opposite nature of those at the other end. Several regions may be involved, and the two sides may vary independently. NUMERICAL VARIATION IN THE HUMAN SPINE. 311 V. Variations, wliich separately seem either reversive or progressive, generally lose that appearance when the whole spine is considered. VI. After the occurrence of the original error in development there is a tendency for the spine to assume as nearly as possilile its normal disposition and proportions. This, as do also concomitant variations and indeed all development, implies a \dtal principle. I wish to express my sincere thanks to Dr. H. P. Mosher for the great care he has taken with the drawings. The following tables are to enable the reader to find the account of any spine or incomplete specimen that may be referred to in any part of the paper. Spine Page Sitine Pag:e Si»ine I'age 1 249 350 287 729 251 2 259 361 256 764 263 21 254 377 285 A-4 262 24 275 381 207 A-7 282 85 285 478 288 A-30 249 110 265 492 279 A-175 259 141 282 493 266 A-186 264 202 294 504 264 A-219 281 208 268 545 261 D-7 284 257 279 561 255 G-19 247 264 273 567 248 G-22 258 267 290 578 265 H-3 276 297 270 615 246 X 256 306 252 636 247 Y 266 349 278 649 250 Z 274 Incomplete specimens Pag. 132 298 140 300 572 301 725-2 299 1392 299 4767 298 7737-3 297 8590 298 9379-37 299 9395-3 299 9638 298 9639 298 C-1 301 BlBLIOGRAniY. Albrecht, Paul. '84. Sur le.s elfmeuts morphologiques du manubrium du sternum chez les mammiferes. Libre jubilaire pubiie par la Societfi de Medicine, Gand, k Toccasion du 50e anniversaire de sa fondation. P. 157. Bateson, William. '94. Materials for the .study of variation, treated with especial regard to discontinuity in the origin of species. London. 8°. lUus. Baur, G. '91. On intercalation of vertebrae. Journ. of morph., vol. 4, pp. 331-336. '97. Remarks on the question of intercalation of vertebrae. Zool. bull., vol. 1, pp. 41-55. 312 THOMAS DWIGHT ON NUMERICAL VARIATION IN THE HUMAN SPINE. Bolk, LouLs. 1900. Kiirzere Mittheilungen aus dem anatomischen Institut zu Amsterdam. I. Ueber die Persistenz fotaler Former- scheinuiigen bei einem erwachsenen Mamie. II. Ueber eine WirbeLsaule mit nnr .seclLS Halswirbeln. Morph. Jahrb., vol. 29, pp. 78-93, 1 fig., pi. i. Dwight, Thomas. '87. Account of two spines with cervical ribs, one of which has a vertebra suppressed, and absence of the anterior arch of the atlius. Journ. anat. physiol., vol. 21, pp. 539-650, pi. 12. Fol, H. '85. Sur la (jueue de I'embryon humain. Compt. rend. Aca*!. d. sc. Paris, vol. 100, pp. 14fi9-1472. FUrbringer, Max. '79. Zur Lehre von den Umbildnngen der Nervenplexus. Morph. Jahrb., vol. 5, pp. 324-394, pi. 21, 22. Gruber, Wenzel. '69. Ueber die Halsrippen des Menschen, mit vergleichend-anatomischen Bemerkungen. Mem. Acad. Imper. d. Sc. St. Pfitersb, (7), 13, no. 2, 52 pp., 2 pi. Holl, M. '82. Ueber die richtige Deutiuig der Querfortsatze der Leudenwirbel und die Entwickluug der Wirbelsaule des Menschen. Sitzungsber. Akad. Wiss. Wien, matli.-nat. CI, 85, Abth. 3, pp. 181-232, 4 pi. Kohlbrugge, I. H. F. '97. Der Atavismus. Utrecht. Lane, W. Arbutlmot. '84. Cervical and bicipital ribs in man. Guy's Hospital Rep., vol. 42 (N. S., 27), pp. 109-13.3. '85. Sui:erniunerary cervico-dorsal vertebra-bearing ribs, with vertebral and costal asymmetry ; abnormal articulation in a sternum. Journ. anat. physiol., vol. 19, pp. 266-273. Leboucq, H. '96-'98. Recherches sur les variations auatomiques de la premiere cote cliez Thomme. Mem. oour. et mgm. des sav. etrangers, Aca>'ous structure in the test of Crustacea and considered them as organs of general sensibility. In this memoir I describe and figure in a very early stage of T. septcntrlona/is, verital)le tenuous, hair-like processes, to the number of ten or more, radiatinu' from the distal terminations of the first three tulndes formed. Bennnelen (So) suggests that I may have made a mistake in my observations of their displacement by a delicate brash. 1 can assure tliis accomplished naturalist that tiiere was no mistake ahout the observation, thouo;h I a»;ree with him that the hairs can have no relation to the radiating tubules described by King ('70). In my earlier memoir ('71) I figure and 'describe two short ramifications from the end of one tubule, which are probably compandde with the radiating tubules of King and probably with those of Carpenter ('-"iG). In the early stage of Terebratulina, not only is the shell raised in a shallow collar about the external end of the tubule, but ;i yellowish glandular plug is seen from which radiate these delicate hairs. Claparede ("li'-M figures certain papillae on the elytra of Polynoe with cii'ri terminating in liairs, reminding one strongly of the features above described. In tliis connection it may be interesting to state that Davidson ('86-'88) describes a species of Crania from the Permian of England of which he .says in the dorsal shell, " e.xternally the entire surface is closely crowded l)y a multitude of minute, short, hollow, spinulo.se tubercles which produce a granulated aspect." The manner in which the ridges in Terebratulina coincide with the setae may ex])lain the spinous character in certain forms of Productus and other fossil ln';ichiopods ; but in Crania there are lU) setae, and it would be an interestinu' iniiuirv as to the orio'in and function of these hollow, spinulose tubercles. Peduncle. The peduncle is a characteristic featiu'e of the Prachiopoda. though wanting in many Testicardine forms ;uid in Crania. That the early stages of this interesting animal will sliow the presence of this structure, there can l)e no doubt. An examination of the shell of Crania sliows no ti'aces of a pe(hnicidar foramen, and it is probabk' that in the young stage the peduncle will be found projecting l)etweeu the shells, as in the Litujulidae. It will Ijc interesting to observe the attitude of the terminal end of the intestine in relati(jn to the peduncle, for in Crania alone, among the braciiiopods, the intestine terminates posteriorly and not at the side, as in Liugula and DiscinLsca. 826 EDWARD S. MORSE ON The variation in the size of the pedimcle and tlie mobihty of tlie l)od\- upon it. is correlated with the greater or less development of the setae, lu those forms in which the peduncle is prominent, as in Liugula, or endowed with special muscles, as in Disci- nisca, indicating great freedom of movement, the setae are excessively developed. In />. lamellosa, the setae form a dense fringe about the pallium. As the peduncle becomes more aborted, the setae decrease in length and become less numerous, and finally, when we come to those forms which have no peduncle, and in which the lower shell is appressed or attached to its resting place, as in Crania, Cistella, and Thecidium, the setae are entirely al)sent. In tiie voung sta^e of Tereljratulina and Hemithvris, where the bodv lias y-reat freedom of mcnement on the peduncle, the setae are very long, often exceeding the length of the shell. As these forms become larger and have less freedom of motion, the setae become shorter and are less numerous. In forms like Tercbratulina, Magellauia. anil others, where but slight movement of the body is possible, the setae are not crowded and have no power of motion, nor do we find any muscles to animate such movement as in the Lhi(jul'iably been established in furnishing a nidus for diatoms and other foreign growths which they sustain, often in rich abundance, for the benefit of the animal in furnishing, or attracting, a food supply. In all brachiopods, they undoubt- edly act as a sensory apparatus for tactile impressions. The setae in all brachiopods thus far observed are marked by transverse lines, or joints, which are shouldered and whicli indicate successive increments of growth. Even in the almost aborted setae of Dallina the transverse lines are easily detected. Fine par- allel lines also mark these hairs, and their appearance has been happily compared to the stem of an Eqviisetum. In examining the setae of different genera more in detail, we shall find that in the unattached group, LhujuUdae, they are most highly developed. Furthermore, the setae are grouped in definite clusters. On the anterior median line of the animal is a group of setae in which the middle ones are the longest, the setae on each side diminishing rapidly in length. This may be called the median cluster. The setae on each side of this cluster increase gradually or aljruptly in length according to the species, becoming longest at the round angle of tlie shell where the anterior and lateral borders of the shell meet. These stand out at an angle from the medial] line of the body, right and left, and may be called the anterior clusters. Fi-om these clusters on the side, the setae very slowly diminish in length till they reacli that part of the shell where it begins to taper rapidly toward the peduncular end; at this point they immediately become much longer, forming a very sharply defined cluster. These groups may be called the right and left posterior clusters. The setae between the anterior and posterior clusters may be designated as the lateral setae (40: 1). These clusters, with the anterior clusters, are peculiarly active when the creature is crawling over the sand or burrowing into it head foremost. Behind the pos- terior clusters, the setae are less numerous, and toward the j^eduncular end become more filiform, and are often bent and broken. They appear to be functionless and are becoming rudimentary, presenting a condition not unlike that seen in certain Testicardine forms. The proportionate length of the setae, and the outline made by the median and anterior 330 EDWARD S. MORSE ON clusters vary in tlio different species. In L. anatlna, the posterior clusters are not so prominent as in 7y. hpUhtUi and Glottidia. The lateral setae are very short, while the setae of the anterior clusters are very long, the setae rapidly increasing in length from the outside, and ending on the inner side of the cluster with the longest setae. The middle setae of the median cluster are about half the length of the longest setae of the anterior cluster, the setae becoming shortei- on each side in such proportion as to form a rounded outline for the cluster (40: KJ). In L. lepichihi (40: <'>) the median cluster does not assume the rounded outline seen in that of L. anathuc, it forms a pointed cluster and the cluster is as long as, if not longer than, the anterior cluster, and this difference may be related to the tube-forming function of the setae already described and figured (40: V2) . The anterior clusters have their longest setae in the middle of the cluster and not on their inner sides as in L. anatina. The clusters in Glottidia are vei'y much like those of L. lejndula, except that the median cluster is much shorter than the anterior clusters. These vai'ious clusters both in Glottidia and L. lepidula are very prominent and sharply defined. In Glottidia, the minute longitudinal markings of the setae remind one of the ruled gratings for spectroscopic work, and it is this feature which causes the clear steel-gray appearance and at times an iridescence when the setae arc swinging back and forth. The transverse markings of an ordinary seta number 158, and these are separated from one another the width of the seta. In L. lepidnla, the setae ai'e colored a light brown within the pallium, and this color extends some chstauce beyond the edge of the shell, as shown in 44: 1. After watching Glottidia and L. lejndula in their activities, at one time crawling slowly over the sand with the setae swinging in rhythmical motion, or when half buried in the sand, with the lateral setae standing at right angles to the edge of the shell and forming the side partitions already described, and, in the case of L. Icpiduld, forming the setal tubes, one is prepared to understand the varied functions of the complex system of muscle fibres which endow the borders of the pallium as depicted by Blochmann (:01). In the young of Diacinisca stella the anterior setae are nearly three times as long as the diameter of the shell ; the length of the setae thminishes rapidly toward the posterior end where they are very short (61 : 3) . In the mature D. stella, the setae are quite short and crowded together, though they are slightly longer in front than those springing from the posterior border. The setae in D. stella vary greatly in character; some have a brush of minute hairs, others have setellae between the joints which are more widely separated than those of Lingula, and in others still the setellae are extremely minute (44: 3). The setae are densely covered with various forms of minute growth. On the setae of Lingula and Glottidia, no trace of foreign growth is seen, as their functional activity prevents any LIVING BRACrilOPODA. 331 adhesion of tliis matter. In D. lamellosa a rich growth of organisms abounds, and even in young Terebratulina the inactivity of the setae permits this accumulation of foreign substances. In the mature D. himdlosa tlie setae are rich light brown in color ; they are closely crowded together about the entire periphery of the pallium, thinigh not so thickly massed on the posterior border and being in this region only -^t the length of the shell, while on the anterior border they attain the length of the shell (49: •!) . They are iiiostly l)a,rbed, rarely smootli (44: 7). In the young of I). JaineUosa, the setae are much longer than tlie diameter of the shell, becoming sliorter on the posterior border or quite absent (61: 5, 9, 11, VI). Some are furnished with sliort bristles on the sides of the setae, and these setae are thicker and are not so deeply Ijuried in the pallium as the more deli- cate setae which are furnished with long hair-like setellae (44: 9) and in rare instances more delicate setellae branching from these (44: •'>)• The setellae are bent at their junc- tion with the setae, and those nearest the border of the pallium are bent backward. Joubin ('86) figiu'es the setellae before they have issued from the pallium, as pointing in the same direction as the growth of the setae. This attitude would be manifestly impossible unless a sheath, enclosing the whole seta with its branches, moved outward in its growth from the follicle. On the contrary, the setellae trail backward in the growth of the seta and, after issuing from the Ijorder of the pallium, preserve for some time the bent attitude they had while immersed in the pallium (44: 8). Blochmann has figured their appearance correctly. In T. i.s';7- tacea the brachia may be partly uncoiled within the pallial chamber as shown in 46: 16, and it would not l)e surprising if, under certain conditions, the lirachia might uncoil and be protruded as shown iu the alcoholic specimens above mentioned. The free collar about the mouth is very mobile (46: 17, 17«)? and just above the mouth a white, fibrous yoke is seen connecting the base of the In-achia. A rounded area which appears on each side of this yoke indicates the great sinus connecting the brachia with the coelomic cavity. The cirri, though apparently rigid, do move with great freedom. The general appearance, as they spring in double and alternating series from the brachium, is shown iu 46: 18. The margin from which they spring is scalloped, and tiie cii-ri rise from the crests of these scallops. Scattered muscle fibres are detected running to the scalloped margin, and parallel with this margin are other bands of muscle filn-es. LIVING BRACHIOPODA. Cirri. 335 The cirri of the U,igvMdae thus far observed are tubuhar to their tips and the blood circulates freely within this cavity, as shown in a cirrus of Glottidia (46: 2) . The cirri are strongly cihated and the ciliary movements must be vigorous to cause the rapid currents of water which steadily pass in and out of the pallial chamljcr (40: 1-2). The cirrus of Glotticha is marked by irregular transverse wrinkles which are repeated on the Uning membrane of the cavity within, giving it the appearance of a rude sort of annula- tion The walls of the cirrus are thick and the tubular cavity within has nearly the same diameter as the thickness of the wall. In L. anatina, the cirri are coarsely and densely ciliated. In all Ecardine brachiopods the cirri are colored in various parts. In Glottidia, the tip of the cirrus has a light brown tinge (39: 7) . In L. hpidala, it is brown on the out- side from the base to a third of its length; near the tip a brown tint is seen on the inner surface (39:2; 45:15; 46:5). In L. anatina, the sides of the cirrus are brown. The structure of the cirrus in Discinisca seems more complex than that of the Lmguhdae. The cirri in the Testicardine group are usually white or yellowish, though Schulgin ('84) fio-ures the cirri of CisteUa kowalemhn as yellowish red, and these he represents as pro- ie°ctino- shcditly beyond the borders of the shell. He furthermore adds that he never saw a particle of blood enter them. The cirri of many Testicardine forms have already been figured and described, notably by Bemmelen ('83), who has, with infinite pains, given a most exhaustive series of drawings and descriptions illustrating the histology of a number of brachiopods. At 46 ■ IS./ is represented a portion of a cirrus much enlarged of //. psdtacea. in dis- section, it appears almost cartilaginous, so stiff and rigid does it seem. The ciliated epithelium is easily detached from the surface. A narrow inner tube is found m which the blood freely circulates ; outside this tube is a sheath containing encirchng muscle fibres, and outside of all is the firm cartilaginous-appearing substance which supports the loosely connected ciliated epithelium. Schuluin, in the paper above referred to, described the cirrus of CisteUa as having a somewhat firm exterior, which is elastic, and said that when the cirrus is bent by muscular contraction, the elasticity of this substance brings it back to position again. It has occurred to me that the cirrus of //. psittacea may act in the same way. There are no spiculae in the cirri, as in Terebratulina and allied forms, and though more complex m structure than the cirri of the LlnguUdae, they bear a nearer relation to these than to those of the Testicardines. Hemithyris in other respects also approaches the Ecardine group. 336 EDWARD S. MORSE ON Hancock ('-39) states that in tlie brachium he found 4,000 ch-ri. Wliether this number was based on a definite count or an estimate is not known. In the species studied in the St. Lawrence, and which has alAvays been recognized as identical with the H. psittacea of Europe, I counted only 450 cirri on the brachium of a fully matured speci- men. This leads me to believe that Hancock's figure i.s the result of a misprint and that the number should read 400 and not 4,000. Muscles. The muscles of many forms of Brachiopoda have been often figured and described, and a number of investigators have given their own interpretation of the functions of these muscles with a terminology of their own, differing, of course, from that of their predecessors. Hancock's names for the muscles of Lingula were \dtiated because he argued from analogy that since tlie Testicardine forms liad an interlocking device to prevent the lateral displacement of- the shells, in Lingula, there being no such interlocking device in tlie shells, the muscles were so arranged as to accomplish the same purpose" He says, " Indeed the attachments of the various muscles [in Lingula] are so distributed around the margin of the peri^dsceral chamber that transverse, longitudinal and diagonal movements are alike guarded against. And perhaps their true functions are^best understood when thus considered in co-operation ; it is then seen that they form a com- plicated complementary system fur the purpose of assisting in adductiug the valves, their various points of attachment and cUfferent inchnations being so arranged, that, in'what- ever state of action they may happen to )je, they will always keep the valves steadily and accurately opposed to each other." In commenting on the names given hy prcA-ious investigators to the muscles of Lingula, Hancock says, " It is necessary to alter "the.se later epithets as they imply what appears to be a false theory, namely : the slidino- of the valves over each other." Owen ('35), to whose terminology he particularly refers and upon which he animadverts, in describing the various muscles of Lingula, says, "The arrange- ments of these powerful adductors are such as to effect the sliding movements of the valves on each other, beside closing the shell, and to compress and variously affect the interposed ^dscera and visceral lacunae with their contained sinuses," and I may add that no words could express more correctly the precise work accomphshed bv these muscles, for they cause not only the '' transverse, longitudinal and diagonal movements" of the' sheU, and that in a more vigorous way than even Owen dreamed of, Init tliey do com- press and variously affect the interspersed viscera and tlie circulation, as xvill he seen farther on. LIVING BRACHIOPODA. 337 In a short paper in the American journal of science and arts in 1870, 1 first figured the appearance of the oscillatory and sliding movements of the dorsal valves in Glottidia, thouc^h Carl Semper ('62, '64) had described this feature eight years before. Blochmann, who°has recognized this mobility of the dorsal shell, was prepared to understand the functions of the obUque muscles, and his nomenclature is so simple and so apt that I luue adopted his names in this memoir. There is but little to add to what Blochmann has given of the musculature of L. wmtina, and that is, that the anterior occlusor muscle should be recognized as containing two elements, at least, if not two distmct muscles, to which the names that he has applied to similar muscles in Dlscbdsca kmieUosa should be civen namely: occlusor anterior 1 and 2. He certainly shows the two elements nr his figures but calls them simply occlusor anterior. In L. lepidula, these two muscles vary in the appearance of the muscular bundles at their points of attachment and they vary m their color also (47 : 6) . I did not observe the separation of these muscles in Glottidia, on - account of the opacity of the shell, but tliere is no doubt of their separation. It remains for me to describe the nuiscles of Glottidia and of L. JepkMa and to point out certain differences between them. In Glottidia, the oblique muscles are more dehcate than in L. lepidrOa. The terminations of the muscles in Glottidia at then- pomts of attachment vary shghtly in color; the ol,liquus interuus is greenish, the obhquus mechus is white, while the obhquus externus is silvery in appearance. The obhquus medius has its dorsal attachment posterior to that of the obli. From the above observations on the circu- lation of the blood in the LhicjuUdae, it is certain that a propellent organ or heart is wanting in these animals. Ill D. Jnmellosa, the body cavity is somewhat quadrangular in sliape, occupying the posterior half of the boundaries made by the orbicular shell. It is rounded behind, dilating somewhat toward the anterior portion on a line with the stomachal glands, then narrowing in line with the anterior occlusors, which stand obli({ue to tlie median line, and terminating in front with a median depi'ession just behind the head whicli })rojects considerably (49: 1). From the shoulder on each side of this anterior depression spring the anterior sinuses and on tlie side where the coelomic wall slightly projects, spring the lateral sinuses. The anterior sinus follows very near the median line and terminates in two .slender branches. A short distance from its origin a hrancli turns abruptly backward and recurves upon itself; this sinus sends a number of hraiiclies toward the anterior portion of the pallium. The lateral sinus has two branches, one turning abruptly forward and the other abruptly backward. These branches supply three fourths of the pallial area with its lacunae ; they divide and subdivide into minute ramifications which cover every portion of the pallium. The pallium is remarkably rich in these minute ramifying lacunae, and, so far as these were traced, the central ciliated ridge was observed in all of them. Blochmanii, in his drawings, shows a narrow dark center to these ciliary ridges and in every case represents a slight interspace where they branch off from the central one, and this follows down to the minute branches. In D. stella the pallium is bordered with dark brown and at the base of the setigerous follicles a distinct red line is observed. At the base of the setae, which are deeply inserted, a sinus runs parallel to the pallial border. This .sinus has slight swellings at uniform short intervals, and within each swelling was observed an elongated nucleus which 1 supposed to be a ciliary fold. The radiating pallial sinuses were not observed (44: 4, y) . 3bb EDWARD S. MORSE ON In T. coreanica (57: 11) the pallia! membrane has a strong reddish-salmon color derived from the color of the shell. The main sinus in the dorsal pallium runs parallel to the outer lateral border of the shell and nearly midway between the outer border anc\ the median line. It sends out twelve lacunae which subdivide once or twice before reaching; the border of the pallium. The ventral pallium sends two sinuses running irregularly forward, the inner one, near the median line, sending its branches to the anterior border, the outer sinus covering the remaining surface of the pallium with a less number of branching lacunae. The two sinuses are connected witli a single lacune near their origin. The terminal lacunae are shown in 57: ll'<, and in these may be seen the middle ridges of ciliated epithelium. The sinuses and lacunae, when filled with eggs, are dark purple in color, as shown in 39: 14. The sinuses and lacunae in T. transversa seem to have the same disposition in the pallium as in T. coreanica. In closing the description of the pallium I must again emphasize the fact that not only the sinuses and lacunae of the pallium support the ciliary ridges which divide and subdivide with the ramifications of the lacunae, but the minute lacunae in the nephro- stome of Lingula, the papillary prominences in the nephrostome of Terebratulina, and these channels wherever seen, present the same ciliary ridges. So far as I have observed, the circulation of the blood is due to ciliary action and to the agency of this action alone ; as in other groups, however, the contraction of the body must cause volumes of l)lood to siu'ge back and forth.^ Blood Corpuscles. In the blood of Glottiiha (54: 3), are seen three kinds of corpuscles. These consist first : of long, oval, and fusiform bodies ranging from simple oval botlies with pointed ends to elongate forms with one or two swellings, and in a few cases showing a bifurcation at one end; these are amoeboid and bend and turn in rounding the corners of a lacune or in crowding through some narrow opening ; second : small, rovmded corpuscles with a constriction in the centre resembling in appearance a partially collapsed rubber ball ; these are nearly uniform in size and are much smaller ; third : round or oval bodies showing a slightly granulated structure and varying greatly in size ; these are probably ova. The blood is rosy in color and causes the rosy hue of the pallium and peduncle. In L. lejykhila (54: 4) the corpuscles resemble very closely those found in Glottidia ; the ' In 1801, Maodonalil, in the Transactions of the Linnean society ('(!!) announced the discovery "of a determinate circu- lation of spherical, and violet tinted corpuscles in all the ramifications of the pallial sinuses, not dependent on the contractions of the pallial cavity, but upon the undulations of a ciliary linini?." This paper of iMacdonald's lias been singularly overlooked by English and continental workers on the subject. LIVING BRACIIIOrODA. 357 elongate, fusiform bodies are more slender and without swellings; the round corpuscles have precisely the same appearance ; the third kind was not present. In L. anatina, (54: 5) the l)lood is a pale crimson lake, or violet, in color. The various corpuscles have often been figured and described, yet it will be of interest to recall their appearance in life. The long, fusiform bodies show the processes of longitudinal divi.sion; the round corpuscles are like those of Glottidia; a few roimd bodies were seen with granulated structure. The filiform body seen in the figure is probably foreign. In the alcoholic D. lamelloi represents in 31. Jiace-scen-s, four accessory vesicles, two dorsal and two ventral, corre- sponding to the pallial sinuses, yet in this species there are only two nephridia. In H. 2)sittacea, there are four nephridia and also four accessory vesicles. In T. sejjientrionalis there are four pallial sinuses, yet only two accessory vesicles. It is somewhat singular that a careful study of Lingula, Glottidia, and Discinisca failed to reveal the presence of any organ corresponding to the " heart of Hancock " or to the accessory hearts, though the nephricUa are conspicuous organs, as they are in all brachiopods ; on the otlier hand there is no feature more constant than the pallial sinuses, yet with this constancy in structure we find the "heart of Hancock" and the accessory heart, with few exceptions in the Testicardines only. In other words, in those brachiopods in whicli the coelomic cavity is contracted to the smallest space and the greater mass of the genitalia arise in the pallial sinuses, the central and accessory vesicles are present, while in the Ecardine forms, in which the coelomic cavity is capacious and the genitalia are confined to this cavity alone, these vesicles are absent. I think, therefore, that the accessory vesicles at least, may with reason be considered under genitalia and not under the circulatory apparatus. Nephridia. The paired oviducts in Brachiopoda are so identical in form, attachment, and function with similar organs in the chaetopod worms that I formerly designated them segmental organs from the name first given by Williams ('51), to the oviducts of annelids. LIVING BKACIIIOPODA. 361 Tliis iiiiuu' wiis adopted by Claparede in liis remarkable researches on tlie annelids of the Bay of Naples. So absolutely identical are these organs in details of structure, attach- ments within, their associated parts and external openings, with those of certain chaetopod worms that the description of these parts might be taken from Claparede with hardly the alteration of a single word. The wide divergence in the form of these organs in worms is. with the exception of the length and convolution of the tube, paralleled in the Brachiopoda, as nuiy be seen by an examination of the figures given in plates 54, 55, 56. Gegenbaur ('7S) properly objected to the name segmental organs as other organs and parts are repeated segmentally. There is, however, no end of inappropriate names for organs and groups in tlie animal kingdom. What more ridiculous than the name Mollusca or more preposterous than the name Brachiopoda as applied by Cuvier, based on false homologies. Nevertheless as these organs are now recognized imder the name nephridia in worms and other divisions of the animal kingdom, it is well to apply the same name to these parts in the Brachiopoda. It is not yet established that these parts are renal in their nature. One thing, however' is certain and that is, that they are plainly oviducts, and this would be a far more appropriate name for them. In a general way, it may be stated that, with the exception of Hemithyris which has two pairs of lU'pinidia, the genera thus far oltserved have but a single pair. In the Lingulidae, the nephridia are (juite constant in their form and position, while those of Discinisca and Crania are quite different in form. Among the Testicardiues, the neplu'idia vary greatly in the dift'erent genera. In T. coreanica, the tube is abruptly bent upon itself. In T. septentrionaJls, the nephrostome stands at a slight angle from the tube. In DalUna (jrayii, the neplu-ostomes are close together and the tubes are straight, the nephrostome much exceeding, in diameter, the tube. In Hemithyris, the nephridia are quite wide apart, and the tube is short, and wider in diameter than the nephrostome. In all, however, the nephrostome is crenulated .and strongly ciliated, and in all, with the exception of Discinisca and Crania, a more or less sharp constriction separates the nephrostome from the body of the nephridium, and in all, with the exception of Discinisca, the body of the nephridium is thickened, glandular and has a pronounced color. In Glottidia, it is a rich dark orange ; in L. cuudina, it is marked by dark, maroon lines; in Tereln-atulina, it is a yellowish brown ; in Ballina (jrayli, it is a rich, rose color streaked with darker areas. The position of the nephridia in the Limjnlldae has been so well defined by authors that it is only necessary to call attention to their appearance in life. In Glottidia, (54; 9), the body of the nephridium lies parallel to the lateral body wall, the central axis of the nephrostome standing at nearly right angles to the longitudinal axis of the organ. The nephrostome is turned closely to the body wall. It is rather deep, slightly flaring at the .']G2 EDWARD S. MOUSE ON rim iiiid foliated williiii. It is lield lirmly to tlic hody wall l)y the ilio-parictal liaiid (47; !)• This hand is dividcil iuto several strands, oiie nf whicli, rather wide, jmsses directly hehind the nephrostome and is attached to tlie hody wall; another, very nai-row, passes ohliquely backward to the hody wall, and still another, a very narrow one, passes ohliquely backward toward the median line. The appearance of the inner portion of the nephrostome is shown iu 54: Ki. The blood in active circulation is seen rushing through the various lacunae which cover the surface of the nephnjstome. The wdiole oro-an is highly vascular throughout and it would seem that the endothelial lining of the coelomic cavity ensheathed every organ within. The body of the nephridium is a rich orano-e color, and in L. Icji'iiliihi the cohir is so persistent that after a lapse of twenty years, in alcohol, tlie coloi- through the shell appears just as bright. The body of the ne[)hiidium in (ilottidia has an oblong, slightly ovate form, narrowing (|uite rapidly to its outer termination; it has a few wide longitudinal markings which probably indicate folds within. In L. lepldahi (54: 11, vi, i;j), the nephridia occupy precisely the same position as in Glottidia. The nephro.stoaie is s )mewliat different; iu shape it is like a cup with the rim sharply reflected, and just below tiie rim a deep constriction, and then the wall rounds out again to taper rapidly to the body of the nephridium whicli it joins at nearly right angles to its axis (48: 4, S). The side of the nephrostome next to tlie coelomic wall is so closely adherent to it that the wall itself forms i)art of the border of the nephrostome (see particularly, 54: 12, 13). In Glottidia and />. (HKit'ina, the rim of the nephrostome is entire, while in L. hpidula the rim merges with the body wall. The folds within the nephrostome (54: 14, 14rt) are in the form of loops giviug the appearance of a deep fluting. The folds are strongly ciliated and the ciliary action is vigorous. No current was seen to pass through the uephridium ; corpuscles were drawn into the nephrostome only to be whirled out again. Here is an evidence that iu some way the animal controls the discharge of matter tlu'ough it. In Terebratulina, I have followed au egg from its release from the pallial sinus to its entrance into the nephrostome and linal discharge at the exterior opening (58 : 4) . There are a few branching lacunae ou the walls of the nephridium which is a rich, dark orange, and the color is so pronounced as to show through the shells. The tube follows along the side of the coelomic wall aud passing through it obliquely, opens on the anterior wall. The external openings appear as simple slits (48: 4,*^)- The nephridia of L. anathia are not unlike those of Glottidia. The body is thick, wide, flattened, aud glandular ; the nephrostomes seem a little more closely appressed to the coelomic wall and the folds converge slightly to the anterior end, as such lines would ou an oblong and tapering body. The folds are finer and run parallel to the iuuer incurving outline of the nephridium. These folds are a rich maroon color. A reference to 55 : 1 will better explain these features. The nephrostome is not so deep as in Glottidia LIVING BKACHIOPODA. 363 or in L. ItphJuln hut is more fliiring aiul tho riiu is slightly undulating. The body of the nephridiuni is held to the perivisceral wall by a narrow band immediately behind the obliquus internus, and this may ))e a continuation of the ilio-parietal band. A greatly enlarged view of the nephrostome and a portion of the nephridiuni is given in 55 : 2. It is seen to be highly vascular ; large branching lacunae run from the base of the nepln-ostome to the periphery ; these divide, and just before reaching the rim they appear, in the drawing, to be recurved. This appearance is due to the incurving edge of the flaring rim which is very thin and transparent. The lacunae have a delicate light brown tint. The ciliated ridge is seen running in tlie centre of each lacune and tlie blood follows up and down the branches, the current being divided by this ridge. In the undetermined species of Lingida, the neplirostomes were turned towai-d the perivisceral cavity (40: is). Whether during genital activity the nephrostome has the power of turning in this way, is not known. In D. lamellosa (55: 3) the nephridium, while occupying a position similar to that in the Llmjulidae, is fpiite different in its attitude. The nephrostome is turned towards the coelomic cavity and obliquely toward the dorsal shell. It is wide and flaring with regular radiating folds running from the inside nearly to the periphery. It is held to the lateral body wall by a band which seems continuous with the membrane composing the nephrostome. Tliis flaring mouth connects at once with the tubular portion of the nephridium witliout the usual constriction seen in the nephridia of other forms and there is no glandular eidargement or thickening. The tube tapers gradually to its termination in the anterior wall of the coelomic cavity. These openings are seen externally just below the mouth on each side and about midway between the dorsal and ventral parietes. The external openings stand oblique and incline to each other (55 : 4) . A view from within this wall shows that the tubes follow along the ventral floor of the coelomic cavity and then turn upward along the body wall, piercing the wall obliquely (55:5). Externally the openings are as simple as in L. lepidula. In the early stages of D. lamellosa, the nephridium has a long, narrow neplirostome suggesting somewhat the appearance of the same part in Crania as figured Ijy Joubin, though his figure represents the nephrostome as bifurcated. The edge appears to be minutely fringed and the tube shows a slight enlargement in its course (55 : (j) . The small circle associated with the figure indicates the size of the specimen from which the nephridium was drawn. We have seen in the Liiu/ulidae a constancy in form and position of the nephridia quite in accordance with those resemblances in structure seen in all the parts. In Discinisca, the nephridia ai'e quite unlike those of the Lhujulklae, as is the animal itself. Crania stands quite apart from all in the form of this organ. In the Testicardine Brachiopoda, the nephridia vary from one another quite as much as does the internal structure of the different forms, or the external appearance of their shells. 364 EDWARD S. MORSE ON In T. sepfentrioiiii/is, the uephridia are suspeuded i'roiii the gastro-parietal liaml on t'ach side of the intestine, with the nephrostomes opeinng toward the dorsal shell (56: 2) . This figure represents the right nepliridium with a portion of the intestine and the (hvarirator muscles. The band, by which the nephrostomes are held, stietches across the coelomic chamber and adheres to the intestine as well. In 56: 1, is shcnvn the left nephridinm in profile. The nephrostome is wide, and within, the surface is thrown into a number of irregular folds which on one side gradually mei'ge into pa})illae. Two of these ai-e shown more highly magnified, witliin which may be seen the ciliary ridge (56: -")■ The agaric- like regularity of these folds, as figured by Hancock, in 7'. (■(ipKi-scrpcut'is, is not oljserved in T. scpfciifrionafis, at least in its living state, and I may add also that Hancock represents the nephrostomes as quite close together, while in 7'. sejjtentinoiKtJis they are widely sepa- rated from each other, as may be seen in 60: 1, This peculiarity adds another distinction justifying the separation of the two species. The body of the uephrichum has a rich brown- ish-yellow color (39:9), and is marked by varicose ridges; the surface, more highly magnified, shows very irregular luarkings, transverse to the long diameter of the tube (56:26,2c). Tlie nepliridial tubes viewed in front through the coelomic wall (60: l,"i), run nearly parallel and turning abruptly, pierce the wall and project beyond in tlie foi'm of prominent nipples (56: 7). Dall (71) describes the external openings of the nephi-idia in DalUna Jioridana as teat-shaped with very small orifices. Doubtless in related forms this protuberant end will be found, though in 7'erehratalia coreanlca, as we shall see, it is in the form of a simple slit in the parietes. The appearance of the orifice in the nephri- dium of 7\ septentrlonalk, viewed directly in front, is shown in 56 : C The nipple is nearly circular, the larger tUameter being vertical ; the opening is circular and an indica- tion of a lozenge-shaped escutcheon is seen surrounding the orifice, this appearance arising from muscle fibers which possibly control the orifice. The interior of the opening, as well as the channel within, is strongly ciliated. It will be seen in 56: 1, 2, that a band, or bands, quite separate from the ilio-parietal band, originate at the edge of the nephrostome and run ventrally ; upon this is fomid the accessory vesicle as well as clusters of ova. This is the genital band and is well show^n in 56: 1. In 60: 1, the attitude of the nephridia in relation to the mouth and brachia is shown. In 56 : 4, 5, the appearance of the nephridia in very young specimens is given. The flaring edge of the nephrostome instead of being 1am- ellated has a distinct, thickened rim ; the rim of the nephrostome seems to be interrupted, as if its attachment were Uke that seen in L. lejndula, that is, that the band, or wall to which it is attached, forms part of the boundary of the nephrostome. In T. coreanica, viewed from the dorsal surface (55: 8), the nephrostomes open obliquely backward. The inner surface is marked by thin, sharp, radiating folds which in appearance suggest the actinoid coral, Fungia (55: 9). The folds are vertically marked or plicated. A sHght constriction LIVING BRACIIIOPODA. 365 is seen just below the nephrostome ; it then widens into a thick body and continuing for half the entire length of the nephridium turns abruptly upon itself, tapers slightly, and pierces the anterior wall obliqviely, ending in a wide, simple opening more nearly resembling the exterior openings in L. lejyidida or Discinisca, and in no way resembling Terebratulina (55: s) . At 55 : 7, is another drawing showing the attitude of the uephridia in relation to the Ijoily. In DalVuia (jrayii, the nephrostomes are united by a band and are so close together as to be almost in contact (56: 8) . The plane of the nephrostome is only slightly inclined to the longitudinal axis of the nephridium, which is straight and tapers only slightly to the exterior opening, which is very wide and simple. A deep constriction is seen on the outer side of the nephridium. The rim of the nephrostome is thrown into deep crenulations (56: 9). The nephridium is rose color with deeper longitudinal markings (39: 8). The uephridia of II. j^sittacea are quite unlike those of other genera here described, the nephrostomes alone excepted, which bear some resemblance to those of Glottidia. Instead of a long, tapering body with narrow external opening, it is only twice as long as broad and there is only the slightest tapering to the external opening. In the other forms here studied, with the exception of the Lm(/ulldae, the diameter of the nephrostome far exceeds that of the body. In Hemithyris, in one example, the diameter of the nephrostome is the same as that of the body, in another it is narrower than the body (55 ; 10, ll) . As Hemithyris has two pairs of uephridia, my two sketches proljably represent one of each pair, a point I did not make clear at the time of observation. The axis of the nephrostome is at a slight angle to that of the body, is slightly flaring, and the rim is thrown into deep folds which extend within and are strongly ciliated. A sharp constriction marks the junction of the nephrostome with the body of the nephridium which is short and broad. The surface is marked by a few deep, irregular and anastomosing folds ; these folds mark the boiuidaries of the lacunae in which an active circulation is seen ; 55: lOn shows a much enlarged view of the edge of the nephrostome and 55: 11« one of the anastomosing folds of the nephridium, greatly enlarged. The marked difference in the form of the external mouths will be noticed ; the "heart of Hancock," as well as certain masses which are probably ova, ma}^ be seen attached to the genital band. Genital Products. In Glotti(Ua, the masses of eggs lill the perivisceral cavity in compact clusters. A transverse section through the intestine shows a ventral mesentery as thick as the walls of the intestine, an inner vascular space is defined, branches are given off to the right ami left, and these send out other bands from wliich the gonads spring. In these masses to be developed into ova, every stage is seen from the small cell to the distinctly nucleated egg ?M EDWARD S. MORSE ON (57: r>, 5rt). The egg lias a radially striated cell membrane, not the zona radlata of embryologists (57: S/;). I have observed at the same period, individuals with the body cavity filled with yellow masses, easily distinguished by the unaided eye as ova, while other individuals were equally filled with white sperm masses. The spermaries form large irregu- lar bunches springing from the genital band ; they consist of agglomerations of sperm cells and the spermatozoa are detached in groups (57 : 2, •2a) . The irregular shape of the stom- achal glands, as well as of the ovarian masses is well shown in 57: 1, while 57: la ami 1// show the appearance of the two masses respectively. In L. lepUlula, the ova are in rounded clusters, a clear interspace showing at the end of each egg (57: 4). In L. (hkiIiiki the masses recognized as testes were lobulated, these lobules numbering seven or iiioie in a group (57: :!) • I'l'^' whole mass was white in color, differing in this respect from the ova. Each lobule was filled with minute, round cells. In another drawing of L. )• Adult individuals were filled to repletion with eggs, and in separating the animal from the rock, eggs escaped in profusion. In T. septentrionalis, the eggs are spermaceti- white in color, opaque, and resemble a fine white powder when deposited. The eggs are thrown out of the pallial cavity and accumulate in piles in front of the animal as well as hang in festoons from the setae. In some instances the eggs were active on the day of their discharge and moved away Ijy the action of the cilia that encix'cle them ; in other instances the eggs did not move away for three da^-s. At 58 : 1 is repre- sented an adult individual in the act of ovipositing. Eggs were found in abundance in individuals measuring only 5 nun. in length and were found in equal abundance in all sizes LIVmG BKACIIIOPODA. 3G7 up to the mature form. These eggs were apparently ripe and ready to be discharged ; the dates upon which the animals were found with eggs in this condition were May 31, June 2(J, July 12, and August 29. An examination of hundreds of adult individuals revealed the fact that in some, the sinuses were entirely free from eggs, while in others they were packed to repletion. In many, what appeared to be corpora Jufea were observed. The appearance of the eggs in the lacunae is shown in 58: 2,3,4,6. As previously described, the eggs have been distinctly and repeatedly traced from their dehiscence and escape from the pallial lacunae into the coelomic cavity, their entrance into the nephrostome, their passage, one by one. through the nephridium to tlieir final discharge from the nipple-like exterior openings into the pallial chamljer (58: 4). Eggs are also found attached to the genital bands and hanging free in the coelomic cavity (56: 1,3). The eggs are of all sizes as shown in 58: 5, in which a cluster of eggs is represented attached to the genital band. In T. corccni'ica (57: 1 1 ), the pallial sinuses and lacunae when filled with eggs, are deep purple in color (39: 14). Tlie eggs are fouud in clusters composed of leaf-like processes in radial arrangement (57: 13). The clusters were irregularly oval in shape and varied in size (57: VI)- In 57: 1:">, is shown the appearance of one of the i-ailial segments, each leaf holding one or two rows of egg.s, with four or five eggs in a row. Tlicse leaves were slightly folded in their long diame- ters, the distal edges rounded like a carpenter's gouge. With transmitted light, the leaves were light purple in color, their outer edges tipped with light ^yellowish-brown, while the eggs were light pink in cohu' (39: 13). There were from twenty to twenty-four rows of leaves in each clustei-. A side view of one of these masses presents an imbri- cated appearance as shown in 57: 14. Claparede ('09) figures a group of ovaries in a chaetopod annelid, Pnchi/dri/ns rcmi/osus, which suggests a similar feature in the egg clusters. The arrangement of the egg clusters in 7'. corcanica is so far uni<[ue among the Brachiopoda. Testes. The long disputed question as to whether the sexes are separate or united in the individual is still a debatable one. That the male and female sexual products arise from the siime parts is unquestionaljle, that they do not arise at the same time in one individ- ual, at least in Terebratulina, is, according to my observations, equally certain. I am strongly inclined to believe that in tlie Testicardines, as well as in the Ecardines, the sexes are separate, yet in Terebratulina I cannot positively aver that an individual filled with clusters of spermatozoa, may not at another time be found with eggs. I have not been able to detect any differences, external or internal, which would suggest sexual variation. 368 EDWARD S. MORSE ON Sclmlgin found only females in Cistella; Kowalevski, however, states that he found a number of males, but Schulgin asserts that the organs found by Kowalevski preclude all possibility of hermaphroditism. In T. aeptentrlonalls, the spermaries are found in the lacunae of the pallium, every portion being filled with this substance (58: 11). When the spermaries arise from the genital bands upon which is found the accessory "heart of Hancock," they appear in the form of a cluster of long threads converging to a common centre of attachment, either upon the accessory heart or in its very immedi- ate vicinity. These threads to the number of hundreds form a rounded tuft-like mass twice the diameter of the nephridium at its junction with the nephrostome. The relation of this spermary tuft to the nephridium is shown at 58: 7. These threads have a knob-like glandular tip colored a deep reddish-yellow (39: 10, also 58: 9,10). Just below this glandular tip is a fusiform mass of cells which tapers gradually and occupies one fourth the length of the thread ; these cells are masses of spermatozoa attached by their heads. The threads are a proliferation from the genital band identical with what was seen in D. lameUosa. The spaces between these threads are filled with a granular protoplasmic mass (58: s) . In some instances the spermary masses are not cylindrically fusiform. This appearance is due to the separation of clusters of spermatozoa from the mass. The spermary threads enlarge at their ends and are sometimes bent. No eggs were found in specimens bearing these spermary tufts. In specimens in which the pallial lacunae were filled with eggs, the genital l)iinds were also found supporting clusters of eggs; so in individuals in which the spermary tufts were present, the pallial lacunae were also packed with spermatozoa, the little reddish-yellow cells being inter- spersed in the mass (58: 11). The clusters of spermary threads 1 have found only in Terebratuliua. Where should we look for a similar structure in other groups of the animal kingdom? Lang ('!)G) describes the genitalia of worms as cellular thickenings, sometimes massive knobs, or tufts of strands. Gegenbaur, in his "Elements," in describ- ing the form elements of tlie sperm in echinoderms, says that they are very generally filamentous structures provided with a small head. The testes of Lumbiicus, acct)r(ling to Bloomfield ('SO) arise in pairs on each side of a median line, and these start from a mem- brane much as they do in the Testicardines. There are two pairs and each cell of the testis itself is the source of many spermatozoa. He applies the name spermatospore to the constituent cell of the testis. The spermatoblasts, as a rule, stand out like buds from the cells which generate them. "When the spermatoljlasts have reached a suitable size the coat of protoplasm, which has been enveloping the nucleus, begins in each case to collect a small v\\\) or knob-like mass at the distal end." This description, as I shall presently show is certainly like the granular appearance seen on the accessory vesicles of Terebratuliua during genital activity. It may Ije ol)served that tliese l)odies described hy LIVING BRACHIOPODA. 369 Bloomfield in Liimbricus arise in close proximity to the nephrostomes. Beddard ('89) also shows that in Acanthodrilus annecteus, the testes are in close proximity to the inner mouths ot" the nephridia. From these descriptions I am led to believe that it is among the chaetopod worms we are to look for structures similar to what has just been described in Terebratulina. Accessory Hearts. These curious organs have already been fully described by authors and have been briefly alluded to here in connection with associated parts. It is left for me only to describe their appearance in life. We have found that they really occur on separate strands which are not aligned with the ilio-parietal band. I expressed the conviction ('73b) that these organs did not be.ar Hancock's interpretation, and that they properly belong to the genital system and not, as stated by him, to the circulatory system. Subsequent studies of these parts in Terebratulina and Terel)ratalia have only strengthened me in this con- viction; yet precisely what part they play in this role I am at a, loss to say. The form and size of this vesicle vary more or less in every individual, as may be judged by an examination of plate 59, which is devoted to a representation of its appearance in T. sej)- tentrioiudis and 7'. coremiica. Whether the animal be charged with ova or spermatozoa, the vesicle is always present. Sometimes there are two or more of these vesicles in close proximity, and this duplicature has been noted by Hancock. It would seem that if this organ functioned as a heart, there ought to be some constancy about it in form and size. In some individuals the vesicle has a long peduncular attachment and is testicvdar in shape (59: 4,7). In a careful study of a number of these vesicles, there was found no cavity within, and in no case was there seen any vascular connection witli the genital band from which it sprang. Tlie mass appeai-ed to be glandular throughout and was distinctly tinged with a reddish-yellow, like the nephridiiun. In a niunber, the surface was covered with globular, transparent cells tipped with minute yellow granules appar- ently identical with the knobs already desci'ibed as tipping the filiform spermaries which, we saw, arose from the vesicle, or from its immediate vicinity and also identical with the reddish-yellow cells marking the sperm.aries in the pallial lacunae. In some, a secondary vesicle was found (59: Sre), and in otliers incipient vesicles were budding in close prox- imity (59: 1). A number of my drawings show externally a granidar surface and a structure within, that in one case seemed to be a round, distinct cavity with light reddish-yellow walls. In another instance, I observed what appeared to be an elongated cavity which made nearly a complete turn within the vesicle, one extremity being larger than the other (59: 2). In another case a varicose mass ran over the surface of the 3"0 EDWARD S. MORSE ON vesicle (59: 4, 7). Under various pressures, no fluid, or other contents could be forced out at its point of attachment with the genital baud, nor was any opening or duct found upon its surface. There was a slight glandular thickening on the edge of the genital band (59: 8), and a similar thickening was fouud on the posterior edge of the ilio-parietal band, as shown in 56: 2. In T. coreanica, the edge of the ilio-parietal band is not only thickened, but it has the reddish-yellow coloration that we have seen associated with the spermaries, and which also tinges the vesicle in those forms studied. This colored glandular thickening of the edge apparently runs from the central vesicle to the accessory vesicle without a break. In 39: 12, this feature is shown in color. The central vesicle resting on the posterior dorsal surface of the stomach was bluntly triangular in shape, with the base anterior, and the sides of the triangle strongly lobulated. From the median line in front, the band, which Hancock mistook for an artery, divides and passes forward and downward on the sides of the stomach and then, laterally, making three short flexures, turns abruptly backward to terminate in the accessory vesicles. It may be observed that these flexures are the result of the loose folding of the ilio-parietal band and this so-called artery arises from the edge of it. It will be oljserved that this structure, from the central to the lateral vesicles, is distinctly tinged a reddish-yellow and, as before observed, it is the color which tips the filiform spermaries and other parts of the genital apparatus already described, but I have not observed this color associated Avith the eggs in Terebratulina, though the purple ovarian leaflets in T. coreanica were tipped with it. It is a very significant fact that no blood vessel, sinus, or lacune shows a trace of this color. In another specimen of T. coreanica, the central vesicle was oblong and was thrown into a series of folds or plications (59: 10, ll). The folds were slightly darker in color. With transmitted light, no cavity was detected within, and it seemed to be made up of irregular masses of radiating tissue which appeared glandular. No channel could be detected at its point of attachment, nor was a trace of muscle fibers discerned. The lateral or accessory vesicles (59: 12, 13), seem to have the same structure without folds or plications. The exterior surface of the accessory vesicles was granulated with minute cells, with a yellowish substance interspersed. Precisely what role these various parts play in the organization of the animal, I have not made out, but that they are intimately related to the genitalia, there can be no doubt. It may be added here that while the nephridia, as well as many other parts of the anatomy, in all species examined, reveal the presence of ramifying lacunae through which the blood is seen rapidly circulating, these vesicles, central and accessory, are about the only organs which show no trace of any circulating fluid within or without. LIVING BKACHIOPODA. ^'l External Glands. A curious paired organ of which I published a short account some years ago ('72) has, with this exception, never been observed before. These organs are found chistered around the exterior nipple-like openings of the nephridia in T. septentnonah.. Plate 60 is devoted to illustrations of these bodies. They form conspicuous, white, lobulated masses arisino- from the space between the external orifices of the nephridia. The lobules, to the number of ten or twelve, vary in shape from one another, and are by no means alike on each side • in this respect forming a marked exception to the strictly bilateral and symmet- rical repetition of parts in the Brachiopoda. In one instance a peculiar lobulated structure ensheathed the nephridial tube, apparently within the coelomic wall (60 : 8) . Tt seemed to be of the same nature as the external glands. A distinct wall surrounds each lobule, thou-h this wall varies in thickness, being somewhat thicker at the extremities. The lobules stand quite free from each other and have a narrow base of attachment. They all seemed to be clothed with a ciliated epithelium. Under pressure, irregular granules were forced out and these vibrated in such a manner that I first mistook them for spermatic particles At 60: 12, is represented the appearance of these lol>ulated masses as seen from below They stand quite free and prominent frcm the coelomic wall. Between these masses is seen a distinct prominence ; viewe.l fn.m in front, this prominence is bordered by an encirchng line (60: 6). In 60: 1, its position in relation to the mouth and other parts is shown ; in this figure, also, a clear idea may be had of the position of the external glands in relation to other parts of the structure. In 60: 13, a rough outline is given representing a longitudinal section of T. septentrionalis for the purpose of indicating the exact position of the external glands in relation to other parts of the anatomy. The spiculae which abound in the pallium, brachia, and cirri of this ammal, are also found in the external layer of these glands (60: 5, 7, lU) . Precisely what may be the function of these external glands I do not know. Mucous secretions occur abundantly about the external openings of the nephridia and the mouth, and it may be that these are simply mucous glands. Whether they may be com- pared to the dermal glands of the chaetopod worms is a question, though it is stated that the dermal -lands in worms form an investment for the ova; but the ova of Terebratulma are not in^°ested with mucus. With the idea that they are glandular, I have given to them the name of external glands. I have not observed them in other Testicardine forms, though they will doubtless be found. From their intimate association with the external ducts of the nephridia, it seems reasonable to believe that in some way they are connected functionally with the genitaha. 372 EDWARD S. MORSE ON The nearest approach to these organs has been described by Schulgin in Cistella. He says, "Argiope [= Cistella] has not far from the mouth, on the integument an accumula- tion of cells which play the part of an organ of sense. This organ consists of two longish heaps of cells lying parallel to one another, of which that lying nearer the mouth is formed of specific cells and that farther away from it of epithelial cells." Schulgin figures these organs as projecting from the coelomic wall and describes them as one Tljove another in a median line. He makes no remark about their relation to the external openings of the nephridia, yet there would seem to be some relation between these bodies he describes and the external srlands. Early Stages. In the previous pages, reference has often been made to the early stages of the shell and the soft parts of these animals; there are other features to be briefly alluded to, however, and in plate 61 I have brought together a number of outlines of the early and nepionic stages of various forms for purposes of comparison. The illumination which Beecher ('92) has shed upon the phylogeny of the Brachiopoda from what little we yet know of the ontogeny, has been based upon material of this kind. In this study he has found a confirmation of certain principles of evolution first enunciated by the lamented Hyatt. In the plate above referred to, I have taken the liberty of reproducing for con- venience of comparison four outlines of the early stages of Terebratulina from my Embry- ology of that species. In 61 : 1 is represented the posterior portion of the shell of an undescribed Lingula from Nagasaki. I made only the briefest observation of the animal, and have no idea of the meaning of the structure outlined within. The nepionic outline with the straight posterior margin is similar to that seen in L. lepidula (42 : 3, 4) , except that it is somewhat broader. In D. lamellosa, at an early stage, the bases of the oblique muscles are slightly flaring, a feature not seen in maturity. In a very early stage (61 : ll) , tliese muscles are excessively flaring at their point of attachment. In a stage where the brachia are well formed, numbering thirty or more cirri, the various muscles may be clearly defined, except that the separation of the anterior occlusor into two muscles ii not apparent though the lateralis is well developed. The anterior and posterior occlusors are compacted within a short space. In 60 : 10, a supernumerary muscle, apparently a repetition of the obliquus posterior, is shown on the right side. Blochmann has figured, in an adult specimen, the same anomaly on the left side. The disproportionate size of the anterior and posterior setae in the young is well shown in the drawings. The nepionic shell (61: ll) is absolutely circular; in this figure the few cirri, seven or eight in ninnber, are turned towards the mouth. The coelomic wall shows distinctly two sets of muscles crossing each LIVING BRACHIOPODA. 3/3 Other obliquely (61: 8, (l)all). Studies from the biological laboratory, Johns Hopkins university, vol. 3, p. ■2:J7-2(i.'>, jil. 14-17. Blochraann, Friedrich. :01. Untersuchungen iiber den ban der brachiopoden. Jena : verlag. v. Fischer. Bloomfield, J. E. . '80. On the development of the spermatozoa. Part 1. Lumbricus. Uuart. journ. micros, sci., new series, vol. -0, p. 7'J-89, pi. 0, 1 fig. Brooks, W. K. , , • , , v, . '79. The development of Lingula and the systematic position of the Br^ichiopoda. Chesapeake zoological laboratory, Johns Hopkins university, p. 35-112, pi. 1-6. Carpenter, W. B. '56. On the minute structure of certain brachiopod shells ; ami on vegetable cell-formation. Annals and mag. of nat. hist., 2d seri&s, vol. 17, p. 602-50(1 Claparede, E. on i - '69. Les annelides chfetopodes du golfe de Naples. Part 2. Mem. soc. de phys. et d'hist. nat. de Genfeve, t. 20, lere part., p. 1-225, pi. 17-31. Crane, Agnes. '92. Recent observations on the anatomy and development of the Brachiopoda. Natural science, (London), vol. 1, no. 8, p. 603-611, 1 fig. '93. New cla,ssifications of the Brachiopoda. The geol. mag., (London), new series, vol. 10, p. 318-323. Dall, W. H. '71. Report on the Brachiopoda, etc., with a revision of the Cranihlae and Discinidae. Bull. nms. comp. zool., vol. 3, no. 1, p. 1-45, pi. 1-2. Davidson, Thomas. w « i 9i '86-'88. A monograph of recent Brachiopoda. Trans. Linn. soc. London, 2d series, vol. 4, p. 1-248, i.l. l-oO, hg. 1-Z4. Ekman, T. i • d « '96. Beitrage zur kenntnis des stieles der brachiopoden. Zeit.schr. f. wissensch. zoOl., vol. 62, p. 16'J--4i), pi. O-.t, tig. 1-0. Francois, Ph. '91. Choses de noumea. 2. Observations biologiques sur les lingules. Archiv. de zool. experiment., 2ieme .s6ne, t. J, p. 231-239, 2 Ugs. Gegenbaur, Carl. '78. Elements of comparative anatomy. English ed., 8", ill. Gill, T. '73. On the primary divisions of the braohiopods. Annals and mag. of nat. hist., 4th series, vol. 12, p. 201-20... Hancock, A. '59. On the organization of the Brachiopoda. Philosoph. trans, royal soc. London, vol. 148, p. 791-869, U pis. Huxley, T. H. '56. Contributions to the anatomy of the Brachiopoda. Proc. royal soo. London, vol. 7, p. 106-117, fig. 1-2. Joubin, L. ■ , iki Qm '86. Kecherches sur I'anatomie des brachiopodes inarticulfe. Archiv. de zool. experiment., 2ieme sene, t. 4, p. 161-.W3, pi. 7-15, lig. 1-3. '92. Kecherches sur ranatomie de Waldheimia venosa (Sol.). Mem. .soc. zool. de France, t. 5, p. 554-583, hg. 1-26. King, W '70. On the histology of the test of the class Palliobranchiata. Trans, royal Irish acad.. vol. 24 (science), p. 439-455, pi. 20. Kowalevski, A. A. '74. Observations on the development o£ Brachiopoda. (In Ras.sian.) Proc. imper. soo. amat. naturalists, Moscow. •^^*^ EDWARD S. MOUSE ON Lang, Arnold. '96. Textbook of roiuiiarativc anatomy. I'art 2. London. Tian.sl. by H. M. and M. Heniard. Lankestcr, K. K. '73. Sunnna.y of ^odlo-ical ob.servalions „,a,l.. al .\a).le.s in Ihu winter of 1871--72. Annal.s and ma-, of i.at hisf -111, serie.s, vol. 11, p. 81-!)", fig. 1-3. Macdonald, J. D. '61. On the physiology of the pallial sum.es of the Hraehiopoda. Trans. Linn. soc. London, vol. 23, part ■> p. 373-375 pi. 35. ' ' Morse, E. S. •70. The lirachi,.poda, a division of Annelida. Anu-r. journ. sei. and art.s, 2d .serie,^ vol. .50, p. 1(10-104, ««. 1-3. '71. (hi the early sta,i;e.s of TerrhnituUna .'. — dorsal shell. di. — divaricator muscle. e. — eggs. e. e. — ectodermal epithelium. e. g. — external glands. en. — endothelial lining of pallium. e. o. — external oblique muscle. e. s. — encircling sinus. f . — faeces. f . f. — folds of funnel. f . y. — fibrous yoke. g. — gut. g. a. — gill ampullae. g. b. — genital baud. g. b. s. — great brachial sinus. g. en. — glandular enlargements. g. {.—gill fold. g. g. — glandular growth on edge of ilioparietal band. gl. — gland cells. gp, — ^gastro-parietal band. g. p. a. — ganglion of posterior adductor muscles. gp. ni. — gastro-parietal mu.scle. g. t. — glandular tip of spermary thread. H. — " heart of Hancock." i. — intestine. i, I). — inner band of pallial muscles. in. — infra-oesophageal ganglion. ip. — ilio-parietal band. i. t. — inner tube. 1. — lateralis muscle. la. — lacunae. ]. b. — lateral branch of anterior sinus. 1. i. — lumen of intestine. 1. p.— lateral parietal band. 1. p. s. — lateral pallial sinus. 1. s. — lateral septa. m. — mouth. m. cl. — median clu.ster of setae. m. f. — muscle Kber. m. g. — median groove of pallium. m. p. — main pallial sinus. m. s. — median septum. m. si. — median sinus. m. t. — nuLscular tube. n. — nerve. n. b. — nephridium body. n. ba. — nephridial band. ne. — nephridiiun. nf. — nephrostonie. n. o. — nephridial opening (external). n. p. — nephridial papillae. n. s. — natural size. n. t. — nephridial tube. o. a. — obliquus anterior muscle. o. b. — outer band of pallial muscles. oc. — anterior occlusor mu.scle. oc. I. — occlusor externus muscle. oc. II. — occlusor internus muscle. oe. — oesophagus. o. e. — obliquus externus muscle. o. h. s. — outer horny sheath. o. i. — obliquus internus mu.scle. 0. 1. s. — opening of lateral sinus. o. m. — obliquus medius muscle. o. p. — obliquus posterior muscle. o. p. s. — outer pallial sinus. o. s. — opening of main pallial sinus. ot. — otocyst. ov. — ovaries. pa. — parasite. p. b. — posterior band. p. b. I. — posterior branch of lateral siims. p. c. — peduncular cavity. p. ca. — peduncular canal. p. ch. — pallial chamber. p. cl. — posterior cluster of setae. pe. — peduncle. pb. — phai-ynx. ph. g. — pharyngeal gland. ph. m. — pharyngeal nni.scles. p. lu. — perivisceral membrane. p. n. — peduncle notch. p. o. — posterior occlusor muscle. pro. — protegulum. p. s. — peduncular septum. p. si.^ — peduncular sinus. r. — rectum. r. b. — retractor brachia nm.scle. re. — rectus muscle. ro. — rostrum. s. — sinus at base of cirri. s. b. — shell border. s. b. s. — small brachial sinus. .se. — setae. s. f. — setigerous follicles. s. g. — stomachal glands. s. g. d. — stomachal gland duct. s, g. o. — stomachal gland opening. s. ni. — setal muscles. sp. — spermatospore. spe. — spermaries. .spi. — spiculae. spm. — .spermatozoa. sp. t. — spermatic threads. s. s. — supporting substance. .ED\VAi;i) S. .Mol.'.sK ()\ s. t. — setal tubes. sU). — stomach. su. — supernumerary muscle. t. — testes. V. — ventral .slicll. V. m. — ventral mesentery. V. r. — ciliary ridge of visceral .sinus V. t. — va-scular twig. PLATE :i'.i. Kejiriiductidn.s iif ori<;inal (lr:i\vinf;s tn illiisliatc colipr in livin;; Hracliin].iicla.' Fig. 1. hingula lepidulu horn ventral side. Fig. 2. Brachia of L. kpidula showing color of border and rirri. Fig. 3. Anterior portion of ijalliuni of L. lepidnla. Fi.g. 4. Portion of pallium of Gloltidiri pi/raiiiidnln showing three rows of gill ampullae and pigmentation between. Fig. "). View of pallium .showing anterior pallial folds. Fig. ti. Enlarged view .showing ])ign]entation of pallial fold. Fig. 7. Cirrus of G. j;;/m,)/(((/(i^t shciwing pigmentation. Fig. 8. Nephridia of Didlhui ynti/n. Fig. 9. Nephridia of Tenibnitulinn mptaidrioiudin. Fig. 10. Spermary thiead of T. sfptentrtnuidis. Fig. 11. Itorder of palliinn of TtrihrtiUdin cureanirn. Fig. 12. Slomach and immediate parUs of T. cureaiiira. Fig. 13. Ovarian leaflets oi T. coreaiiica. Fig. 14. Pallium and pallial .sinuses of T. rureiuica filled with eggs. PLATE 40. Appearance in life of \arious forms. Fig. 1 to 5. l!loUidi. Setae of DhclniKru slclla. Fig. 3. Various forms of .setae. Figs. 4 and •'J. Appearance of setae .springing from iiiiUium. Fig. 6 to 10. Setae of Disrinitica liiineUosa. Fig. 6. Setae of extreme young. Fig. 7. Setae of adult. Fig. 8. Portion of iialliuni showing setae springing from setigeroiis follicles with setellae turned back. Figs. 9 and 10. Setae of yotuig. Fig. 11. Seta from extreme young of T. septentrlonalis, with setigerous follicle. Fig. 12. Border of pallium of Terebratalia coreanica showing setae. Fig. 13. Border of pallium of Terebratalia minor showing setae. Fig. 14. Seta of Lai/ueus ruhiilus. Fig. 15. Border of pallium of Heiailliyri^ psittarca showing setae. PLATE 45. Various life attitudes of the brachia of Ohittidia pyramidata and Liu(iiila lepidida. Fig. 1 to 12. Olottidia pyraiiiidata. Fig. 1. Dorsal view. Fig. 2. Ventral view. Fig. 3. Dorsal view. Figs. 4, 5, 6, and 10. Anterior views. Fig. 7. Oblique anterior view with shells slightly parted. Fig. 8. View of brachia from ventral side. Fig. 9. Left brachium, ventral surface uppermost. Figs. 11 and 12. Lateral view. Fig. 13 to 15. Linf/ula lepidula. Fig. 13. Dorsal view. F'ig. 14. Anterior view. Fig. 15. Ventral view. PLATE 4fi. Br.achia and cirri of various forms. Figs. 1 and 2. End of cirrus of G. pyramidata. Fig. 3. Portion of brachia with collar and one cirrus of L. lepidula. LIVING BRACIIIOPODA. 381 Fig. 4. Brachia of L. lepidula, with cirri removed. Fig. 5. Terminal lialf of cirrus of L. lepidula, sliowing pigmentation. Figs. 0 and (! and 'Ic. Appearance of surface of nephridium. Fig. 3. Nephridium, with genital band, accessory vesicle, etc. Fig. 4. Pedimcular end of young specimen showing nephridia. Fig. 5. Very young sijecimen showing nephridia. Fig. 5a. Nephridium greatly enlarged. Fig. 6. External opening of nephridium, front view. Fig. 7. Side view of nephridial opening showing nipple-like fornr Fig. 8. Nephridia of Dallimi grayii. Fig. 9. Nephridium of last, showing more clearly the crenulateil character of nephrostome. PLATE f)7. Genital products, etc., of various forms. Fig. 1. Ovaries and .stomachal glands of Glottidia. I'ig. 1(1. Portion of stomachal glands. Fig. 16. Portion of ovaries. Fig. 2. Mass of spermaries of Glottidia. Fig. 3. Mass of spermaries of L, iimdina. Fig. 4. Mass of eggs of L. lepidula. Fig. 5. Mass of eggs of Glottidia. Fig. 5o and 56. Eggs in various stages. Fig. 6. Eggs of Discinisca stella. LIVING BRACHIOPODA. 385 Fig. 7. Slomacli, stomachal glands, ami right occhisor muscle of D. Idiiiiilosd with ilio-parietal liaiid turned forward to show ovaries arising from it. ^ Fig. 8. Greatly enlarged view of ilio-parietal band from above; Kgure showing proliferation of genital strands with eggs in masses. Fig. 9. A group of eggs attached to genital strand, idem. F^ig. 10. A group of eggs attached to genital strand, greatly eidarged, idem. Fig. 11. ])or.sal and ventral half of pallium of T. carcanira, with main pallial sinu.ses and lacunae tilled with eggs ; .see 39: 14, for color. Fig. 11a. Terminal lacunae, showing ciliary ridge. Fig. 12. Masses of eggs, idem. Fig. 13. A single mass of eggs, greatly enlarged, idem. ¥\^. 14. Side view of portion of mass, idem. Fig. 1.5. A highly magnified view of a few leaflets tilled with eggs, idem; see 39: 1.3, for color. The yellowish liorder so characteristic of all membranes associated with genital activity may be seen in the last reference. PLATE 58. Genitalia of Tereiiratiilind septintrionalis. Fig. 1. Animal in the act of ovipositing. Figs. 2 and 3. Small lacunae and spiculae with corpora lutea. Fig. 4. Showing eggs escaping from the lacunae of the pallium, passing through the nephridium, and issuing from the external opening. Fig. 5. Cluster of eggs from genital band. Fig. 6. Eggs in'laoune. Fig. 7. Left nephridium witli cluster of thi'ead-like sperjnaries below. Fig. 7a. Sperm threads under a compressor. Fig. 8. Greatly enlarged view of a few sperm threads. Figs. 9 and 10. Individual sperm threads showing glandular tip aiul spindle-shaped termination with spermatozoa; see 39: 10, for color. Fig. 11. Lacunae filled with sperm masses. Fig. 11a. Portion of same. Fig. 116. Spermatozoa. PLATE .59. Vesicular organ known as "accessory heart of Hancock," of Terehratulina septentriunalis, and central and accessory vesicles of Terebratalia coreanica. The accessory vesicle will be designated as genital gland. Fig. 1 to 8. Terebrntulina septentrional is. Fig. 1. Genital gland springing from genital band with suiiplementary vesicles near. Fig. la. Enlarged view of surface showing spermatoblasts. Fig. 2. Genital gland more developed with glandular growth at base. Fig. 3. Genital gland with supplementary gland at side. Fig. 3a. Much enlarged view of same. Fig. 4. Genital gland arising from slender stalk with glandular outgrowtlLs on surface. Figs. 5, 6, and 7. Genital glands in various stages of development. Fig. 8. Portion of genital band thickened and strongly ciliated. Fig. 0 to 13. Terebratalia curuaiiica. Fig. 9. Stomach with so-called heart and genital glands at end of mam pallial sinus, with glandular cord connecting them with the .so-called heart ; .see 39 : 12, for color. 386 EDWARD S. :\rOKSE ox LIVIN(; r.liACIIIOPODA. Fig. 10. So-called heart. Fig. 11. Another view of same organ slii;htly coiiipresseil. Fi"s. 12 and 13. Different views of genital gland. I'LATK i;o. External gland.s of Trn-bi-dtuUna septentrloindis. Fig. 1. Shells thrown wiih/ly apart rnptnring anterior coelninic wall, .showuig braehia, position of nephriclia and relation of external glands to nephiidial openini^s. Fig. 2. Another view of nephridia with external glands. Fig. 3. External gland compressed with glandular particles forced out. Fig. 4. Greatly enlarged view of lobule of external gland showing ciliated ei>ithelinin. Fig. 5. External gland showing spiculae on .surface. Fig. G. Nephridia with external glands surrounditig their terminations. Fig. 7. Greatly eidarged view of right nephridial tube with external glaiul. Fig. 8. Tubular portion of nephridia ensheathed by external gland. Fig. i). Another view of nephridium .surroundeil liy lobules of external gland. Figs. 10 and 11. External glands. Fig. 12. Ventral view of anterior wall of coelomic cavity showing promiueiu character of external glands with azygos process between. Fig. 13. L(nigitudinal section of T. septentriomilin, showing position of external glands projecting iiuo pallial cavity. PLATE fil. Early stages of various forms. Fig. 1. Lingula, species unknown, from N:igasaki. Figs. 2, 3, and 4. Discinisca steltii. Fig. 5 to 12. I), lamellosa. Fig. 13 to It). Various stages of T. aeptentrioniUis, reproduced from the author's memoir on early stages of this species. Fig. 17. Ilemithyris psittacen. The natural size is indicated by the small outline. Printed, July, 1!)02. ^'^^'^" MEMOIRS OF THE BOSTON SOCIETY OF NATURAL HISTORY J * VOLUME 5, NUMBER 9. ^HE SKELETAL SYSTEM OF NECTURUS MACULATUS Rafinesque. By HARRIS HAWTHORNE WILDER. Ph. D. BOSTON : published by the society. January, 1903. .UN "~ "?^3 y. The Skeletal System of Nectukus maculatus Rafiuesque. By Harius Hawtiiokne Wilder, Ph. D. (Read February 19, 1902.) Introduction. In view of Gaupp's recent reAdsion of Die Anatomie des Frosches, Professor von Bardeleben says, '' Es ware im Interesse einer besseren Fundamentirnng der verglei- elienden Anatoniie luiehst wunschenswert, wenn bald zu den wenigen ausfiilirlichen Monographien von Wirbeltieren einige neue, z. B., je eines Selachiers, Gauoiden, Tele- ostiers .... eines Urodelen .... einiger Reptile und uiederen Sanger, besonders Insecti- voren, kjinien. . . . Wer wagt es ? " Tbe following paper is an attempt to cany out the suggestion of the above quotation as far as it concerns a Urodele ; and it is hoped that, as occasion allows, papers upon the other systems of Necturus may be added to this and thus gradually complete a monograph upon the anatomy of a typical tailed amphibian. In the selection of Necturus to serve as a type, I have been guided by several reasons, mostly of a practical nature. JVectums maciiJatus is probably the most abundant and widely distributed Perennibranch in the world, and owing to this fact, as well as to its large size, is employed as universally in American laboratories, as is the Salamandra maculosa in Europe. This exploitation of the .species as a laboratory animal has led to the development of means for its capture in quantity for such purposes, and it is thus by no means so uncommon an ol)ject of study in the laI)oratories of Europe as it was a few years ago.' Anatomically and structurally considered, the choice of an animal to represent the Urodela should be either that of a highly specialized one, thus emphasizing those charac- ters which are essentially Urodelau ; or tliat of one taken from the most primitive group, which would have the two advantages of showing each organ in its simplest condition, and of suggesting the phylogenetic origin and relationship of the entire order. Granting that the second of the above alternatives has the most in its favor, the choice would be limited to one of the Proteidae, a family represented by three generic 'Necturus is supplied at present at must of the American universities at $10.00 per hundred, and altliough just at present there is an attempt being made liy dealers to advance the price, especially of those exported to Europe, such con- ditions cannot last long. 388 HARRIS IIAWTIIORXE WILDER ON groups, which are partially or Avhollj subterranean in their habits and thus modified in various degrees to conform to this environment. Proteus is an inhabitant of certain caves in Austria, and shows, among other troglodytic characters, reduction of ejes, loss of pigment, and a pronounced attenuation of bod}^ and limb, the latter combined with a loss of toes. These aberrant characteristics are still more marked in the recently discovered Typhlomolge, which occurs in a subterranean river in the state of Texas. The third and last member of the group, Necturus, occurs in the Great Lakes and other open waters, and, corresponding to its freer life, shows the least modification. It remains by day beneath stones or in subterranean burrows constructed by itself in the mud, and becomes active at night, swimming through the water in search of prey. Its body and legs are robust, and do not show the slender proportions seen in Proteus and Typhlomolge. Its eyes, though small, are functional, and it is well pigmented, especially above. It is thus at the same time a representative of the lowest group of Urodeles, and one not extremely modified. The genus Necturus is exclusively North American and includes but one common species, iV. maculatus Raf., although the series of synonyms, as well as some variability of marking, have combined to give the general impression that there is a large number. Aside from N. maculatus Raf., Cope enumerates a second species, N. punc-tatus GibbeS; of rare occurrence and found only in the waters of North and South Carolina. Necturus maculatus, the subject of this memoir, is a widely chstributed form and occurs in abundance in the Great Lakes and their tributaries, and throughout the entire Mississippi valley, as well as in many of the river systems of the Atlantic slope, and those flowing into the Gulf of Mexico. Its abundance and extensive distribution have led the United States government to conduct experiments relative to its introduction as a " food fish," thus far with satisfactory results. In form and appearance it is similar to that of a larval salamandi'id, and is subcylindrical, body slightly and head markedly depressed, with three large and bushy external gills upon each side, ha\iug two gill slits between them, and with four decidedly robust legs, each witli four toes. The tail, which does not exceed half the length of the body, is compressed and surrounded dorsally, caudally, and ventrally by a caudal fin, rounded in outline at the tip. Sexually mature adults seem to be fairly constant in size, vai'ying in total length between about 27 cm. and 34 cm. The color markings of the integument are due to scattered pigment cells, the varia- tions in the frequency and size of wliich result in the formation of all possible shades between no color at all and dense black spots. As these cells are very large, and in most places evident to the unaided eye, the principle is seen upon close inspection to be similar to that of a modern half tone illustration, which a careful scrutiny resolves into a series of black dots, although in the latter case the darker shades are due to increased size, and in NECTURUS MACULATUS. 389 the former to an increased number of the elements involved. The ground color of the skin, as may be seen on the ventral side, which is mainly free from pigment, is yellowish or pinkish, but over the sides and back varying degrees of pigmentation produce diiferent shades of slate color, in places with a distinct bluish or purplish tint. The deepest pig- mentatiou is that of the dorsal side wliere certain densely pigmented areas form irregu- larly rounded black spots upon a bluish-slate background, thus suggesting the specific name of " mdculatus.^'' ^ The skeleton consists of several independently separable portions and, like that of other Urodeles, contains a large amount of uuossified hyaline cartilage. By far the largest portion consists of the vertebral column, the skull, to which is attached the hyo- branchial complex, and the posterior extremities, which are attached by the ilia to a single sacral vertebra. The two halves of the shoulder girdle are free from one another and from the rest of the skeleton, and they, with their corresponding free limbs, form two dis- tinct skeletal parts. The remaining skeletal elements are the nasal and optic capsules, the two laryngo-tracheal cartilages, and the series of rudimentai-y sternebra which lie in the mid-ventral thoracic region. All of these latter parts are wholly cartilaginous and entirely disconnected from other parts of the skeleton. In arranging the descriptive material of this memoir, the above practical division of the skeleton has been taken into consideration as well as the more usual morphological one, and it has seemed best to arrange the subject in the order following. In this the vertebral column will be first treated, together with the ribs and sternum. The visceral arches and the free sense capsules will be treated with the skull, and the limbs and their girdles will appear last. This brings the parts together in their topographical relation- ships and will be found more practical than a wholly morphological di^^sion. The Vertebral Column. General Description. The vertebral column, as is the case with fishes, shows little regional differentiation, since the limbs are too small and weak either to modify the motions of the trunk by the muscles attached to them, or to bring their places of attachment into prominence as points of leverage or support. The only gain in this respect over the condition seen in 'Ju-st as this manuscript leaves my hands, I have received from Mr. Alexander Nielsen, of Venice, Erie county, Ohio, an extensive dealer in Necturus, a .specimen having a totally different coloring from the asual one, and Mr. Nielsen, who has caught thousands of specimens, writes that it is the firet of the kind he has ever seen. The ground color of this speci- men is a light reddish buff, with no sugge.stion of the usual dark slate color. The back is covered with dark brown spots, smaller than in the normal forms. In form and size it closely resembles the common species. 390 HARRIS HAWTHORNE WILDER ON fishes is the direct attachment of the pelvic girdle, which by the medium of a specialized pair of ribs, becomes articulated to a single vertebra, usually the 19th. This vertebra, the sacral, lies naturally in the cloacal region and it seems a matter of douljt whether, as in higher forms, to consider it the boundary between the trunk and the tail, or whether as in fishes, to limit the latter region to those vertebrae which bear closed haemal arches, the first of which is usually the fourth vertebra posterior to the sacral one, /. e., the 23d. The first of these alternatives seems the more natural and open to the fewest objections, for, while it places the first few caudal vertebrae in the same list structurally with those of tlie trunk, from which, indeed, they are practically indistinguishable, it avoids the equally great embarrassment of lea\dug the same number as a nameless and anomalous group intervening between the sacral and caiidal regions, a relationship unlike anything occurring elsewhere among vertebrates. The statements given above, that the two vertebrae which have a definite distinction, the sacrum and the "first haemal arch vertebra," are usually the 19th and 23d respec- tively, suggest variation in tliis order, a matter which has been made the subject of papers by G. H. Parker ('96) and Bumpus ('97), and has been referred to by Waite (97). Regarding the sacral vertel^ra, according to the first two authors it was the 19th in 65% of 127 specimens examined, the 20tli in 27% and in the remaining 8% it was placed " obliquelj-,'' that is, A\ith au attachment to the 19th vertebra upon one side and the 20th upon the other. This obliquity is usually sinistro-dextral, i. e., with the left sacral rib in advance of the right (left, 19tli; right, 20th). Out of eight such oblique specimens examined b^' Bumpus, seveu were sinistro-dextral, and only one dextro-sinistral. Parker's two specimens were both sinistro-dextral. Waite describes three oblique specimens, which show for the most part additional abnormalities. In one of these the right sacral rib was on the 19tli vertebra and the left on the 20th, thus making the direction dextro-sinistral. In the other two cases the right rilj was on the 18th, a case not found by the other authors named, and the left on the 19th, again dextro-sinistral. Waite also figures a case with two normal sacral ribs on the 19th vertebra, and an additional smaller rib upon the right side of the 20th, also attached to the ilium. A similar variation occurs in the position of the 1st haemal arch, although a careful comparison by Bumpus has shown that variation here is entirely independent of that of the sacral vertebra. Out of 98 specimens examined with reference to this, the 1st haemal arch was borne on the 22d vertebra in 11 specimens, on the 23d in 82, and on the 21:th in 5. The variation in the total number of vertebrae, which is considerable, is seen to be mainly that of the caudal region, as it has been shown that there is a variation of but two NECTUIIUS MAOULATUS. 391 vertebrae at the sacrum, aud but three at the first haemal arch. The results of countiua' the vertebrae iu 100 specimens are expressed bv Bumpus in the following table: — No. of vertebrae. No. of specimens. 43 9 ■XtJ 44 0 45 21 46 18 47 14 48 16 49 11 50 5 51 4 100 By tliis it will be seen that the average total number is 45 or 46. A Typical Vertebra. In order to understand the structure of the separate vertebrae, any trunk vertebra except one of the first two or three may be selected as a type and its parts studied in detail, after whicli the differences seen in other regions may be noted, and a few special vertebrae selected as worthy of individual study. The 16th vertebra has been selected for this purpose, and four views are given of it in text figures 1-4. These figures were drawn from a dried vertebra prepared l)y macer- ation in caustic potash and hence lack the cartilag- inous portions and other related soft parts referred to in the text. This vertebra consists primarily of a ventrally situated centrum or body; a neural arch, the dorsal aspect of which is broadened out into a Ijroad, flat plate ; and upon each side a complicated transverse process directed backwards and bearing a short rib which articulates with it in two places. The centrum is in the form of a slender hour glass, its ends marked by very deep cup-shaped depressions, thus making the entire vertebra con- Fig. 1. lijtli vertebra ; dorsal aspect. X 3. 392 HARRIS HAWTIIORXE WILDER ON vt™('»U Iviff, ones under consid- eration, completes the enclosure of the foramen magnum. Tliis basi-occipital cartilage is of greater extent in young and larval annnals, and the ventral alae result from the gradually increasing ossification of its lateral ends. As this process continues towards the center, the inner angles of the bone nearly touch one another in old adults, while the cartilaginous arch is correspondingly dimmished. The exoccipital comes into contact with four bones: (1) the parabasale, which is closely applied to the basi-occipital ala, (2) the opisthotic, which, in adults, touches both the body and the dorsal margin of the supra-occipital ala, (3) the parietal, a bit of the posterior margin of which becomes applied to a corresponding portion of the dorsal mar- gin of the supra-occipital ala, within its contact with the opisthotic, and (4) the atlas, which articulates with the condyles by a movable joint. The natural relations of an isolated exoccipital are best learned from the flat ventral surface The condyle is po.sterior and the long straight edge is internal. 4 QUADRATUM. This is primarily a cartilaginous element, associated with the primordial skull, and representing the proximal (posterior) end of the palato-pterygo- quacbate arch, the functional upper jaw of the Selachians. In the Anura this arch is entire, but in Necturus it is represented by its two ends alone : the antorbital process, which' represents its anterior, and the quadratum, its posterior portion. Functionally it serves as a " suspensorium," or piece interposed between the skull and the mandibk, and forming an articular surface for the latter. This joint occurs at its outer anterior angle, and that region of the quadrate becomes ossified, plainly to give strength to this very important joint. It thus happens that there is in the adult, both an osseous and a cartilaginous quadrate, the former being situated externally and the latter towards the median line. The irregular shape of the quadrate taken as a whole may best be seen by a reference to figures lO^nd 11 (plate 04). The external osseous portion consists of an antenor articular process of very hard bone, fitted with an articular socket to receive the rounded cartilaginous knob (articulare) of the mandible, and a hollow trough-like posterior process fitted over the outer edge of the cartilage much as in the case of many of the dermal bones. The cartilaginous portion consists of a flattened plate which attaches by its broad- est side to the bony portion and tapers down to a narrow isthmus as it approaches the skull Contact with the latter is formed by means of anterior and posterior extensions ot the isthmus, which become applied to the outer side of the trabecula just in trout ot the 410 HARRIS HAWTHORNE WILDER ON otic capsule. It is (lifficult to (leterniiiie. in a piece of this shape, the location of the proc- esses cited by aiitiior.s in their description of the ([iiadrate of other Aniphil)ia. The p(js- terior lateral extension which runs along the side of the bone is probably the otic process, and tlie narrowed part, or its posterior prolongation, tlie pedicel. Of the two processes which form the isthmu.s and become applied to the trabecula, the anterior one may possi- bly be the ascenchug process. A slight angle seen in the anterior margin is doubtless the rudiment of the " cartilaginous pterygoid " found in most Urodeles, the extension of which to the antorbital process would form the palato-pterygoid arch wdiich is wanting here. Aside from its attachment to the trabecula, the quadrate, osseous and cartilaginous, enters into more or less complete attachment to four bones. As described al)ove, two processes of the pi'o-otic form quite definite articulations with the (piadrate cartilage, the \entral one receiving an articular surface formed by a thickened piece of cartilage in the middle of the posterior margin, and the dorsal one being applied along the inner edge of the otic process. The para(iuadrate overlaps it externally, and tlie outer posterior corner of the palato-pterygoid fits into a gi'oove in the inner side of the articular process and overlaps a raised area of the quadrate cartilage. The cartilaginous articulare of the mandilde forms a movable articulation with it. In determining the position of an isolated osseous quadrate it may be remembered tliat the side showing the liollow groove is internal, that the larger end is anterior, and that the broader, plainer surface is dorsal. 5 and 6. paraquadratum and opercu- lum. These elements, oi wdiich the first is a dermal bone, and the second an ossification of a detached portion of the otic capsule, are closely connected topographically and joined to one another by a strong ligament whicli unites processes in each bone mutually directed toward the other. The paraquadra- tum, the shape of which suggested a boom- erang to Huxley, attached in its normal man- ner to the little discoidal operculum, presents the appearance given in figure 1 1. When in place upon the skull, the para(|uadrate lies along the outer side of the otic region, form- ing the two sides of the pentagonal outline of the skull designated above as " paraquad- EXTLRNAL. Fig. 11. Right paraquadratiiiu Two views, x 3. INTlRNAl and (iperculuni. NECTURUS MACULATUvS. 411 rate," while the operculum Hts tightly aud exactly into the fenestra ovalis, a large lateral opening in the cartilaginous otic capsule. The most conspicuous character of the paraquadrate is the short and blunt opercular process, whicli projects from the inner edge of the curved bone at approximately the middle and tlius divides it into two nearly equal portions, the anterior or quadrate, and the postericn-, or opisthotic halves. These two halves are nearly flat, or like very shallow tioughs, the planes of which are set nearly at right angles to one another; and when in place, the anterior portion is placed neai'ly perpendicularly to the skull over- lapping the quadratum along the side, while the posterior portion is nearly horizontal and covers the outer part of the dorsal surface of the opisthotic. The paraquadrate is always connected with three bones and may possibly come in contact with two more. By its opercular process it forms a definite articulation with the columellar process of the operculum, and its two flat portions are applied to the outer sur- face of the quadrate and opisthotic. Aside fi'om these, its anterior and posterior ends may touch the outer corners of the palato-pterygoid and parietal respectively. If an isolated paraquadrate be held so that the opercular process is directed downwards, it is in its normal position and the position of the planes of the anterior and posterior portions will serve to locate it. The operculum fits something like a stove lid into the fenestra ovalis, an oval open- ing in the cartilaginous otic capsule. It consists of a flattened oval base or body bearing upon its outer surface an irregular columellar jjrocess. By means of this process it articu- lates with the opercular process of the paraquadrate and normally touches no other bone, although in old animals the pro-otic bone may enlarge sufficiently to come in contact with its anterior edge. The columellar process is directed upwards and a little forwards, and will thus give the proper orientation for the bone. The homologies and, consequently, the nomenclature of these two bones have been a matter of nnich uncertainty aud varient treatment among authors. For the first of these I have selected the term '' paraquadratum " on the authority of Gaupp, who has proposed it as at least a provisional term to indicate the dermal encasing piece associated in the amphibians with the quadrate. He apparently inclines to the belief that this element may prove homologous with the mammalian tympanicum, a term by which he designates the piece ill his revision of the " Anatomie des Frosches." The operculum has become so universally identified with the stapes of higher forms that in the first writing of the manu- script for this wi. — This consists of a series of sixteen pieces, all but one being entirely cartilaginou.s, and representing four of the original visceral arches. Their arrangement is so easily seen from plate 65, figure 12, that a verbal description of the parts would seem almost superfluous. The system is seen to contain two median pieces, universally designated as the first and second basibranchials, and referred to the first and second branchial arches respectively, of which they form the middle pieces or copulae. Of these, the second is ossified in the adult and its free posterior end usually terminates in a rounded extremity, although an occasional indix idual shows a division at the end into a two or three forked form, such as occurs normally in Siren. The liyoid arcli, which is attached to the anterior end of the first basibranchial, consists of two pieces, an inner hypohyal and an outer ceratohyal. The first branchial arch is the best devel- oped of all the branchial arches, consisting of two nearly equal pieces, cerato- and epi-branchiale 1, the first of which is directly connected with both the first and second basibranchial and with its opposite. The second Ijranchial arch consists of a smaller epibranchial, and a rudimentary ceratobranchial, reduced to a nodule of cartilage lying upon the inner side of the tUstal end of the first ceratobranchial. An epibranchial smaller than the previous one is the only remnant of the third branchial arch. In hfe the distal ends of tiie three epibranchials support the external integumcntal branchiae and furnish attachment for some of their muscles, a circumstance which has often misled investigators as to the true homology of these ]iurely integumental organs, since the location suggests a definite phylogenetic relation to the internal gill system. In the intervals between these epibranchials there occur, even in the adult Xecturus, two NECTtJRUS MACULATtJS. 423 open gill slits guarded by rudiments of gill rakers, much as in the Axolotl, and as these occur, the one between the first and the second arches, and the other between the second and the third, and consequently in the intervals between the integumental branchiae, the suggestion of connection l)etween the two systems is still more misleading. It may be remembered in this connection that there is a similar external gill upon the shoulder girdle in the Dipnoan, Protopterus, the relation of the two being wholly topographical and without morphological significance. Hence the physiological moments which have develojjed the external branchiae in this place are plainly the utilization of the gills and their muscular mechanism for support and motion, as well as the currents of fresh water which can be driven through the gill slits in such a way as to bathe the respiratory fringes. Since the attempt of Fischer ('64) to account for a fourth branchial arch by supposing that the first consists of two fused arches, no good suggestion concerning branchial arches posterior to the third had been made up to about ten years ago, since when a series of investigations by Gegenbaur (29'). Goppert ('94), and myself ('92), have rendered it probable that the larvugo-tracheal cartilages of Amphil)ia are modified portions of the fifth arch, pei-haps the epiln-anchials. A fourth arch, attached to the hyobranchial apparatus, is present in several of tlie lower Urodeles, (Siren, Amphiuma, Crypto- branchus) , and its apparent absence in Necturus has awakened some little speculation. The rudiment of this was finally discovered by Goppert, who found it to consist of a raphe of connective tissue, separating two muscles normally belonging to the branchial system, and in which, in the larva, he discovered a few cartilage cells. This view I can corroborate by investigations upon the same point at the same time, and which had led me independently to the same conclusions previous to the appearance of the work of Goppert. This raphe is given in the figiu'e referred to (pi. 65, fig. 12), and there can now be little doubt that it represents the missing fourth epibranchial. Concerning the struc- ture of the metamorphosed fifth In-anchial arches (laryngo-tracheal cartilages) , they con- sist normally of a single pair of somewhat curved pieces, applied to the sides of the glottis and short trachea, and were first described by Henle under the name of cartilago laterahs. They are individually very variable and often have notches, foramina, or detached pieces, but consist essentially of an anterior flat piece in the form of a triangle, from the poste- rior internal angle of which depends a curved tracheal process extending posteriorly. A more careful description of these cartilages and figures of several varying forms are given in the author's article on the amphibian larynx ('96) • Suspe7isorUtJ relations of the hyoid. — Tiie distal end of the ceratohyal enters into a ligamentous connection with various parts of the skull and mandible and thus bears a close relation to the suspensorial apparatus of the mandible, a region which has such an 424 HARRIS HAWTHORXE WILDER ON . ■ i'3 >o-ischium are seen two small obturator foramina which may be used as indicative of the boundary between tlie pubic and ischiadic elements which are here otherwise unmarked. A pair of osseous areas situated in the posterior half, and which develop and increase in size during growth, plainly represent the osseous ischia. The growth of these is well marked by concentric Unes. The middle portion of the ilium is also ossified, the bone being a little curved and with a rounded dorsal, and a broad and flat ventral end. The ventral face of the pubo-ischium shows a slight muscular ridge along the middle line, and the dorsal or inner face is considerably excavated to form a pubo-ischiadic fossa for the accommodation of some of the viscera. The floor of the acetabulum is usually broken through by an acetabular foramen wliich leads into this last mentioned fossa. The lateral \aew (pi. 6-3, fig. 13) shows the manner in which the ilium is attached to the sacral rib. Instead of meeting end to end and forming a definite joint, the cartilag- inous ends of the two are prolonged and tapering and are applied to the sides of one another and held in place by firm connective tissue. The relations of this attachment to the vertebrae have been considered above under the vertebral column. In two cases which I have seen, a second ligamentous attachment appeared upon one side, extending 432 IIARP.IS HAWTHORNE WILDER ON from the ril) previous to the sacral rih to the dorsal end of the ilium; aud in one of these which 1 have had the opportunity of examining more closely, tlie sacral rih on the right is normal and attached to what is probahly the 19tli vertebra, while the sacral rib upon the left side proceeds from the next posterior vertebra (20th) . In addition to this, a strong but narrow ligament proceeds from the free end of the previous rib (19th) and inserts upon the dorsal end of the iliinn anterior to the attachment of the sacral rib. As this fragment came from a student's preparation, the remainder of which had been lost, the exact determination of the vertebrae cannot l)e made, but judging from the other cases of oblique attachment which have been reported, the numbering is undoubt- edly as given. Tliis case resolves itself into one of "oblique attachment," such as have been reported by G. H. Parker, Waite, and Bumpus, the obli({uity being dextro-sinistral (see above, under Vertebral Column) . The Free Limbs. The serial homology between the fore and hind limbs in Necturus is very striking, aud in so primitive an animal, perhaps the most primitive one possessing a cheiropte- rygium, points to a fundamental similarity of origin. It is thus of greater morphological interest than correspondences in such modified structures as the paddles of Ichthyosaurus vphere it is Ukely that the similarity is a secondary modification due to a similar method of use. This resemblance, which is apparent externally, is still more emphasized by the skeletal parts, and it seems incongruous to find such similar free limbs attached to such different girdles. Each limb terminates in four digits, the lost member being generally considered to be the first, and the phalangeal formula, 2-2-3-2, is the same in both manus and pes.^ With the exception of carpus and tarsus, which are wholly cartilaginous, the limb bones of the adult consist each of a hony shaft running through the middle, and two cartilaginous epiphyses, a slight exception being the terminal phalanges which are without epiphyses at the distal end. The shaft, or diaphysis, ossifies perichondrially, as always in the Amphibia, and forms a tubular sheatli of bone, thick and constricted in the middle of its length and tapering at the ends to thin edges, the whole mass being something like the centrum of a biconcave vertebra considerably prolonged in the direction of its length. The epiphyses always remain purely cartilaginous, and never obtain calcareous deposits as in the frog. ' On this point Cope ('89, p. 25-28) seems to liave made a singular mistake, giving the phalangeal foniuila for iV. iiiamilatus as 1—3-3-2 for the manus, ami 1-2-2-2 for the pes. For the rare Carolina form, N. punctatus, he gives the formula 2-2—3-2 for both limbs, which corresponds to the normal condition in N. maculatus and is undoubtedly character- istic of the entire genus. NECTURUS MACULATUS. 433 The limbs when in the normal resting or swimming position are directed backwards, and are held in such a way that in the hind limbs the soles face inwards, while in the fore limbs the dorsal surface of the manus is ventral, and the palm dorsal. This is apt to cause considerable difficulty in orienting the parts, but if the action of the limbs be watched in a living aninud it will be seen that this position is due, not so much to a torsion, as to a swinging of the entire liml) at the shoulder. The position assumed by the fore limb is the easier to understand, and in this it is evident that the limb when extended forward as in walking, rests with the palm down and the dorsal surface of the manus up, but that when the entire limb is swung from the shoulder so as to change its direction and point backwards, the positions of palm and dorsum are necessarily reversed. In the hind limb there is some tendency to counteract this by a torsion of the limb about its own axis and thus in a trailing hind foot the sole is turned somewhat inward. Humerus. — The humerus, like the other long bones of the limbs, consists of an osseous shaft and two cartilaginous epiphyses. The usual cylindrical shape is retained only at the middle while the ends are both strongly flattened, and at right angles to one another, the proximal end being flattened laterally, and the distal end dorso-ventrally. The most prominent jjart of the proximal epiphysis is the head, which fits into the glenoid fossa of the shoulder girdle and forms the characteristic ball-and-socket joint. It is sub- spherical in shape, and is slightly affected by the general flattening of the entire region. Its ventral face is prolonged into a sharp ridge which is continued by the osseous diaphysis and forms one of the most distinctive features of the bone. This is the crista ventralis (crista deltoidea of Ecker) and .serves for the insertion of most of the ventral shoulder muscles. This crest is highest near the junction of cartilage and bone and rapidly recedes, so that at the middle of the diaphysis no trace remains. The distal end, which is broadened laterally and flattened dorso-ventrally, bears an extensive median furrow running around the end and up both surfaces, and dividing it into two masses which may be distinguished as the external (lateral) and the internal (median) condyles, although they include parts which in higher forms are distinct from the condyles themselves. The external condyle is somewhat the larger and is ball-shaped, fitting into the socket in the head of the radius. It also serves as a point of origin for the extensor muscles of the forearm and hand. Having these two functions, it plainly corre- sponds to both the external condyle and the capitulum of higher animals (epicondylus medialis and eminentia capitata of the frog ; Gaupp) . The internal condyle is more nearly the exact homologue of the part of that name in higher forms as it gives origin to the flexor muscles of forearm and hand, but does not participate as directly in the formation of the elbow joint. The groove between the twcj condyles lies in the greater sigmoid notch of the ulna, and the olecranon of the ulna and 434 HARRIS HAWTPIORNE WILDER ON the capitulum of the r.nliu.s fit respectively into its dorsal and ventral continuations (luring forced extension and flexion of the forearm. These slight grooves or depressions, of which the ventral is, perhaps, a little stronger than the dorsal, are thus the first sugges- tions of the olecranar and cubital fossae which develop in higher foi'ins. The humerus is distinguished from the femur by its sharp crista ventralis wiiicli pro- jects farther than that of the femur and is differently shaped. This same feature, which marks the ventral side, and the large and spherical external condyle serve to orient the humerus. Femur. — The general shape of the femur is like that of the humerus, Init without much flattening at the proximal end. Here it shows two projections for muscular attach- ment : ( 1 ) a distinct process, mostly formed by bone, but tipped with a cartilage which in the adult is independent of the main epiphjsis, and (2) a ridge or crest upon the side of the head, involving also a part of the shaft. It is somewhat difficult to compare these two distinct features with the single crista ventralis of the humerus, but in accordance with position it would seem that the bony process corresponds most closely with that part, and may thus bear the same name, while the ridge which lies more upon the external lateral aspect may be designated as the crista lateralis. As this crest is similar in appearance, though not in position, to the proximal cartilaginous part of the crista ventralis of the humerus, it is possible that these two parts found in the femur correspond to the single process of the humerus, and that in the former a difference in motion and consequently in muscular insertion has separated the two parts and diverted one of them from its origi- nal position. iSiicli an explanation is, however, not in accord with the almost universally greater differentiation of the anterior limb, and one would expect to find in the femur the more primitive condition. Hoffmann distinguishes in the Urodeles a single projec- tion referred to as crista femoris, a name applied by Gaupp to a similar part in the frog, but the femur of this latter animal is so unlike that of Necturus that homologies of parts are uncertain. It hence seems better to refer to the two processes found in Necturus by the two terms given above, crista ventralis and crista lateralis, terms which accurately express the j^osition of the parts, and one of which suggests a justifiable homology with the humerus of the same animal. The distal joint is imperfectly divisible into the external and internal condyles, although there is no distinct groove between them. The internal condyle is larger and longer and serves as the main point of origin for both flexor and extensor muscles of the lower leg and foot. The smaller e.Kternal condyle articulates with the proximal end of the fibula. The osseous crista ventralis, separated from the head by a notch, is sufficient to dis- tinguish femur from humerus and to mark the ventral side of the bone. This and the more projecting internal condyle of the distal epiphysis wiU complete the determination. NECTURITS MACULATUS. ^^^ AntibracMum and manus ; cms and pes. -Hhe^e partB iu the two limbs are almost iudistiuguishable from one another, as may be seen by a comparison of figures U and Vo (plate m) which were drawn from the right anterior and posterior hmbs of the same indi^idual 'by the aid of a camera lucida. Corresponding to a difference in use of elbow and knee, tlie proximal ends of ulna and radius are different from those of tibia and fibula, but otherwise the parts correspond as closely as do consecutive parapodia of a polychaet- ous Annelid. ' i ±- i The ulna shows a greater sigmoid notch and the radius a capitulum, both tor the reception of parts of the distal epiphysis of the humerus. Furthermore, these bones are a liftle longer than are the tibia and fibula. Carpus and tarsus are exact duplicates m the two limbs and consist of two proximal bones, a centrale, and three bones of the distal row. In the proximal row the intermedium is fused with the outer element (ulnareor fibulare) leaving between them a foramen for the transmission of an artery.^ In the dis- tal row digits II and III have each a distinct element, while those corresponding to IV and V Ire fused. Four digits, II-V, are represented in each case, each with a well devel- oped metacarpal or metatarsal and nine phalanges, three in the fourth digit and two in each of the others. Three phalanges in the third digit, also, is a not uncommon anomaly. "^ LiTERATUKE. ""'T.' A contribution to the study of variation. (Skeletal variatioa. of Necturus ,naculatus Raf., Jour-n. of morphol., vol. 12, p. 455-484, pi. A-C. Cope, E. D. . Q. 1 '89. The Batrachia of North America. Bull. U. S. nat. mus., no. 34, 525 pp., 119 fags., 8b pis. Fischer, J. G. m *• i q ■64. Anatomische abhandlungen fiber die Pereunibranchiata und Derotremen. 4 . fat. 1-8. ""''^y.^On the evolution of the vertebral column of Amphibia and Amniota. Phil, trans, royal soc. London, vol. 187, series B, p. 1-57, fig. 1-56. '''''92 Beitrage zur morphologie des .schadels. 1. Morphol. arbeiten, bd. 2, p. 27.5-481, taf. i:i-16. -94a. Beitrage zur morphologic des schadels. 2. Das hyo-branchial skelet der Anuren und seine nmwandlung. Mor- phol. arbeiten, bd. 3, h. 3, p. 399^38, fig. 1, taf. 18-19. .34b Beitrage zur morphologie des schadels. 3. Zur vergleicheuden anatomie der schlOfengegend am knoche.nen wirbelthier-schadel. Morphol. arbeiten, bd. 4, h. 1, p. 77-130, taf. 6-7. '96. Die anatomie des frosches. (New edition of the well known book of Ecker and Wieder.sheim.) 1896. Gegenbaur, C. ■ i t i > •92. Die epiglottis. Vergleichend-anatomische .studie. 4^-. p. 1-69, tig. 1-14, tat. 1-:.. . The artery in the hand which runs through the foramen carpale is the art. cubitalis which thus reaches the ^o^al sur- face aL is dttributed to the digits. In the foot a similar function is performed by the contmuat.on of the art. femo.ahs. 430 HARRIS HAWTHORNE WILDER ON Goppert. E. "94. l)if kelilkniifiimskulatui- der Aniiiliibit-ii. Muiplicl. jiilirb.. lid. 22, li. 1. ji. 1-78, %. 1-9, taf. 1-2. '96. Die iiiorpholoijie dor amphibiunrippeii. I'Vstschrift zuiu .siebenziasten geburt.statce v. Carl Gegenbaur. bd. 1, p. 303-435, fig. 1-10, taf. 1-2. Leipzig. '98. Del- kelilkiipf del- .\ii]pliil)ifi] uiid Reiitilieii. 1 TlH-il: .Xniphibieii. MuIIjIki]. jahrb., bd. 2(1. h. 2. p. 282-329, Kg. 1-5, taf. 8-11. : 01. BeltrSge zur vergleicheiideii aiiatomie des kehlkupfes uiid seiner umgebung, mit be.sonderer berucksic-litiguiig der Monotremeii. Aus Semoii: Zoologisclie for.scliimgsrei.se in Aiistralien und dem Malayisclieii areliipel. 4^: p. 535- 634, fig. 1-52, taf. 17-21. Hoffmann, C. K. '73-'78. Aiiiphibieii. hi lirouir.s Klassen und iirdiiuii;;eii des tliierreichs, bd. 0. abth. 2. Leipzig u. Heidelberg. Hu.xley. T. II. '74. (>a the .structure of the .skull and of the h-^'art of Menobraachus lateralis. Proc. zool. soc. London. 1874, p. 180- 204. pi. 29-32. Hyrtl, J. '65. Cryptubraiichusjapunlcus. Vienna. Parker, G. H. '96. Variation.s in the vertebral column of Necturus. Anatom. anzeiger, bd. 11, p. 711-717, fig. 1-2. Parker, W. K. '77. On the .structure and development of the skull in the urodelous Amphibia. Parti. Phil, trans, royal soc. Lon- don, vol. 107, pt. 2, p. 529-597, pi. 21-29. (In the above article, the description of Proteus is the one of e.special value in this place.) Piatt, J. B. '97. The development of the cartilaginous skull and of the branchial and hypoglossal musculature in Xecturus. Mor- phol. jahrb., bd. 25, h. 3, p. 377-464, pi. 16-18. Stohr, Ph. '80. Zur eiitwieklung.sgeschiohte des urodelenschiidels. Zeit.schr. f. wissenschaftl. zool., bd. 33, h. 4, p. 477-526, taf. 29-30. Waite, F. C. '97. Variations in the brachial and lumbo-sacral plexi of Jfecturus maculosus [^ mnculatus] Rafinesque. Bull. nius. comp. zool., vol. 31, p. 69-92, pi. 1-2. Wieder.sheim, R. ■77. Das kopfskelet der Urodelen. Moi-phol. jahrb., bd. 3, h. 3, p. 352-448, fig. 1, taf. 19-23. Wilder, H. H. "92. Studies in the jiliylogenesis of the larynx. Anatom. anzeiger, bd. 7, no. 18, p. 570-580, fig. 1-3. '96. The amphibian larynx. Zool. jahrb., abtheil. f. anat. u. ontog., bd. 9, h. 2, p. 273-318, fig. A-D, pi. 19-21. Winslow, G. M. '98. The chondrocranium in the Ichthyopsida. Tufts college studies, no. 5, p. 147-201, pi. 1-4. NECTURUS MACULATITS. 437 Explanation of Plates. (The outlines of all the figures were drawn with a camera, three times the natural size in the niajoi.'ty of the cases. Since, however, the originals varied considerably in size, the resulting figures cannot be considered as proporlionat*! to one another. The figures of the chondrocranium, for example (pi. (iS, figs. 4, 5), were drawn from a very small specimen and enlarged four times, but the resulting figures are almost exactly comparable with those of the entire skull (pi. 63, figs. 2, 3) drawn from a medium sized specimen at a magnification of but three diameters. A large skull at two diameters would give about the size vi figures 2 and 3.) ABBHEVIATIONS USED. (The abbreviations given in the following list include tho.se ujsed in the figures, as well as those emploj-ed in the text at various places.) 1. Bones. A — atlas. ANG — angulare. BB — basibranchiale 2 CS — costa sacralis. DENT — dentale. EXO — exoccipitale. F — frontale. FB — fibula. FM — femur (diaphysis). H — "1st haemal arch vertebra" (see text). HM — humerus (diaphysis). IL — ilium. IS — ischium. MC — metacarpalia. MT — metatarsalia. 00 — opisthot i cum . OP — operculum . P — parietale. PB — parabasals. PH — phalanges. PMX — premaxillare. PC — pro oticum. PPT — palato-ptcrygoideuui. PQ — paracjuadratum. Q — quadratum. R — radius. S — sacriun. SC — scapula. SPL — spleniale. T — tibia. UL — ulna. V — vomer. 2. Other Designations. Abbreviation. Name. a. b-o. — arcus basi-occipitalis. art. — articulare (Meckel's cartilage). a. s-o. — arcus supra-occipitalis. b. b. 1. — basibranchiale 1. br. — bronchus. c. — carpalia. caps. nas. — capsula nasalis. caps. opt. — capsula optica. caps. ot. — capsula otica. cart. lat. — cartilago lateralis. cart. Mk. — cartilago Meckelii. 0. b. 1-2. — ceratobranchiale 1 et 2. cent. — centrale. c. h. — ceratohyale. cond. ext. — condylus externus. cond. int. — condylus internu-s. cond. oc. — condylus occipitalis. Location. H and F.\I . H and FM. EXO. Abbreviation. Name. cor. — coracoideum. cr. lat. — crista lateralis cr. mus. — crista muscularis. or. temp. — crista temporalis. cr. ventr. — crista ventralis. e. b. 1-4. — epibranchialia 1-4. epiph. c. s. — epiphysis costae sacralis. epiph. il. — epiphysis ilii. f . acet. — foramen acetabulare. f. carp. — foramen carpale. f. cor. — foramen coracoideum. f. mand. — foramen mandibulare. f . nbtur. — foramen obturatorium. f. sty.-m. — foramen stylo-mastoideum. f. tars. — foramen tarsalc fib. — fibulare. fn. oval. — fenestra ovalis. Location FM. Pelvic girdle. F. H anHW MEMOIRS OF THE BOSTON SOCIETY OF NATURAL HISTORY VOLUME 5, NUMBER 10. THE COMPARATIVE ANATOMY AND PHYLOGENY OF THE CONIFERALES. PART 1. — THE GENUS SEQUOIA. By EDWARD C. JEFFREY. BOSTON : PUBLISHED BY THE SOCIETY. November, 1903. m 10. The CoMi'AiiATivE Anatomy and Puylogeny of the Coniferales. Pakt 1. — The Genus Sequoia.^ By Edwakd C. Jeffrey. (He-.wl Apiil 15. 1903.) Introditctiox. In the present and following memoirs, it is my intention to describe certain featm-es of the anatomy of the Coniferales which appear to be of interest. The actual state of om- knowledge of the morphology and history of the group is not sufficient to justify much certainty as to its classification, and conseiiiiently additions from any standpoint are likely to be of value. The prevailing views as io the relationship of the various orders of the Coniferales are l)ased almost entirely on reproductive characters, and valuable as these must always be, they constitute, nevertheless, but a single line of evidence. The study of the anatomy of the older groups of C4ymnosperms has done so much to clear up the question of their affinities that it does not seem unreasonable to expect that a good deal should be learned from investigations carried out on the same lines in the case of the Coniferales, the prevailing Gymnosperms of the present day. It is to be anticipated that the results of such investigations will serve to correct and supplement the conclusions drawn from the study of the reproductive organs alone. The existing Sequoias are chosen as the subject of the first memoir, both because of their interest as the sole survivcjrs of a genus which once tiourished in many species throughout the entire northern liemisphere, and because investigations, already some- what extensive although as yet incomplete, make it apparent that the genus Sequoia presents a striking example of those rare and important forms which so infrequently per- sist as links of transition between distinct and ditferent natural orders of the present day. The Stem of Sequoia r/igantea. Figure 1, plate 68, illustrates the structure of the wood in Sequoia gigantea as it appears in a transverse section of the heart of an old stem. There are three annual rings represented in the figure. In contrast to S. semperviren.% to be described later, the 'Harvard Botank-al Memoir.s. — Nci. 7. 442 EDWARD C. JEFFREY OX autumnal traclieids form a very narrow zone in each annual ring of growth, and the wood consequently lacks the strength which is characteristic of the latter species. The radial rows of tracheids are interrupted at intervals, especially in the autumnal region, hy the resin cells which are so constant a feature of the wood of the Taxodineae and Cupressineae. As has been pointed out by PenhalloAv (Generic characters of North American Taxaceae and Coniferae, Proc. and trans, roy. soc. Canada, 1 896, series 2, vol. 2, p. 33), the resin ducts, found so frequently in the wood of the Abietineae, are absent in the mature ligneous cylinder of -ures present extreme conditions in the modes of occurrence of resin canals in the wood of the fructiferous scales. Where the ducts are least alnindant they are confined to the lower side of the scale as in figure 11, plate GO, and form a single sei'ies. They may also extend as a single series to the upper side of the scale. When the system of ducts is double, it may be double on the lower side of the scale only, or ou one or other wing of the scale as well, or linally as in figure 12, plate liO. the double sei'ies may extend all ANATOMY AND PIIYLOGENY OF THE CONIFERALES. 445 arouud the medulla. Whenever a doiihle system of ducts extends more or less com- pletely around the wood of the scale, the series nearer the medulla is always complete, whatever may be the case with the more external series. The more complex arrange- ments of the resin canals just described are more often found in the upper scales of the cone. The outer system of ducts, unlike the inner one, never extends down into the axis of the cone, although it may pass far up in the bundles into wliich the fi))rovascular tube of the base of the scale breaks above. In figure 13, plate 69, is seen a transverse section of the upper liroad portion of the fructiferous scale. The scale is covered on both the upper and the lower surfaces with a layer of periderm. In the fundamental tissue of the scale are numerous large resin passages as well as numerous sclerenchymatous cells. There are present two systems of fibrovascular bundles oriented in opposite directions, of which the upper series is less well developed and consists of somewhat smaller bundles. Along the upper margin of the lower set of bundles, which are the better developed, can be seen small, light dots which mark the position of intrafascicular resin ducts. These are continuous with those described above as occurring in the lower portion of the woody skeleton of the scale. Resin canals are much more commonly present in the lower series of bundles of the flattened upper part of the fructiferous scale than they are in the upper series, possibly on account of the greater robustness of the fornjer. Figure 14, plate 69, shows a portion of the same section more highly magnified. The structure of tlie fundamental tissue can be more clearly seen. It consists of parenchymatous elements, of long scler- enchymatous elements present iu cross section, and of large resin passages. Within the inner boundary of the woody tissue of most of the lower bundles can be seen one or more resin ducts. These are absent from the upper bundles. Figure 15, plate 69, represents another part of the same section. The fundamental tissue presents no difference from that shown in the preceding figure ; but the bundles which belong to the lower series, towards the margin of the scale, are obviously united by strands of tissue running from their inner borders. The tissue in question is made up of transfusion cells. The smaller terminal bundles of the extreme upper portion of the fructiferous scale of S. nigantea are all more or less completely united at their inner borders by transfusion cells. The bundles likewise frequently terminate in transfusion tissue as well. Occasion- ally towards the lower part of the course of the bundles, as they become imited into the fibrovascular tube of the base of the scale, the enormously developed transfusional borders of the bundles bend inwards and fuse more or less completely together, giving rise to a pecuhar pseudomesarch type of Inmdle such as is shown in figure 16, plate 69. In this fio-ure two resin canals are to be seen in the secondary wood. Subtending the part of the secondary wood containing the two resin ducts, is a mass of parenchyma which is 446 EDWARD C. JEFFREY OX enclosed incompletely on tlie opposite side by wing-like extensions of the secondary xylem. These are in tin-n completely covered by a thick zone of very dense transfnsion tissue. The phenomenon just described is not of very common occurrence and in all probability no very great morphological importance is to be attached to it. The Seedling of S. r/ir/antea. Figure 17, plate 70, reproduces a transverse section of the woody portion of a five year old seedling of *S'. giganiea, collected by Prof. Asa Gray in the famous Calaveras grove of Big Trees, during his visit to California in 1872. I owe this duplicate specimen to the kindness of my colleague. Prof. B. L. Robinson, curator of the Gray herbarium. Four annual rings are shown in the figure. The resin cells which are so conspicuous in the wood of the adult stem are much less strikingly present in the seedling, and resin ducts are entirely absent even from the first annual ring. Through the kindness of Dr. Joseph L. Goodale, 1 have had tlie opportunity of examining several other seedlings of S. (jlganten, grown on his estate at Ipswich. In none of these did 1 lind any indi- cation of the presence of resin canals in even the first annual ring of woody growth. Effects of Wounds on the Woody Tissues of *S'. glgantea. Figure 18, plate 7(1, represents part of a transverse section of a wounded root of S. glgantea, in which tlie wounded area has become completely callused over. Towards the right in the figure, may be seen a mass of callus tissue. In the ring of growth just below the callus, is to be made out a long row of traumatic resin ducts stretching completely across the figure. The annual ring containing the resin canals, although axial to the callus, was formed subsequently to the wounding of the tissues, as was made out by examining the whole line of injury. The resin ducts are quite similar to those occurring normally in many of the Abietineae, and are generally surrounded by but a single layer of cells. Of these cells some are normal glandular cells, such as usually surround the lumen of resin canals where they occur in the wood of the Abietineae, while others are " resin cells," and are distinguished by their thick and strikingly pitted walls. In figure 19, plate 70, is represented part of the outer margin of the wood in a transverse section of the peduncular portion of the cone of S. glgantea. Very large resin canals appear along the inner border of the vernal wood in the last annual ring. These are surrounded by secretory cells ; but as the figure was made from dry material the latter have almost completely collapsed. The formation of true resin canals in this case was due to the same cause as in the root just described above. I have seen a large number of instances ANATOMY AND PHYLOGENY OF THE CONIFERALES. 447 of the formation of traumatic resin canals in the wood of both the root and the stem of 8. gigantea and consequently am of the opinion that it is quite a usual result of injury. It should be added, however, that the formation of parenchymatous wood containing a large number of resin cells and ordinary parenchyma cells is even more commonly pre'sent in the case of wounds. This is especially the case with large exposed wounds on the aerial portions of the stem, where there is much necrosis and drying out of the woody tissue. In smaller wounds, however, where there is not too great an exposure of the ligneous cylinder to desiccation, the formation of the traumatic resin passages described above is very common. It should be noted finally that the traumatic resin canals of S. gigantea are formed in the vernal wood and in this respect are in contrast to those occur- ring in S. sempermrens under similar conditions, which, as will he shown later, make their appearance in the autumnal wood. I have found examples of the formation of resin canals iu the phloem of 8. gigantea, as well as in the wood, and as the result of a similar cause. I have discovered no instance of the occurrence of resin ducts in the fibrovascular cylinder of this species, except in the first year's growth of vigorous young branches of adult trees and in the axis of female cones (as described in earlier paragraphs) , which could not be clearly traced to a previous injury. It seems extremely probable that the formation of traumatic resin canals in 8. gigantea is to be regarded as a case of reversion to an ancestral condition, especially in view of the mode of occurrence of normal resin canals in certain instances as described above. The arguments in favor of this view, how- ever, are best deferred to a later stage. Traumatic Resin Canals of the Abietineae. It seems necessary in the meantime to refer preliminarily to certain other facts of a similar nature which have been made out in the case of the Abietineae, in a series of researches of which the present investigation forms a part. It has long been known that resin ducts are generally absent in the wood of the Abietineous genera, Abies, Tsuga, and Cedrus, and that they are replaced in many instances by resin cells. For the present the first-named genus will alone be considered; for as I hope to show subsequently, the other two genera resemble it very closely in the features which are of interest in this con- nection. Abies firma is described by Prantl (Engler u. Prantl, Nat. pflanzenfamilien, Coniferae, 1889, p. 37) as differing from the other species of Abies in normally possessing resin ducts in its wood. Penhallow {op. cit.) has more recently described the presence of resin canals, occurring in isolated annual rings of Abies nobilis and Abies bracteata. I have been able to confirm these observations in the beautiful series of sections of North American woods pubUshed a few years ago by Professor Penhallow. The resin ducts 448 EDWARD C. JEFFREY ON occur in long tangential rows in l)()tli the last-named species. T have myself examined a number of species of the genus Abies, and have found resin canals of verv frequent occurrence under conditions to be more fully descrilx'd on another occasion. For the present, however, it may be stated that re.sin ducts are extrenu'ly apt to be present in the female reproductive axis of various species of Abies, even when the}' are quite absent from the woody tissues of the ordinary vegetative stem. For example, in Abies cjrand'is^ according to Penhallow, there are no resin ducts present in the wood. Figure 20, plate 70, shows the general structure of the woody axis of the upper portion of the female cone of A. grandis. The specimen from which the figure was made, was secured at the Gray herbarium, and as a consequence the tissues have suffered a good deal from long desicca- tion. Nevertheless, indubitable resin ducts can be clearly made out in large numbers in practically the whole circumference of tlie woody cylinder of the cone. They are of quite the normal type and are surrounded l)y glandular cells which still retain the remains of their protoplasm. The section through the small upper end of the cone axis was chosen because it permitted of showing the structure of the whole of the ligneous portion of the tissues of the cone on a sufficient scale of magnification to make clear the presence and mode of distribution of the resin canals. In figure 21, plate 70, is seen a similar view of the woody tissues in the cone of Abies balsamea. This species is devoid of resin ducts not only in the wood of the vegetative axis but also in that of the cone. The figure in this case was made from material wliich had been properly presei'ved. Figure 22, plate 70, is made from a section through an iiijni-ed root of a small tree of Abies balsamea growing in the Botanic garden of Harvard university. The figure includes all the xylem as well as a portion of the phloem of the injured root. There is an interruption of con- tinuitv in the latter tissue on the lower side, due to an incised wound which was made in all probability by a spade used in digging the soil about the tree. The woody tissue is likewise interrupted in the same region as the phloem, and on one side the last annual ring is separated for some distance from the tissues below. There is a considerable forma- tion of resinous tissue along the inner margin of the last annual ring on both sides of the wound, which takes the form of resin cells. Farther away from the wounded portion, on the left, the resinous tissue gives place to a tangential row of resin ducts continuous through almost half the circumference of the root, and passing on tlie right into a narrow zone of resin cells, wdiich are in turn continuous with the thick mass of resinous tissue on the immediate border of tlie wound. The center of the root is occupied by a resin duct surrounded by resinous cells, such as is conunonly found in the axial wood of the root in the genus Abies (de Bary, Comp. anat., 1884). My investigations on this genus, although not yet complete, show that resin canals occm" very frequently in the female reproductive axis, even when they are (juite al)sent from tlie wood of the vegetative stem ANATOMY AXD PIIYLOGENY <^F THE CONIFERALES. 449 and from the root as well, except in the axial primary wood as just mentioned above. In all eases where 1 have been able to make the experiment, however, I have succeeded in l)ringiug abont the formation of resin canals as a result of injury, in the wood of species of Abies which are normally without them, even in their reproductive axis. It is interesting in this connection to note that certain fungous diseases causing iniury to the wood of species of Abies produce the same result. It seems necessary to record the traumatic reactions of the woody tissues of the genus Abies because, as I shall attempt to show at the end of this essay, they supply an interpretation of the similar phenomena in the case of Sequoia. The Leaf of S. (jirjoiited. In figure 23, plate 70, is seen part of a section tlirough the base of the leaf of »S'. giganfea. In the center of the figure lies the leaf trace fianked by the two lateral win^-s of transfusion tissue, which are so characteristic of the lower part of the foliar bundle in Sequoia and its allies. Above and below the leaf trace are masses of collenchyma- toid tissue. The feature of greatest interest in the figure is, that contrary to other described coniferous leaf traces, the foliar bundles of S. gir/ai)fea contain a resin duct. The duct is (|uite of the normal type and is surrounded by a single, almost complete row of resiniparous cells. In some cases, however, as is often found in tJie resin canals of the Sequoias, the parenchymatous lining of the canal is far from being contiiuious, and the tracheids as a result often abut directly on its lumen. It must not be supposed that resin ducts occur in all the leaf traces of S-. gigantea, for this is not the case. They appear only to be present in the bundles of the very lai'ge leaves of exceptionally vigorous branches of mature trees (i. e., trees which have already ripened seed) . All the material which I have, showing this feature, came horn the Gray herbarium of Harvard univer- sity; but in spite of the necessarily bad condition of preservation consequent on its origin, there seems to be no reasonable doubt as to the nature of the canals, which I have described a))ove as resin ducts. Tlie longitudinal range of the resin ducts of the foliar bundles of the largest leaves in mature trees of Sequoia gigantea is quite limited ; for they appear only after the leaf trace has passed quite out into the cortex of the branch, and indeed after it has traversed a cousideralile part of its upward and outward course. There is as a consequence no communication between the resin ducts of the first annual ring of wood in the branches and those appearing in the leaf traces. Like the other modes of occiu-rence of resin canals described above, there is an entire absence of correla- tion with other similar tissues. The resin ducts of the leaves disappear again very shortly 450 EDWARD C. .TP:FFKEY ON after the leaves have emerged from the surface of the branches, so, as has just been stated above, tlic longitudinal coui-se of the resin canals of the leaf traces, where they occur, is ver^• short indeed. 'The Stem of Sequoia sem])ervirenf<. Peuhallow (oj). cit.) has noticed the occurrence of continuous tangential rows of what he terras " imperfect resin ducts" in the wood of the old stem of S. sempervirenR. The phenomenon seems to be extremely rare, for I have found very few examples although a large number of different specimens of the wood of this species has been examined in this connection. Professor Penhallow has been so kind as to send me a very good example illustrating this peculiarity, and as it is much more striking than any other I have seen, all the accompanying figures of the mature wood of S. semiMrvirena are made from this material. In figure 24, plate 70, a part of a transverse section of the wood of *S'. sempervirens is represented under a low magnification. There are fovir annual rings present in the figure. Mingled with the tracheids in all the four woody rings are numerous resin cells, such as have been described above in *S'. gigantea, and such as occur commonly in the other Taxodineae. The autumnal wood in S. semper- virens forms a much thicker zone than in S. gignntea, which is the cause of the greater weight and strength of the wood in the former species. In the second .annual ring from the top of the figure are to be seen the resin ducts first described for *S'. sempervirens by Penhallow (op. cit., p. 39, pi. 6, fig. 2). They are obviously situated in the autumnal wood and in this respect present a marked contrast to those of S. gigantea described in the foregoing paragraphs, for in the latter species they occur in the vernal portion of the annual ring. In their distribution the resin canals in the present instance resemble those formed as the result of injury in S. gigantea, species of Abies, etc., and form a continuous tangential zone, such as is characteristic of traumatic resin canals. Figure 25, plate 71, shows a portion of the annual ring containing resin ducts more highly magnified. There is obviously a sharp transition from the autumn wood to that of the following spring in the size of the tracheids and the thickness of their walls. There are numerous resin cells on the outer margin of the autumnal wood. Farther inwards, the autumnal tracheids give place to parenchyma cells, which, on account of the fact that the material is from the heart wood of an old tree, are quite devoid of protoplasmic contents. They are unmistakable, however, since their walls are composed of cellulose and stain a deep blue with haematoxylin. About the lumina of the resin ducts, the parenchymatous cells are as a rule strongly pitted and closely resemble the resin cells of the medullary rays in certain Conifers. ANATOMY AND PHYLOGENY OF THE CONIFERALES. 451 In figure 26, plate 71, is shown a transverse section of a young branch of S. semper- rirens from material sent to me by Dr. A. A. Lawson of the Botanical department of Leland Stanford university. The bases of four leaves clearly appear on the margin of the figure. These originate from the branch by a flat base in contrast to the rounded mode of origin found in >S'. glgantea. In two of the leaves there are obviously three resin canals in the mesophyll, another point of contrast to S. r/igantea and most of the other Taxodineae and Cupresslneae, where there is as a rule but a single resin duct in the parenchyma of the leaf, and immediately under the fibrovascular biuidle. The material from which the illustration has been made was cut and preserved in California on the 2d of May. The growth of the present year's ring of wood has begun and has already reached a considerable thickness. Bi'anches of S. glgantea cut from trees at the same spot and at the same time show scarcely any signs of the commencement of cambial activity. Tlie slowness of initiation of cambial activity in the Big Tree is no doubt one, at least, of the causes of its greater hardiness. There are no resin ducts to be seen in the wood of the young branch, appearing in transverse section in the figure, and in this respect the illustration might stand for any branch of S. semperviirens ; for I have not found even in the most robust ramifications of the mature trees of this species any indica- tion of the resin canals, which are so often present in the first annual woody ring of S. gigantea. Traumatic Resin Ducts in S. semjjervirens. In some of the specimens sent me by Dr. Lawson from the arboretum of Leland Stanford university the phenomenon of fasciation was present. As this feature of S. semper vir ens has recently been fully described by Pierce (Studies on the Coast Redwood, Cal. acad. sci., 1901), it will not be necessary to refer to it here. The wood in most of the fasciated specimens was quite normal as regards the absence of resin canals; but in the subterranean portion of a dead branch which had taken on the flattened mode of growth so characteristic of fasciation, numerous resin ducts were found in tangential rows. The shoot in question had oljviously been injured and the appearance of resin canals is doubtless to be correlated with the diseased condition of the tissues. Figure 27, plate 71, is made from a section through this branch. There are two annual rings present and it is in the first of these that the resin ducts are to be seen. The ducts are in tangential rows and are situated in the autumnal wood just as in figure 25, plate 71. In figure 28, plate 71, are represented some resin canals from anotlier section of the same material, highly magnified. The resin ducts are obviously surrounded for the most part l)y cells still containing protoplasm and a nucleus, although in some cases the traclieids 452 EDWARD C. JEFFREY ON almt directly on the lumen of the resin canal. The stnictnre of the ducts shown in the figure is ciuite typical of the resin passages I have found in the Sequoias in general, it is a fact of considerable interest in the present connection, that the resin ducts first described by Penhallow for the wood of the old stem of S. sempervirens occur in the same tangential rows which are found in the obviously injured stem of the species under discussion, and under similar circumstances in the Ablet ineae as well. It is often the case that traumatic resin canals extend far above and below the actual spot of injury and it accordingly seems extremely pi'obable that the rows of imperfect resin canals found in the otherwise quite normal fragments of wood of *S'. sempervireMS are really due to an injury above or below the region from wliich the pieces of wood have been taken. The Repkoductive Axis of S. senqjercirens. ■ In figure 29, plate 71, is represented the fibrovascular cylinder of the lower third of the reproductive axis of S. sempervirens. Although the cone from which the section was made had long shed its seeds, and had assumed an almost black hue from long exposure to the weather, there are obviously no indications of annual rings in the photograph. While the absence of annual rings does not absolutely prove that there are no additions to the secondary wood of tlie reproductive axis after the first year, still it appears very probable from the state of affairs in the cones of the other living species of Sequoia that such is the case. This view of the matter is further strengthened by the occurrence of perfectly norn)al animal rings in the vegetative organs of S. sempervirens. The question can, however, only be finally settled by the study of the growth of cones in the field. There are no annual rings in the peduncular portion of the cone of the species under consideration and in this respect it also presents a contrast to S. f/ir/antea, where, as has Ijeen described above, there are numerous annual rings in that region of the reproductive axis. Further, resin ducts are entirely absent from all parts of the wood of the cone of >S'. sempervirens. Figure 30, plate 71, shows the structure of a cross section through the base of a cone scale of this species. The dense wood of the tubular central cylinder of this portion of the fructiferous scale shows no evidence of the presence either of the annual I'ings or of resin ducts, which are such notatjle features of the cone scales of S. {/i(/intfen. The specimen shown in figure 30 is quite typical in these respects; for I have examined a number of cones from different sources, without finding any examples of the occurrence of either of these structures. In figure 31, plate 71, appears a portion of a transverse section of the upper third of the cone scale of S. semper clreiis. The large bundles along the lower side of the figure belong to the lower series. They are very much larger than those neai- the upper surface of the scale and are inverseh- oriented. ANATOMV AND IMIVLOGENY oK THE COXIFEliALEt^. 453 lu the .species under cuii.sideratiun there is a very iiiueh greater relative rediurtion of the upper series of bundles than is the case in S. i/if/untea. The commissures of transfusion tissue, which are so marked, especially in the lower bundles of the cone scales of the latter species, are much less well developed in the Redwood. The fibrovascular bundles of the fructiferous scales of S. xexiparinreiDi show lu) annual increments of growth and never contain resin ducts. TuK Hoot of the Sequoias. Figure 32, plate 71, illustrates the structure of a small root in /S'. (jUjiuitea. It is obviously pentarchous in its organization and very much resembles a I'oot of Phi its strohus or some other Abietiueous species with large polyarch roots. The protoxylcm groups, however, which occupy the apices of the five ravs of the primary wood, differ from those of species of Pinus, (dc, in not embracing resin ducts. Although the roots of the species under consideration are generally pentarchous, examples are not infrequently found in which there are only four rays of primary wood. This state of affairs also occurs in P'uuis strobKn. The primary root of all seedlings of .V. (jujanted which I have exam- ined is of the tetrarchous type. I luive never found resin canals present in the secondary wood of this species except as the result of injury. The root of *S'. sempervirens is so similar to that of N. (jUjautfa as scarcely to merit a separate description. The symmetry of the root is. however, almost always tetrarchous and the various histological elements are .somewhat larger than in the latter species. C0NCLU.SIOXS. In the foregoing paragraphs, attention has been called to the occurrence of re.sin ducts, under certain definite conditions, in the wood of Sequoia. In *S'. yujantea, which in all probability is the more primitive of the two surviving .species, resin canals are con- stantl}' present in the wood of the peduncle, of the axis, and of the scales of the female cone. They also frequently occur in the first aniuial ring of the more xigoi'ous l)ranches of adult trees. Resin ducts likewise are sometimes found in the leaf traces of the larger leaves of well nourished, mature individuals. Finally, it is possible to bring alxiut the formation of resin canals in tangential rows as the result of injury to the woody cyhnder of the root .stem and cone of S. (/lijuiitcd. The I'csin ducts occurring in thi' various situ- ations cited above, form entirely separate systems which do not comnuuiicate in anv wav with each other. In S. sempervirens, in contrast to the .species just referred to, there are no resin canals in the woody tissues either of the reproducti\e organs, or of young 454 EDWAKI^ C. JEFFREY ON branches, or even of vi^oi-ouH leaf traces. In ;S'. .sempercirens, resin ducts appear only as tangential rows iu isolated annual rings, probably in all cases in response to injury to the tissues of the wood. The occui-rcuce of resin canals in the reproductive axis of S. (/Ii/(infe(( is iu all proba- bility to be regarded as an ancestral feature. It is significant in this connection that certain species of Abies, which have no I'csin (hicts in tiic wood of their vegetative organs, retain tlieiu in the ligneous cylinder of their cones, e. (/., A. r/raudls, A. iiohi/is. etc., etc. Tn the case of tliese species the presence of resin ducts as a general feature of structure of the wood in the order to which they belong, justifies the conclusion that the occurrence of resin canals in the wood of the female reproductive axis is an ancestral character, which has disappeared in tlie wood of the vegetative stem. A parallel case is presented by the peculiar mesarch bundles found by Dr. Scott in the peduncle of the cones in certain Cycads (The anatomical characters presented l)y the peduncle of Cf/cadaceae, Ann. bot., 18'.»7, vol. 11). Bundles of this nature were present in the medullary crown of the vege- tative axis of certain of tlie primitive fossil Gymuosperms and of the Cycadofilices. In the living Cycads, mesarcli bundles have disappeared in the vegetative stem, but are some- times retained in the re])r(jductive axis and quite generally iu the vegetative and repro- ductive leaves. In *S. (jlrjantea, resin ducts retained in the wood of parts of the female cones, likewise occasionally occur in the leaf traces as well, thus presenting a striking parallel to the mesarch bundles of the Cycads, in the manner of their distribution. The presence of resin canals under certain (juite definite conditions in the first annual ring of tlie branches of S. (j\(jantef)i.s, showing the preseuce of a tangential row of resin ducts. X 35. PLATE 71. Fig. 25. Part of the last section more highly magnified, showing the structure of the wood and the resin ducts. X 100. Fig. 26. Transverse section of a young branch from an immature tree of S. sempervirens. X 30. Fig. 27. Transverse section of part of an injured stem of S. sempervirens, showing the presence of tangential rows of traumatic resin ducts in the autumnal wood. X 50. Fig. 28. Transvei'se section of another similar .specimen, .showing details of the structure of the traumatic resin ducts. X 200. Fig. 29. Transverse section through the woody axis of the cone of 6'. semperviretis. X 35. Fig. 30. Transverse section through the woody portion of the base of the cone scale of the same .species. X 50. Fig. 31. Transverse section through the upper portion of the cone scale of S. sempervirens. X 40. Fig. 32. Transverse section through the root of S. gigantea. X 4(1. Printed, November, 190°i. .04 MEMOIRS OF THE BOSTON SOCIETY OF NATURAL HISTORY VOLUME 5, NUMBER 11. FOSSIL FOOTPRINTS OF THE JURA-TRIAS OF NORTH AMERICA. By RICHARD SWANN LULL, PH. D. BOSTON : PUBLISHED BY THE SOCIETY FROM THE GURDON SALTON STALL FUND. April, 1904. APR 20 1904 11. Fossil Footprints of the Juka-Trias of North America. By Richard Swann Lull, Ph. D. (Read November 4, 1903.) "Sans duute nous devons admirer le fait qii'une crfiature si insignifiante pent laisser des traces si claires, si iiettes et si inrttlfebiles, qui existent depuis des cycles de sieoles innombrables, tandis que les efforts les plus grands de I'bomme intel- Icctuel lui peuvent survivre a peine et c|ue peu de siecles aneantis.sent son nom, son langage et ses oeuvres pour toujours." — (Winlfler, after Deanc.) Introduction. The study of ichnology has practically lain dormant since tlie death, in 18G4, of Edward Hitchcock, the founder of the science and its greatest exponent. Since that time our knowledge of early reptiles, especially the Dinosauria, has arisen and it has seemed wise to undertake anew the study of footprints in the light of modern palaeontology, with the view not only of gaining a greater insight into the natu.re and structure of the forms which frequented the ancient mud flats and beaches of Triassic days, but also of throwing light upon the correct interpretation of the remains of those evidently allied forms whose bones are known. Thus, on seeing the great collection in the Hitchcock ichnological cabi- net of Amherst college, Professor Osborn was at once struck with the possibilities of which it gave promise and suggested to the writer the line of researcli of which this dis- sertation is the first fruit. The writer has had full access, through tlie courtesy of the authorities of Amherst college and of Dr. Edward Hitchcock, Jr., in particular, to the above named collection and also to that of Mt. Holyoke college. Other lesser collections, namely, those of Rutgei-s college and of Lafayette college, which contain some of the type specimens, have been placed at the author's disposal, the only regret being that the magnificent gathering of footprints brought together by the late Professor Marsh of Yale university is as yet inac- cessible to the student. Free use has been made of Hitchcock's great works, the Ichnology of New England ('58) and the Snpplement ('65), as well as of the numerous other papers on the subject, due notice of which appears in the proper place. The drawings, with one or two exceptions, have been made l)y the author directly from nature, their final preparation for publication being the result of Mrs. Lull's skillful and painstaking endeavor. Special acknowledg- ment is due to Dr. 0. P. Hay for his valued counsel in the solution of some vexatious 462 KR'IIAKD SWAXX LULL ON problems of synonymy, but above all for his admirable Bibliography and catalogue of the fossil Vertebrata of North America (:02) which proved a great aid in the preparation of the l)ibliography. The writer is also under obligations to Prof. A. Smith Woodward, of the British museum, for a superb photograph of Chirotheriuni ti'acks, to Prof. C. H. Hitchcock for further notes on some of his species of footjirints, to Professor Emerson for notes on the geology of the Connecticut valley, and to many others wlio, by their suggestions, have aided the work. Finally, to my fi-ieiid and teacher. Professor Osborn, my gratitude is especially due for his sympathetic advice and criticism and for the great fund of knowl- edge concerning these early forms, of which he was ever ready to impart. Historical Sketch. An excellent resume of the whole progress of ichnology has been given by C. Winkler in his "Histoire de Tichnologie " ('86). but a sketch of the development of the science, especially in this country, may not be out of place. Discoceri/. — Footprints were first discovered in 1812 or 1813 in the Bunter sand- stone, at Dimifries, Scotland, but not until 1828 was the first description, that written by Duncan, o-iven to science. The famous Chirotheriuni footprints from Hildburghausen, in Saxony, were first mentioned in 1834 in a communication by Reinhard Bernhardi to the Neues iahrbuch fiir mineralogie, and were first described by J. Kaup in the same publica- tion in 1835. Another very important discovery was that of the Storeton footprint quarry near Liverpool, England, first described by Cunningham, Yates, and Edgerton in the London and Edinburgh philosophical magazine, in 1838. This locality has yielded an interest- iuo- Chirotherium of a later stage of evolution than C. harthi, and in addition there are numerous tridactyl tracks of which a study is yet to l)e made. Before the discovery of the Storeton remains, those of the Connecticut valley had t)een found, their true nature recognized, and the first notice recorded in the American journal of science and arts, in 1836. Winkler says, in speaking of the former discoveries: "' By these impressions of divers feet, the existence of reptiles and of amphibians which have left their traces in the rocks, has been proved; now it is the impressions of the feet of birds which have been found in the new red sandstone of Massachusetts." While Hitchcock was apparently the fii'st to treat the Connecticut valley impressions from a scientific point of view, yet to Dr. Deane ('44b), of Greenfield, Massachusetts, l)elongs the credit of discovery, though he believed the tracks to lie those of a turkey, and FOSSIL FOOTPl.'INTS OF TIIF JURA-TRIAS. 463 did not appreciate the full significance of the remains until Hitchcock had published his views. Collections. — Extensive collections were made, most of the specimens finding a rest- ing place in the Hitchcock ichnological cabinet which contains most of the type specimens and representatives of almost every known species. Later collections were formed at Mount Holyoke college and at Yale luiiversity. The latter collection, made under the direction of the late Professor Marsh, is said to rival that of Amherst college itself, though the specimens are as yet unavailable for study owing to lack of exhibition space. It is earnestly hoped that provisicn: for the study and display of this collection will soon be made and the results given to science. Literature. — Three monumental works on the subject of ichnology were published by President Hitchcock during his life and they form the classics of the literature of the science. The first bore the title, " An attem23t to discriminate and describe the animals that made the fossil footmarks of the United States, and especially of New England," and was published in the Memoirs of the American academy of arts and sciences, 1 848. The second work was the "Ichnology of New England,*" a large quarto, published in 1858, by the Commonwealth of Massachusetts. This was followed in 1 Sbo by the " Supple- ment to the Ichnology of New England," also published by the Commonwealth. These are in addition to numerous papers published by Hitchcock in the American journal of science and arts, and elsewhere, in all some eighteen titles. A posthumous work by Dr. James Deane entitled, " Ichnographs from the sandstone f of Connecticut river," published in Boston, in 1861, is a very interesting volume consist- ing in the main of admirably executed drawings and photographs of the tracks. The memoir itself is incomplete and adds but little to our knowledge of the subject. Classifications. — An historical review of the various classifications that have been proposed will be of interest in that they show the evolution of the subject from its incep- tion down to the year 1889, when the last impoi-tant paper was published. The first classification was proposed by E. Hitchcock ('37b) and it will be observed that the names were given to the tracks and not to the animals which made them. This classification was as follows ; — 464 RICHARD SWANN LULL ON ICHNITES. A. Tetrapodiciixites. 1 . T. didactylus. B. Sauroidichnites. 1. S. harrattii. 3. S. minitans. 2. S. 2^(^(hn HICHARD SWANN LULL ON Systematic Descriptions. Class REPTILIA. Subclass DiAPSiDA Osborn.' Superorder Diaptosauria Osborn/ Order"! PROTEBOSAUBIA Seeley. Ordinal chdruetersr Quadrupedal in gait ; nianus generally much smaller tlian the pes and five fingered though all may not always impress. Pes with four digits, generally (linosauroid in form, though plantigrade. Limbs generally long. These forms seem to represent survivoi's of the ancient stem from which the dino- saurs arose ; they may, however, represent primitive quadrupedal dinosaurs which had not yet acquired the erect gait. Family BATRACHOPODIDAE Family characters. The same as those given for the order. Digits of the pes with acuminate claws. Genus Batrachopus E. Hitchcock. (Frog foot.) Batrachopus E. Hitchcock, '45b, p. 25. Anisojms E. Hitchcock, '48, p. 226. Anisichwif! C. H. Hitchcock, '71, p. xxi, (to replace Anisopus preoccupied). Generic characters. Mauus probably with five, always with four broad clawless digits, generally directed forward. Pes four toed ; the hallux non-rotated ; all of the digits bearing slender acuminate claws; that of tlie fourth toe may be absent in the impression, possibly also in the foot; third toe the longest. Manus and pes tracks close together and nearly in a right line. Ratio of track to step, one to seven nearly. This genus was included by Hitchcock under tlie Loricoid marsupialoids from its sup- posed likeness to an armored mai'supial. Type species, B. deweyanus, E. Hitchcock. 'O.sborn. :03a. ^The charactei-s here given arc based entirely upon the tracks; for further definition of tlie orders, etc., the stiulent is directed to Zittel's Palaeontologie. FOSSIL P^WTPRINTS OF THE JURA-TRIAS. 488 of II. .038 m.; of III. the tips of the hiteral Batrachopus deweyanus E. Hitchoock. Batriichojm.s fJ(^irei/ionis E. Hitchcock. '45b. p. --J- Anisopus deweynnus E. Hitchcock, '48, p. --0 ; '58, p- fiO. pi. 9, fig. o ; pi. 41, fig. 2 ; pi. 4?., fig. 1-2 ; pi. o3. fig. 8 ; pi. 58, fig. 11. Specific characters. Pes: divarication of digits 1 and 11. 12° ; of II and III, 23° ; of HI and IV, 6° ; of I and IV. 40°. Length of digit I. .025 m. ; .043 m. ; of IV. .038 m. ; of the foot. .043 ni. Distance between toes, .028 m. Manns: divarication of digits I and 11, 53° ; of 11 ami 111, 13°; of HI and IV, 18°; of IV and V, 24° ; of I and V, 107°. Length of (Ugit I, .008 m. ; of II, .020 m. ; of III, .025 m.; of IV, .025 m.; of V, .01 '^ ni. Distance between lateral tips. .01'.) ni. Length of step, .100 to .113 m. Width of trackway, .050 to .075 m. This is a somewhat variable species, bnt in at least one specimen, no. ^f, of tlie Hitchcock cabinet, the variation is so great that it has been deemed wise to erect a new species for its reception. Type specimens: uos. ~ and ^ , of the Hitchcock cabinet on hard gray shale. Type locality not recf)rded, but the species is reported from Middletown, Connecticut. Batrachopus dispar sp. nov. Specific characters. Pes: divarication of digits I and II, 18°; of II and HI, 20°; of HI and IV, 22°; of I and IV, 60°. Length of digit I, from the middle point of the heel. .046 m. ; of II, .067 m. ; of HI, .072 m. ; of IV, .062 m. Dis- tance between lateral tips, .053 m. Length of foot, .073 m. The digits all bear slender claws except the fourth which is clawless. The toes are broad and the heel is of considerable width as the bulk of the weight was borne upon it. Length of step, .230 m. Mauus : but foui- digits impressing. Divarication of digits I and II, 26°; of II and III, 68°; of III and IV, 20°; of I and IV, 122°. Length of foot, .030 m. Distance between tips of the lateral toes, .028 m. The manus of this form is about equal in size to that of B. deweyanus, while the pes is twice as large. The name dispar is given on account of the great disparity in size of the fore and iiind feet (fig. 2). The type is no. ~, of the Hitchcock cabinet, on red shale from the Lily pond at Turner's Falls, Massachusetts. yiv.. 2. JJatraclwpiat dis- par Lull. Impressions of the left manus and pes. X i- ]Jrawn from the type specimen, no. -j'l '" the Hitchcock cabinet. 484 RICHARD SWANN LFLL ON Batrachopus gracilis (K, Tliiclionck). Anisopus gracilis E. Hitchcock, '48, p. 22S, pi. I(i, fig. .3-4; '58, p. fil. pi. 0, fig. 4; pi. 35, fig. 5; pi. 36, fig. 1-5; pi. 58, fig. 9. Anisichnus gracilis C. H. Hitchcock, '89b. p. 119. Specific characters. Pes : divarication of digits I and H, 23° ; of II and III, 20°; of III and IV, 30° ; of I and IV, 73°. Length of digit I, .011 m.; of II, .021 m.; of III, .023 m.; of IV, .031 m. Length of foot, .036 m. Distance between lateral tips, .028 m. All of the digits are clawed. The variation of the figured specimen, no. ,-^, from Hitchcock's described type is mainly in the divarication, never a con- stant factor. Manns: divarication of digits 1 and 11, 23°; of II and 111, 25°; of 111 and IV, 44°; of IV and V, 62°. Length of digit 11, .012 m.; of 111, .013 m.; of IV, .011 m.; of V, .004 m. The poUex rarely impresses and often the fifth digit is obscure gi\dng practically a functionallv tridactyl track. There seems to l)e a wide range of variation in divaii- cation in the manus as well. Length of step, .209 m. Manns placed just in advance of the pes. This form is smaller than either of the preceding species (fig. 3) . The type specimen is no. ^, of the Hitchcock cabinet, on a slab of dark shale whose locality is unrecorded. The species is reported from Massachusetts, Connecticut, New Jersey, and Pennsylvania. Batrachopus gracilior (E. Hitchcock). Anisojms graclHor E. Hitchcock, '63a, p- 54 ; '65, p. 6, pi. 1, fig. 3. Anisichmis gracilior C. H. Hitchcock, '89b, p. 119. Specific characters. Pes: divarication of digits 1 and II, 14'; of II and 111, ir; of 111 and IV, 15.5°. Length of digit I, to center of heel, .909 m.; of II, .0125 m.; of 111, .014 m.; of IV, .015 m. Length of foot, .015 m. Distance between lateral tips, .012 m. Manus: divarication of digits 1 and II, 35°; of II and III, 37°; of III and IV, 11°; of IV and V, 77°. Length of digit I, from center of the rear of the track, .005 m.; of II, .008 m.; of III, .008 m.; of IV, .007 m.; of V^ .005 m. Length of foot, .008 m. Length of step, .94(3 m. Width of trackway, .05 m. Ratio of foot to stride, as one to three. Fig. 3. Batrnrhopns gracilis E. Hitchcock. Successive tracks of right and left manus and pes, showing the relative length of step to foot impression, x J. From the type spec- imen, no. •'/, of the Hitchcock cabinet. FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 485 This form is distingviisliecl from B. gracilis by its smaller size aud much shorter hmbs and wider body, in fact it seems somewhat doubtful whether the species should properly be referred to this genus ; it surely is not a typical Batrachopus. Type specimen, no. ^, of the Hitchcock cabinet, on reddish shale ; locality imrecorded. Batrachopus bellus (E. Hitclicock). Apatichnus hellus E. Hitchcock, '58, p. l"l, pi. 17, fig. 6; pi. .35, fig. 8; pi. 45, fig. 6. Sjieclfic characters. Pes: divarication of digits II and III, 30°; of III and IV, 30°, Length of digit I, .005 m.; of II, .010 to .018 m.; of III, .020 to .025 m.; of lY, .015 to .020 m. Length of foot, .026 m. Manus: divarication of outer toes, 40°. Length of foot, .013 m. Length of step, .100 to .170 m. Width of trackway, .063 m. Ratio of foot to step, about one to six on the average. This form is long of limb and strictly quadrupedal in gait thougli the light impression of the manus is not always discernible. The latter character removes it from Apatichnus and both characters would tend to ally it with Batrachopus. In size it lies between B. gracilis and B. gracilior but the length of limb would place it nearer the former. The type is no. H, of the Hitchcock cabinet, on red shale, from Turner's Falls, Massachusetts. Genus Cheirotheroides E. Hitchcock. (Chirotherium-like.) Cheir Other aides E. Hitchcock, '58, p. 130, pi. 23, fig. 4; pi. 36, fig. 6; pi. 54, fig. 3. Generic characters. Quadrupedal in gait; feet unequal in size, pes functionally tet- radactyl, manus pentadactvl. The three inner digits of the pes generally terminate in pellets, the fourth digit does not. The presence of a fifth digit to the pes is apparently indicated in some specimens, but rarely impresses itself. The limbs are rather short, the ratio of foot to step being as three to four, though the length of step varies. Cheirotheroides pilulatus E. Hitchcock. • Cheirotheroides pilidatus E. Hitchcock, '58, p. 130, pi. 23, fig. 4 ; pi. 36, fig. 6 ; pi. 54, fig. 3. Specific characters. Pes : divarication of digits I and II, 10°; of II and III, 15°; of III and IV, 15°. Length of digit I, .010 m.; of II, .014 m.; of III, .018 m.; of IV, .018 m. Length of foot, .225 m. Distance between lateral tips, .014 m. 486 RICHARD SWANN LULL ON Manus: divarication of digits I and II, 57°; of II and III, 6U°; of III and lY, 28°; of IV and V, 20^ Length of digit I, .004 m.; of II, .008 ui.; of III, .009 m.; of IV, .006 in.; of ^^ .004 m. Length of step, .320 m. Width of trackway, .570 m. This species resembles Batrachopas gracilior most closely, especially in the short limbs and broad body, but differs therefrom in the pelletrlike character of the claws. It may be that the last character is of specific value only and that the two forms mentioned should be brought together under one genus. The present species is extremely rare and is in need of further study before its true character can be learned. It seems best to place it under the Proterosauria because of its pentadactyl inanus which Gadow claims is never found among the Amphibia. However, it seems quite far removed from the typical Batrachopus. Type specimen, no. M, of the Hitchcock cabinet, from Turner's Falls, Massachusetts. This is specimen no. l^ of the Ichnology. Superorder Dinosauria Owen. Ordinal characters. ' Bipedal in gait. Pes ornithoid, structurally tri- or tetradactyl, though generally functionally tridactyl. Manus never impressing (Megalosauria) , or occasionally resting upon the ground (Orthopoda), but never used for locomotion. Manus pentadactyl. Caudal trace sometimes present. Order THEROPODA Marsh. Strictly bipedal, digitigrade forms, with a tetradactyl mesaxonic foot, functional, subfunctional, or vestigial hallux. Claws acuminate but not strongly recurved in Triassic forms. Lunbs moderately long and trackway narrow. Occasional tail trace. Family ANCHISAURIPODIDAE. Footprints of dinosaurs of the family Anchisauridae. Family characters. Bipedal, tetradactylous; hallux, when impressing, rotated to rear, insistent. Well marked phalangeal pads; anterior claws acuminate, but not strongly raptorial. No manus nor caudal impressions. But one genus: Anchisauripus. Genus Anchisauripus gen. nov. (Foot of Anchi,sanru8.) Mibrontes E. Hitchcock, '45b. p. 23 (in part) . Brontozovm E. Hitchcock, '47, p. 50 (in part) . ' Definition applying to Connecticut valley dinosaurs. FOSSIL FOOTPRINTS OF THE .TITRA-TRIAS. 48/ Generic characters. Bipedal,' tetradactylous ; hallux rotated to the rear so as to lie in line with the claw ol' the second digit, insistent, that is, inserted high on the leg so that only tile tip of the claw impresses and that only when the weight is borne on the hinder part of the foot. The hallux evidently bore a well developed, subfunctional, grasping claw. Foot of moderate size with well marked phalangeal pads. Limbs of medium length. Manus and tail never impressing. This genus is clearly correlated with the Anchisaurus and Ammosaurus of Marsh and is here separated from Hitchcock's genus Eubrontes (Brontozoum) the latter being retained for the larger herbivorous forms which were grouped with the carnivorous species. The type species is Anchisaurijins dananus (Brontozouni sinimanium, in part, of the Ichnology) the track of Anchisaurus column Marsh. Anchisauripus dananus (E. Hitchcock). Eubrontes dananus E. Hitchcock, '45b. p. 2o (in part). Brontozoum sillimanium E. Hitchcock, '47, p. 49 ; '58, p. 68, pi. 12, fig. 3 ; pi. 33, fig. 4-5 ; pi. 43, fig. 6, (in part) . Specific characters. Divarication of digits I and H, 139° ; of H and HI, 11°; of HI and IV, 18°. Length of digit I, .050 m. ; of 11, .077 m.; of HI, .115 m.; of IV, .088 m. Length of foot, not including the hallux, .153 m. ; with the hallux. .187 ni. Distance between lateral tips, .067 m. Length of step, from .300 to .560 m. Width of trackway, .115 m. The type specimen is no. ^, of the Hitchcock cabinet ; reddish flagging stone fi'om Middletown, Connecticut. Figured in F. A. Lucas, :01, figure 7. This 18 undoubtedly the track of Anchisaurus colurus Marsh ('96, p. 148, pi. 2, fig. 1-3 ; pi. 3, fig. 1-2) from the exact way in which the bones fit the track (fig. 4) . This is an extremely common and variable species, the variations consisting in size, complexity of heel pads, breadth and divarication of toes, and the shape of the claws. E. Hitchcock ('58, p. 69) in speaking of this form says: "I have foiuid it chfficult to define the limits of tliis species and I apprehend that as now given it embraces at least two species. But I have failed to seize upon any distinctive characters between them." It seems to 1 /. Fig. 4. Anchisauripus daiiaiius E. Hitchcock. Impre&s of the left pe.s. X 2- From the type, no. J",-, of the Hitchcock cabinet. The skele- ton is based upon that of Anchisan- rus colurus Mar.sh. 488 RICHARD SWAXN LULL ON the present author that a di\dsion can be made upon the ground of size, though whether this would agree with what Hitchcock had in mind one cannot say. There are, however, certain specimens whose size agrees with what one would expect the pes of Anchisaurus {Megadactylus) polyzdus E. Hitchcock, Jr., to be, judging from the relative sizes of the known part of the skeleton and that of A. colurus, and it is pro- posed to place these specimens under a new species bearing the name of Anchisauripus hitchcocki in honor of the great ichnologist. Anchisauripus hitchcocki s)>. nov. Synonymy as in A. dananus. Specific characters. Divarication of digits I and H, 138°; of n and HI, 19°; of III and IV, 14°; of II and IV, 33°. Length of digit II, .060 m.; of III, .088 m.; of IV, 1/ Fig. .5. Anchisauripus hitch- cocki Lull. Impression of the right pes. X 5. From the type .075 m.; of the foot, CXclusive of specimen, no. ^A, of the Hitch- hallux, .119 m.; including the hal- lux, .140 m. Distance between lateral tips, .067 m. (see fig. 5) . The type specimen is an individual track, no. ^, of the Hitchcock cabinet, associated with A. minusculus and is figured by E. Hitchcock ('65, pi. 16, fig. 1). Ou shale, from the Lily pond, at Turner's Falls, Massachusetts. This species is correlated with Anchisaurus {3Iega- dactylus) polyzelus E. Hitchcock, Jr., the first dinosaur found in the valley, the type of which is preserved in the Hitchcock ichnoloo-ical cabinet at Amherst. Anchisauripus tuberosus (E. Hitchcock). Eubrontes tuherosns E. Hitchcock, '45b, p. 23. '• / ..• Brontozourn Joxonyx E. Hitchcock, '48, p. 172, pi. 2, ^. ' ' >- i 7 Fig. 6. Anchisauripus tuberosus E. ^S- 1~-J- Hitchcock. Track of the right pes. XL Brontozourn validuin E. Hitchcock, '58, p. 07, pi. 12, ^'k™ "le type, no. fj, of the Hitchcock tig. 2 ; pi. 38-51 ; pi. 57, fig. 3. • ~ cabinet. The hallux impression is re- stored from another specimen. Specific characters. Divarication of digits I and 11, ? 135° ; of II and III, 14° ; of III and IV, 13°. Length of digit I, about? .055 m. ; of II, .086 m. ; of III, .128 m.; of IV, FOSSIL FOOTPRINTS OF THE JFRA-TRIAS. 489 Tin 111. Length of foot exclusive of hallux, .168 m. ; with the hallux,? .195 m. Length of step, .440 ni. Other specimens than the type show measurements somewhat in excess of those given above. This is a very numerous and variable type, in .size between Aurhisaiirijjus danumis and A. exsertii.'i, with no marked peculiarities other than size to distinguish it from either. The type specimen, no. f^, of the Hitchcock cabinet, a superb track, has unfortunately been trimmed in such a way as to destro}' the impression of the first claw, but the Imsal pad of the hallux is clearly impressed. It is figured in the Ichnology on plate 57. figure 8. Specimen no. ^, while somewhat larger, gives all of the characters, including the hallux. Type, no. ||, of the Hitchcock cabinet, on red shale from Turner's Falls, Massachusetts (fig. 6) . Anchisauripus exsertus (K. Ilitchcotk). Bronfozoiim exaertidn E. Hitchcock, '58, p. 07, pi. l-l, fig. 1 ; pi. 40, fig. .3. Specific characters. Based on no. ^. Divari- cation of digits I and II, 75° ; of II and III, 20° ; of III and IV, 20°. Length of digit I, .075 m. ; of II, .117 m. ; of III, .161 m.; of IV, .15.S m. Length of foot, exclusive of hallux, .226 in. ; including the hallux, .265 m. Length of step in uo. ^ (a somewhat larger specimen), .922 m. The real distinction between this species and A. tuherosus seems to be one of size only, for the character which gives the name " exsertus,'" that of the unusual projection of the middle toe Fi-. 7. Anchisauripus exsertus E. Hitdifiock. beyond the lateral ones, is not always manifest. luipiint of tiie left pes. x k. From no. ii. of the This species is correlated with A)n»iosai(n(s inajor Marsh ('96. p. 147, pi. o, fig. .3-6). Type specimen, no. ^, of the Hitchcock cabinet, on gray micaceous sandstone from Smith's Ferry, Massachusetts (fig. 7, of no. — ) . Hitclifock cabinet. The bone re.storation is after that by Marsh of Amniosaurns major Marsli. 490 RICHARD SWANN LUIJ, OX Fig. 8. Anchisauripus minusculus (E. Hitchcock). Track of the right pes with a restoration of the bones of the foot. X '.. Driiw ii from tlie type, no, J '■. in the Hitchcock 'cabinet. Anchisauripus minusculus (E. Hitchcock). lirohfozouiii mi7H(sct(- luin ¥j. Hitclicot'k, '58, p. 6-3, pi. 11, tig. 1; pi. 40, fig. 2; pi. 41, fig. 1; pi. 42, fig. 3; pi. 57, fig. 2. Specific cluti'dcteis. Di- varication of digits 1 and II, 140°; of II and III, 24°; of III and IV, 24.5°. Length of digit I, .100 m.; ofll. .15.S m.; of III, .192 m.; of IV, .223 m. Length of foot, ex- clusive of the hallux, .307 m.; including the hallux, .374 ni. Length of step, 1.000 m. This magnificent form is the largest of the genus and indicates an animal about twice the size of Anchisauriis colurus, which would give it a length of about fourteen feet. The type specimen, the one here figured (fig. 8), is no. ^, from the Hitchcock cabinet, on fine red shale from the Lily pond at Tur- ner's Falls, Massachusetts. Anchisauripus parallelus (E. Hitchcock). GraUator paraUelns E. Hitchcock, '65, p- 7, pi. 5, fig. \. FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 491 Specific characters. Divarication of digits I and II, 141°; of II and III, 12°; of III and IV, 6.5°. Length of digit I, .067 m. ; of II, .079 ni. ; of III, .120 m.; of IV, exclu- sive of "heel" pad, .090 m. Length of foot exclusive of the hallux, .IGo m. ; including the hallux, .210 m. Length of step, .260 ni. This form is evidently not a (rrallator from the shortness of step and the wide track- way. The presence of the hallux removes it from Grallator and associates it with Anchisauripus, though the presence of the three heel pads separates it from .1. (hmanus, its nearest ally in point of size. It is also peculiar in the , ^^^ slight divarication of the toes, hence the specific name (fig. 9) . Type, no. '^^, of the Hitchcock cabinet, on red sandstone from Gill, Massachusetts ; also reported from New Jersey. Anchisauripus tuberatus (E. Hitchcock). Bioiitozoinii tiiberatuni E. Hitchcock, '58, p. 66, pi. 1 1, fig. 2; pi. 52, fig. 7. ///, r\ • \ Specific characters. Divarica- tion of digits I and II, not known ; o f n and 111. 17°; of III and IV, 8°. Length o f digit II,. 140 m.; of III, .172 m.; of IV, .107 m. Length of the foot, exclusive of hallux. .249 m. Distance between lateral tips. .152 m. This species resembles A. exsertus in size, being but little larger, but the two forms are readily distinguished by , , , , , , , the broad tuberous i^halanges of the one Fig. 10. Aiichisaunpustuoeratus {h. Hili^hcocK). Impress or the ■■ ^ right pes, X \. From the type, no. f J, in the Hitchcock cabinet. in ((UestioU. lu general character, the /. Fig. 9. Anchisauripus parallelux (E. Hitchcock). Impression of the left pes. X J. From the type, no. V-, of tlie Hitchcock cabinet. 492 RICHARD SWANN LULL ON foot is amu'ctaiit Ijetweeii Anchisauripus ami Euliroiiti'.s. tlie acumiuate claws aud small size alone among the known characters affiliating it witli the former. Unfortunately, the type specimen, no. ", has been so trinuued as to destroy the hallux impression if it were present so that the presence or absence of this characteristic mark cannot be ascertained (fig. 10). 'i'he type, no. -j, of the Hitchcock cabinet, is on red shale from Turner's Falls, Mass'a- chusetts. Family GIGANDIPODIDAE. FaiiiUi/ rhararters. Large bipedal forms. Tetradactyl, hallux half rotated, incum- bent. Foot flatly digitigrade. Claws acuminate. No manus impres.sion. Caudal trace sinuous and continuous. Genera: Gigaudipus, possil)ly also Hyphepus. Genus Gigandipus K. Ilitchfock. (Giant foot.) Gifjad'ipKs Vj. Hitchcock, 55, p. 417 (no description) . Gigandipu.'i E. Hitchcock, '56, p. 'J7. Giyantitherium E. Hitchcock, '58, p. '-'o. Generic rliuraeters. Bipedal, tetradactyl, hallux incumbent, that is, inserted low on the leg so that its whole length is on the ground ; rotated at right angles to the second toe. Hallux but feebly developed. Foot with distal ends of metatarsals upon the ground in contrast to Anchisauripus in which the foot rests upon the toes only. Claws acumi- nate; that of digit 11 especially strongly developed. Tracks nearly in a right line. Caudal trace sinuous and continuous. The foot of this form agrees very closely in structure with that of AUosaurus (Osborn. :00, p- T<. Divarication of digits II and III, 22° to 23°; of HI and IV, 14° Fig. 15. Grallator cuaentiis E. Hitchcock. Impression of the left pe.s. X |. From ni>. J,?, of the Hitchcock cabinet. FOSSIL FOOTPRINTS OF THE .TT^RA-TRIAS. 497 to 1(3 ; of II and IV , 35° to 40°. Length of digit II, .026 m.; of III, .035 in. ; of IV, .030 in. Distance between later- al tips, .027 in. Length of foot. .045 m. Pro- jection of middle toe he_yond tlie lateral ones, .017 in. Length of step, .315 m. Charles Hitchcock's character of the non-ex- tension of the inner toe so far as the outer one seems to be inconstant for they are about equal in extent in the present author's figure, from no. \^ (Hitchcock cabi- net). This, one of the most diminutive of dino- saur tracks, represents a foot about two thirds the length of that of Comp- sognathus of the lower Kimeridgiau limestone of Bavaria, the smallest known form. The type is no. ~, of the Hitchcock cabi- net, on red shale from Turner's Falls, Massa- chusetts, and the figured specimen is no. ^ from the same locality (fig. 17) . The species is reported from Massachusetts and New Jersey. Via. 11). Grallatur formosus E. Hitclicock. Imprint of tlu- lell pes. the type specimen, no. f, of the Hitclicuck cabinet. From 498 IIICHARD SWANX LULL ON This is one of the " leptodactylous " genera whose characters it is very chfficult to make out. It would seem best to place it provisionally with the carmvorous dinosaurs because of the bipedal gait aud dinosauroid character of the toot. ■516 RICHARD SWANN LULL ON Platypterna deaniana E. Hitchcock. Platypterna deauuinuti E. Hitclicuck. '45b. p. 25; '58, p. So, pi. 14, fiu-. 4. Specific characters. Pes: divarication of digits II and III, 40° to 4-3°; of III and IV. 25° to 30°; of II and IV, 60° to 70°. Length of digit II, .038 in.; of III, .07(3 m.; of IV, .051 m. Heel: length, .030 m.; breadth. .023 ni. Distance between lateral tips, .0-31 to .063 m. Length of foot, .100 to .115 ni. E. Hitchcock ('65, p. 2) speaks of this form as of doubtful validity, possibly because of its probable identity with SlUhuanius tetradactylus. The type specimen is no. % of the Hitchcock cabinet, on fine red shale from Weathersfield, Connecticut. Platypterna concamerata (E. Hitchcock). Harpedactylus concmneratus E. Hitchcock, '48, p. 207, pi. 14, fio-. 3. Platypterna varica E. Hitchcock, '58, p. 85, pi. 14, fig. 8 ; pi. 47, fig. 4. Sjjecfic characters. Pes: divarication of digits II and HI, 23°; of TIT and IV, 52°; of II and IV, 75°. Length of digit II, measured from the middle of the heel, .076 m.; of HI, .01)1 m.; of IV, .051 m.; of the heel, .028 m. Width of heel, .050 m. Length of foot, .127 m. Distance between lateral tips, .094 m. Length of step, .200 to .300 m. Width of trackway, .280 m. This form is peculiar in the size and breadth of the heel and the cur\'ature of the toes. It is also remarkable for the extreme width of the trackway as the specific name impUes. The type specimen is no. ^, of the Hitchcock cabinet, on graj- micaceous sandstone from Turner's Falls, Massachusetts. Platypterna digitigrada E. Hitclieock. Platypterna digitigrada E. Hitchcock, '58, p. 86, pi. 14, fig. 9; pi. 51, fig. 2. Specific characters. Pes: divarication of digits II and III, 43°; of HI and IV, 37°; of II and IV, 80°. Length of digit II, .020 m.; of III, .030 m.; of IV, .023 m. Distance between lateral tips, .040 m. Length of foot, .050 m.; width of heel, .020 m. Length of step, .100 to .115 m. Width of trackway, .076 m. Toes curving inwards; thick, with acuminate claws. This track is analogous to that of Platyj^tenia gracillinia. that is, a further caving of FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 517 the mud in the present instance would readily produce the latter, though no real clue to its identity with any other genus is shown. The type specimen is no. f|, of the Hitchcock cabinet, on shale from Turner's Falls, Massachusetts. ? Platypterna gracillima E. Hitchcock. Platiipterna gracillima E. Hitchcock, '58, p. 86, pi. 14, fig. 12. Specific characters. Pes: divarication of digits II and III, 20°; of III and IV, 50°; of II and IV, 70°. Length of digit II, .025 m.; of III, .038 ra.; of IV, .032 m. Distance between lateral tips, .036 m. Length of step, .127 to .140 m. Width of trackway, .076 m. Foot digitigrade, outer toes curved inward. This track is like that of a miniature of Argoides redfieldianm, which is probably to be identified with Euhrontes dwaricatus. The foot approximates most nearly that of Grallator gracilis; but the angles of divarication are far greater in the present form. The species is evidently not of the genus Platypterna but is left therein provisionally until further light is had upon its affinities. The type is no. ^, of the Hitchcock cabinet, from Turner's Falls, Massachusetts. Platypterna tenuis E. Hitchcock. Platypterna tenuis E. Hitchcock '45b, p. 25; '58, p. 84, pi. 14, fig. 5; pi. 58, fig. 10. Specific characters. Pes : divarication of digits II and HI, 20° to 30° ; of III and I V^ 25° to 30° ; of II and IV, 45° to 00°. Length of digit II, .025 m.; of III, .042 m.; of IV, .035 m. Breadth of heel, .015 m. Distance between lateral tips, .048 m. Length of foot, .069 m. Length of step, .178 m. Width of trackway, .050 m. The form is semiplantigrade so that the whole foot does not impress ; a long Umbed, delicate type. The type specimen is no. };, of the Hitchcock cabinet, on red shale from Weathers- field, Connecticut. Platypterna delicatula (E. Hitchcock). Calopm delicatidus E. Hitchcock, '45b, p. 25. Pkdypterna delicatida E. Hitchcock, '58, p. 84, pi. 14, fig. 6 ; pi. 58, fig. 8. Specific characters. Pes: divarication of digits II and III, 22°; of HI and IV, 18°; of II and IV, 40°. Length of digit II, .017 m.; of HI, .028 m.; of IV, .010 m.; of the heel, .010 m. Widtli of heel, .008 m. Distance between lateral tips, .015 m. Length of step, .076 m. Width of trackway, .050 m. 518 RICHARD SWANN LULL ON This is the smallest representative of the genus. Type specimen, no. {-\, in the Hitchcock cabinet, on red shale from Weathersfield, Connecticut. Platypterna recta (E. Hitchcock). Hdvpedactylus rectus E. Hitchcock, '48. p. 209, pi. 5, fig. 5 ; pi. 24, fig. 7. Phdiipterna recta E. Hitchcock, '58, p. 84, pi. 14, fig. 7; pi. 47, fig. 3. Sjjeclfic characters. Pes: divarication of digits II and HI, 10° ; of HI and IV, 27°; of 11 and IV, 36°. Length of digit II, .055 m.; of HI, .080 m.; of IV, .060 m. Distance between the lateral tips, .063 m. Length of track, .095 m. Width of heel, .045 m. Length of step, .140 m. Width of trackway, .140 m. In this form, as in I\ tenuis, the foot is semiplantigrade so that the entire foot does not impress. The toes are straight but the short step and wide trackway indicate a very short limbed, wide bodied form as in the case of P. concamerata. The type is no. I, of the Hitchcock cabinet, on hard argillaceous sandstone, from Gill, Massachusetts. Genus Argoides E. Hitchcock. (Cyclops-like.) Argoides E. Hitchcock, '45b, p. 24. Arrjcjzoum E. Hitchcock, '58, p. 81. Generic characters. Bipedal, leptodactylous, tridactylous: Toes curved, the latter ones more or less outward and upward behind, so as to be keel shaped. Digitigrade, rarely showing a heel. Argoides isodactyletus (E. Hitchcock). Argoides isodactyletus E. Hitchcock, '45b, p. 24. Argoides minimus E. Hitchcock, '45b, p. 24. Argozoum 2'>(i'>'idigitatum E. Hitchcock, '58, p. 82, pi. 14, fig. 3-; pi. 35, fig. 4; pi. 39, fig. 1. Plesiornls aequcdipes E. Hitchcock, '58, p. 104. Sjyecific characters. Pes: divarication of digits 11 and HI, 40° to 50°; of III and IV, 40° to 50°; of II and IV, 80° to 100°. Length of digit II, .023 m.; of HI, .033 m.; of IV, .025 in. Distance between tlie lateral tips, .027 m. Length of foot, .030 m.; of the step, .1 52 m. Width of trackway, .043 m. The size coupled with the extreme length of liml) in this form, strongly suggests the FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 519 genus Grallator. but the other characters are so obscure that it is difficult to assure one's self of their identity. Tj-pe, no. ^, of the Hitchcock cabinet, ou red shale, with shrinkage cracks, from the Lily pond at Turner's Falls, Massachusetts. Argoides macrodactylotus (E. Hitchcock) . Platijpterna macrodactylotus E. Hitchcock, •45b, p. 25. Argozoum disparidigitatum E. Hitchcock, '58, P- 82, pi. 14, fig. 2. Specific characters. Pes: divarication of digits II and III, 18° to 30°; of III and IV, 20° to 25°; of II and IV, 40° to 55°. Length of digit II, .076 m.; of III, .127 m.; of IV, .01)0 ni. Length of foot, .140 m. Distance between lateral tips, .076 m. Length of step, 380 m. Width of trackway, .100 ni. Type, no. f^-, of the Hitchcock cabinet, from Weathersfield, Connecticut. Argoides redfieldianus E. Hitchcock. Argoides redjieldianas E. Hitchcock, '45b, p. 24. Argozouvi redfieldlanum E. Hitchcock, '58, p- 81, pi. 14, fig. 1. This track agrees in length and divarication of digits with that of Eubrordes dimricatus and is undoubtedly synonymous with that species. The analysis of coproUtes found associated with these tracks betrays the presence of uric acid which would place the form unquestionably among the Sauropsida but not necessarily with the birds (E. Hitchcock, '58, p. 43) . Argoides robustus E. Hitchcock. Argoides robustus E. Hitchcock, '45b, p- 24. Tliis form is not mentioned in any subsequent work^ and should therefore be dropped from the list. What disposition was made of the specimens cannot be determined. Genus Tarsoplectrus nom. no v. (Spurred tarsus.) Plectropus E. Hitchcock, '45b, p. 24 (in part) . Flectropterna ^. Hitchcock, '58, p. 108 (in part) for Plectropus, preoccupied. Generic characters. Bipedal, tetradactyl, plantigrade, heel narrow, tapering back- ward, not always wholly hnpressing. Limbs long; trackway narrow. No phalangeal pads nor distinct claws. 520 RICHARD SWANN LULL ON This genus as at present restricted coiitiiiiis hut two species, T. (iiKjufttus (E. Hitch- cock) and 1\ eh(j(ins (C.H.Hitchcock). The uame Plectropterna unfortunately cannot be retained, as the type species, P. minitans, pro\es to he synonymous with Anonibejms intennediuH, the oUI generic name becoming thus a synonym for Anonioepus. The type species is Tdrsoiih'cfnix aur/iisfus. Tarsoplectrus angustus (K. Ilitcluock). Plectroptenia (i/Kjusfa E. Hitchcock, '58. p. 11", pi- 1«S, hg. 4 ; pi. 30, tig. 3. Specific characters. Pes: divarication of digits 1 and 11, !)5° ; of H and 111, 22°; of HI and IV, 25°; of 11 and IV, 47°. Length of digit 1, .018 m.; of II, .051 m.; of 111, .071 m.; of IV, .046 m. Distance hetween lateral tips, .04(1 m. Length of foot, .110 m. Length of step, .305 m. Widtli of trackway, .068 m. Toes slightly curved. Hallux strongly recurved arising about the middle of the length of the heel. Type specimen, no. ||, of the Hitchcock caljinet, from Turner's Falls, Massachusetts. Tarsoplectrus elegans (C. H. Hitchcock). Plectropterna elegans C. H. Hitchcock, '89b, pp. 122, 125. Specific characters. Pes : divarication of digits II and 111, 30° ; of III and IV, 40° ; of II and IV, 70°. Length of digit I, .023 m.; of II, .026 to .045 m.; of HI, .051 to .076 in.; of IV, .038 to .045 ui. Length of foot, .127 to .132 m. Distance between lateral tips, .050 to .000 ni. Length of step, .457 to .533 m. Width of trackway, .077 m. Type specimens, nos. 53, Ul, and 242, in the Mt. Holyoke cabinet, from Weathers- field, Connecticut. Genus Polemarchus E. Hitchcock. (A leader in war.) Polemarchtis E. Hitchcock, '45b, p. 24 ; '58, p. 107, pi. 18, fig. 1; pi. 5'.', fig. 3. freneric characters. Bipedal, tetradactyl, plantigrade, with broad heel and with a large, half rotated hallux. Toes slender in the track, but the latter, which is of shale, has doubtless caved in to some extent. No pads nor claws in evidence. Except for the presence of the hallux this form most nearly approximates Platyp- terua. There is hut one extremely rare species: Polemarrhns giyas. Polemarchus gigas E. Hitchcock. Polemarclms gigas E. Hitchcock, '45b, p. 24; '58. p. 107. ])1. IS, fig. 1 ; pi. 59, fig. 3. Specific characters. Pes: divarication of digits 1 and 11, 61"; of 11 and HI. 20°; of FOSSIL FOOTPRINTS OF THE ,TURA-TRIAS. 521 III and IV, 25°; of II ami IV, 45°. Length of digit I, .004 m.; of II. .217 m.; of III, .285 m.; of IV, .213 m.; of the heel, .OUT m. Length of foot, .370 m. Width of the heel, ,100 m. Distance between tips of the lateral toes, .105 to .222 ni. Length of step, 1.224 m. Width of trackway, ? .350 ni. The hallux is straight, the other digits curve inward. The type specimens are nos. f|, f|, and ^, of the Hitchcock cabinet, in slightly cal- careous shale, the first two from the middle of the Connecticut river at Chicopee Falls, Massachusetts, the last from near Cabotville, Massachusetts. Genus Plesiornis E. Hitchcock. (Near a hird.) Pleswrnis E. Hitchcock, '58, p. 102. Generic characters as given l^y Hitchcock : '' tridact^'lous, pachydactylous, hind foot slightly the largest. Toes shghtly turned in towards the line of direction; terminated by blunt claws, or pellets. Highly ornithoid; the tracks distinguished from those of birds only by being arranged two ))y two along the median line, with a wide interval between." The footprints thus described by Hitchcock under this genus are doubtless in every instance those of two animals walking oue after the other, a tlieorv which Hitchcock at first held, but afterwards abandoned on the ground that such tracks occurred too fre- quently to be thus explained. The so called fore foot track is a typical pes impression and never that of such a manus as one would expect from the very Anomoepus-like appearance of the hind foot. That one animal followed another frequently is not unlikely, if, as the present author believes, the animals resorted to the congregating places for breeding purposes, and the slight difference in size could readily be a sexual character. The quadrupedal nature of the tracks seems amply disproved. Some of the species are referable to known bipedal forms, the others it will be necessary to retain under the present genus, whose revised characters may be thus defined : bipedal, digiti- grade, tridactyl forms, digits terminated by bhuit or pellet-like claws. Small forms of doubtful affinity. Plesiornis pilulatus E. Hitchcock. Plesiornis jMidatus E. Hitchcock, '58, p. 103, pi. 17, fig. 8; pi. 30, fig. 4. Specific characters. Pes: divarication of digits II and 111,35°; of HI and IV, 35°; of II and IV, 70°. Length of digit II, .033 m.; of HI, .053 m.; of IV, .038 m. Length of foot, .053 m. Distance between lateral tips, .038 m. Length of step, .183 m. Width of trackway, .050 m. The foot is quite similar to that of Grallator, except for the form of the claw and the occasional presence of a spur-like process on the iinier side of the foot. 522 HrCHARD SWAXX LULL OX Type, no. ^, of the Hitchcock cabinet, on gniy sandstone from Turner's Falls, Massa- chusetts. Plesiornis mirabilis E. Hitchcock. Plesiornis mirabilis E. Hitchcock, '65. \). 35, pi. 20. Possibly referable to Anchisauripus tuberosus E. Hitchcock, especiall}^ the larger track, though the smaller track does not resemble it very closely. This species is based upon a single specimen, no. f^, of the Hitchcock cabinet, which is peculiar not only in the lack of similarity of the two sets of footprints, but also in the presence of more or less parallel markings which may be due to dragging tails or limbs or to some other body which may have been drawn along. Plesiornis giganteus C. H. Hitchcock. Plesiornis giganteus C. H. Hitchcock, '89b, pp. 118, 122, 126. Probably referable to Anchisauripus minusculus. Genus Sillimanius E. Hitchcock. (For B. Silliman.) Sillimanius E. Hitchcock, '45b, p. 24. Ornithopus E. Hitchcock, '48, p. 191. Generic characters. Bipedal, tetradactylous, hallux rotated so as to be in line with the fourth digit. Digitigrade to semiplantigrade. This genus is founded on Weathersfield shale specimens and the true characters are obscured. The type species is Sillimanius tetradacti/lus E. Hitchcock. Sillimanius tetradactylus E. Hitchcock. Sillimanius tetradactylus E. Hitchcock, '45b, p. 24. Ornithopus gallinaceus E. Hitchcock, '48, p. 192, pi. 8, fig. 1; '58, p. 87, pi. 14, fig. 10; pi. 58, fig. 1. Sjjccific c/iaracters. Pes: divarication of digits I and II, 110° ; of 11 and III, 35°; of III and IV, 45°; of II and IV, 80°. Length of digit I, .043 m.; of II, .043 m.; of III, .076 m.; of IV, .051 m. Length of foot impression, .097 m. Distance between lateral tips, .069 m. Length of step, .178 m. Width of trackway, .064 m. Foot semiplantigrade. Type, no, ||, of the Hitchcock cabinet, on red shale, from Weathersfield, Connecticut. FOSSIL FOOTPRINTS OF THE .riTRA-TRTAS. 523 Sillimanius gracilior E. Hitchcock. Sillimaidus gracilior Vj. Hitchcock, '45b, p. 24. Ornithojjvs r/rnr!Jlor E. Hitchcock. '48, p. 193, pi. 8, fig. 2 ; '58. p. H8. pi. 14, fig. 11 ; pi. 58, fig. 7. Specific characters. Pes: divarication of digits I and II, S5° ; of II and III, 35°; of 111 and IV, 52°. Length of digit I, .010 ni. (impression) ; of II, .021 ni.; of III, .032 ni.; of IV, .023 \\\. Distance between lateral tips, .043 m. Length of foot impression, .043 m. Length of step, .153 m. Width of trackway, .115 ni. Foot digitigrade, entire length of the hallux not impressing. The type specimen is no. •^, of the Hitchcock cabinet, on red shale from Weathers- field, Connecticut. Oenus Steropoid.es E. Hitchcock. (Like Sterojnis, a Cyclo)is.) Steropoides E. Hitchcock, '45b, p. 24. Sterojiezoimi E. Hitchcock, '48, p. 182. Trident'qjes E. Hitchcock, '58, p. 88 (to replace Steropezoum) . Generic characters. Bipedal, tetradactyl, subdigitigrade to semiplautigrade. Tarsus sloping upward so that the impression often ends in ridge.s and furrows. The hallux is rotated backward so as to be in line with digit IV. The members of this genus are very similar to those of Sillimanius especially to S. tetradacti/Ins E. Hitchcock. Steropoide>> eJcr/an.'i may be taken as the type. Steropoides elegans E. Hitchcock. Steropoides elegans E. Hitchcock, '45b, p- 24. Steropoides elegantior E. Hitchcock, '45b, p. 24. Steropezoum elegans E. Hitchcock, '48. p. 183, pi. 5, fig. 2. Steropezoum elegantius E. Hitchcock, '48, p. 184, pi. 5, fig. 3. Tridentip)es elegans E. Hitchcock, '58, p. 00, pi. 15, fig. 2 ; pi. 45, fig. G ; pi. 52, figs. 8,11. Specific characters. Pes: divarication of digits I and 11. 75°; of II and III, 05°; of III and IV, 65°; of II and IV, 125°. Length of digit 1, .040 m.; of II, .040 m.; of HI, .071 m.; of IV, .(I5(i m. Distance between lateral tips, .089 m. Length of heel impres- sion, .064 m. Widtli of heel, .013 m. Length of foot, .135 m. Length of step, .250 to .500 m. Width of trackway, .178 m. 524 RICHARD SWAXN LULL ON This species is much smaller than the better known N. nKjensi, h\\{ very similar to it in form. Type specimen, no. jf, of the Ilitchcook cabinet, is on red shale from Turner's Falls, Massachusetts. Steropoides ingens E. Hitchcock. Steropoides ingens E. Hitchcock, '45b, p. 24. Sillimanius adamsCtnus E. Hitchcock, '45b, p. 24. Steropezoum ingens E. Hitchcock, '48, p- 182, pi. 5, fig. 1. Ornithopus adamsamis E. Hitchcock, '48, p. Wl, pi. 7, fig. 5. Tridentipes ingens E. Hitchcock, '58, p. 89, pi. 15, fig. 1. Specijic characters. Pes : divarication of digits I and H, 80° ; of II and HI, 50° ; of III and IV, 58° ; of II and IV, 107°. Length of digit I, .127 m.; of II, .203 m.; of HI, .242 m.; of IV, .145 m. Distance between lateral tips, .282 m. Length of heel impres- sion, .230 m. Length of foot, .460 m.; of the step, 1.020 to 2.020 m. This is a large but very peculiar track as the metatarsal bones, the so called heel, make a broad and deep impression shoaling out toward the rear as though that segment of the leg were borne at a decided slant. The digits are long and very slender or else the mud has slipped into the track as soon as the foot was withdrawn. There are no digital pad impressions or other characters preserved. Tlie foot is more lacertilian than avian and is totally unlike the typical dinosaurian tracks. Yet from its bipedal gait and the number of digits, the maker of the impression must have been a dinosaur, though unlike any form whose skeletal remains are known. The type specimen is no. j|, of the Hitchcock cabinet, on gray micaceous sandstone, from Gill, Massachusetts. It is also found on the White hall. New Jersey, slab of red shale, in the Rutgers college museum. Steropoides infelix Hay. Steropoides infelix 0. P. Hay, : 02, p. 552 (to replace elegantior a name already used within the genus) . Tridentip)es elegantior E. Hitchcock, '58, p- "•'(), pi. 15, fig. 3; pi. 45, fig. 1 (not Steropezoum elegantius, '46) . Specific characters. Pes: divarication of chgits I and II, 108°; of II and 111,32°; of III and I\', 44°; of II and IV, 75°. Length of digit I, .010 m.; of II, .015 m.; of III, .029 m.; of IV, .023 m. Distance between lateral tips, .028 m. Length of heel impres- sion, .018 m.; of foot, .045 m. Length of step, .135 m. Width of trackway, .045 m. FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 525 Type, no. ^, of the Hitchcock cabinet, on reddish shale from Turner's Falls, Massachusetts. Steropoides loripes (K. llitclicock). Ornithopus loripes E. Hitchcock, '48. p. H'o. pi. 8, fig. 3. Tridentipes ins'ujnls E. Hitchcock, '58, p- •*!, pi. 15, fig. 4 ; pi. 45, fig. 3 ; pi. 47, fig. 2. Specific characters. Pes : divarication of digits I and H, 55° ; of II and III, 45° ; of III and IV, 50° ; II and III, 95°. Length of digit I, .081 m.; of H, .109 m.; of III, .135 m.; of IV, .109 m. Distance between lateral tips, .160 m. Length of heel impression varies np to .050 m. Length of foot, .152 to .178 m. Length of step, .400 to .567 m. Width of trackway, .317 m. A long limbed, blunt clawed form ; subdigitigrade. Type specimens, nos. l- and ~, of the Hitchcock cabinet, on micaceous sandstone, from near Montague, Massachusetts. Steropoides uncus (E. Hitchcock). Tridentipes vnciis E. Hitchcock, '58, p. 91, pi. 15, fig. 5 ; pi. 46, fig. 1. Specific characters. Pes: divarication of digits I and II, 22°; of II and HI, 48°; of HI and IV, 44°; of II and IV, 90°. Length of digit I, .028 m.; of II, .043 m.; of III, .056 m.; of IV, .036 m. Distance between lateral tips, .056 m. Length of heel, .028 m.; of the foot, .082 m. Length of step, .215 to 227 m. Width of trackway, .155 m. *S'. uncus differs markedly from the other members of the genus in the short step and wide trackway, and also in the position of the hallux wliich is only semirotated. The type is no. f, of the Hitchcock cabinet, from Turner's Falls, Massachusetts. Genus Lagunculapes E. Hitchcock. (Flask foot.) Lagunculapes E. Hitchcock, '58, p. 132. Generic characters. Bipedal, digitigrade, tetradactyl, with the clawless chgits widely radiating and more or less flask- or club-shaped, dilating toward their tips; clawless. There is but one species, L. latus E. Hitchcock. Lagunculapes latus E. Hitchcock. Lagunculapes latus E. Hitchcock, '58, p- 132, pi. 24, fig. ] ; pi. 45, fig. 4. Specific characters. Pes: divarication of digits I and II, 50°; of II and III, 70°; of 526 RICHARD SWANN LULL ON III and IV, 65°; of 1 and IV, 180°. Length of digit 1, .013 m.; of 11, .014 m.; of III, .020 m.; of IV, .015 m. Length of foot, .022 m. Width of foot, .032 m. Length of step, .076 m. Width of trackway, .076 m. Hitchcock considers this form a batrachian because of the similarity to Proteus in number of toes and absence of claws. He also likens the form of the toes to that of the toes of tlie lizard, Anolis. The bipedal walk would seem to associate the form with the Reptilia though it hardly agrees with our conception of a dinosaur. Type, no. ||, of the Hitchcock cabinet, on gray shale from Turner's Falls, Massachusetts. Forms occasionally quadrupedal. Genus Xiphopeza E. Hitchcock. (Sword foot.) Xiphopeza E. Hitchcock. '48. p. 239. fTCiieric characters. Quadrupedal, possibly not habitually so ; plantigrade ; the tetra- dactylous pes much larger than the manus which, in the known specimens, impresses but three digits. Xiphopeza triplex E. Hitchcock. Xiphojiezn triplex E. Hitchcock. '48, p. 239, pi. 15. fig. 8; '58, p. 113. pi. 20. fig. 6; pi. 52, figs. 3. 4. 6. Specific characters. Pes: divarication of digits I and II. 90°; of II and III, 40°; of III and IV, 50°. Length of digit I, .013 m.; of II, .020 m.; of III, .038 m.; of IV, .028 m.; of the heel. .030 m. Length of foot, .066 m. Distance between lateral tips. .038 m. Breadth of heel, .012 m. Length of step, .102 m. Width of trackway, .115 m. Manus: but three digits impressing, aJiout .010 m. in length. Type specimen, no. ||, of the Hitchcock cabinet, on gray shale from Turner's Falls, Massachusetts. Genus Tarsodactylus E. Hitchcock. (Toed tarsus.) Tarsodactylus E. Hitchcock. '58. p. 98. Generic characters. Quadrupedal, digitigrade; manus pentadactylous, pes tetra- dactylous with broad digits and somewhat acuminate claws but without phalangeal pads. Tail trace present. A very rare group. FOSSIL FOOTPinXTS OF TIIK JURA-THIAS. 527 Tarsodactylus caudatus K. llitelicock. Tarsodactylus miidatm E. Hitclicock. '58. p. '•»'■•, pi- 17. fig. 4; pi. 06. tig. 2. This form approximates Anomoepm minimus closely in size iiiid proportions, being but little larger. It may prove identical. Type specimen, no. ^. of the Hitchcock cabinet, on shale from Turner's Falls. Massa- chusetts. Tarsodactylus expansus C. II. Hitchcock. Tarsodactylus expansus C. H. Hitchcock, '66, p. ■3<»l-3()2. Specific characters. Pes: divarication of digits 11 and Ul, 2-5°; of HI and l\\ 50°; of n and IV, 75° to 80°. Length of digit H, .025 m.; of HI, .037 m.; of n', .02S m. Length of hallux claw, .005 m.; distance from foot, .010 m. Distance between lateral tips, .038 m. Length of foot, .043 m. Length of step, .127 to .178 m. Width of track- way, .140 m. Manus : divarication of digits I and H, 30° ; of H and HI, 20° ; of III and IV, 25° ; of IV and V, 25° to 30°; of I and V, 100°. Length of digit I, .012 m.; of H, .020 m.; of HI .019 m.; of IV, .015 m.; of V, .0095 m. Distance between lateral tips. .025 m. Cau- dal trace, slight. This form differs from T. caudatus in the greater divarication of the toes; in its smaller size ; in its irregular mode of walking as compared with caudatus, and the fact that it does not trail the toes as does the latter. This feature may be entirely due to the animal's gait at the time the impressions were made and hence may be of little impor- tance as a distinction. The type specimen is from near Greenfield, Massachusetts, and is preserved in the cabinet of Prof. C. H. Hitchcock, at Dartmouth college, Hanover, New Hampshire. Genus Harpedactylus E. Hitchcock. (Sickle toed.) Harpedactylus E. Hitchcock, '45b, p. 24. Generic characters. Quadrupedal, tetradactylous, plantigrade; heel long, digits sometimes curved inward, sickle-like. This genus represents a group of mud tracks, at least two species of which seem referable to Anomoepodoid forms, wliile the third, //. crassiis, is not so typical. The entire group seems to be of doul)tful validity. Harpedactylus tenuissimus K. Hitchcock. Harpedactylus temiissimus E. Hitchcock, •45b, p. 24. Harpedactylus gracilis E. Hitchcock, '58, p. 112, pi. 20, fig. 4 ; pi. 52, fig. 5. 528 RICHARD SWANN LULL ON The kaown specimens are those of seated animals about the size and proportions of Anomoepus minimum E. Hitchcock, and possibly referable to that species. The type specimen is no. f|, of the Hitchcock cabinet, from Turner's Falls, Massachu- setts. It seems further possible that Plectropternu (/lyiriJls E. Hitchcock, may also belong here, as well as P. /'uieans E. Hitchcock. Harpedactylus gracilior E. Hitchcock. Ildrpedactylus ijracUior E. Hitchcock, '65, p- 1-i, pi. o, fig. 2. This form is very similar to the preceding species except that it is much smaller and the manus is unknown. It is inipossible to refer it to any known Anomoepus because of its size, but its affinities are probably with that genus. H. f/racifio)' is known from but two specimens, nos. H and ^, of the Hitchcock cabinet, both from Turner's Falls, Massa- chusetts. Harpedactylus crassus E. Hitchcock. Harpedactylus crassus E. Hitchcock, '65, p. 12, pi. 3, fig. 1. This species is based upon a single badly worn specimen showing both manus and pes tracks. It is a characterless track of doubtful affinity. It could, however, have been formed by Anomoepus scanibus as the size and proportions of fore and hind feet agree ; but tlie subsequent slipping of the mud has distorted the impression very much. The type specimen is no. f|, of the Hitchcock cabinet, on gray sliale ; type locality unrecorded. Subclass Synapsida Osborn. Order TESTUDINATA. Quadrupedal forms, generally with short stride and wide trackway indicating short legged, broad bodied creatures. Often with longitudinal traces which may have been made by dragging tail, limbs, or plastron. The reference of the following genera to this order is by no means certain, being based upon President Hitchcock's opinion. Genus Ancyropus E. Hitchcock. (Anchor foot.) Ancyropus E. Hitchcock, '45b, p. 24; '58, p. 138. Generic characters. Quadrupedal, plantigrade. Pes tetra- or jDcntadactylous, hallux semirotated, the other digits turned outward very strongly. Manus tetradactylous, dig- FOSSIL FOOTPRINTS OF THE JURA- TRIAS. 529 its as iu pes, Ijut much slenderer in proportion to its length. No pad nor claw impres- sions are presei-ved. In several of the specimens it seems as though the foot which made the impression had lain on its side rather than in the normal position, which may account for the pecu- liar form of the track. Ancyropus heteroclitus E. Hitchcock. Ancyyopns heterodltm E. Hitchcock, '45b, p. 24; '58, p. 139, pi. 25, fig. 3-4; pi. 53, fig. 1-2. Ancyropvsjacksonianus E. Hitchcock, '45b, p. 24. SjJeclfic characters. Pes : length of foot, .051 m. Breadth across the toes, .033 m.; across the heel, .020 m. Average length of digits, about .010 m. Length of step, .063 m. Width of trackway, .165 m. Manus: length, .051 m.; average length of digits, .007 to .00is abiionnis E. Hitchcock, '45b, p. 25; '58, p- 105, pi. 17, fig. 9; pi. 45, fig. 7. This form is much larger thau the following species. Type specimens, nos. -\- and ^, of the Hitchcock cabinet, from Turner's Falls, Massa- chusetts. Typopus gracilis E. Hitchcock. TyjJopus gracilis E. Hitchcock, '58, p. Ul6, pi. 17, fig. 1(1. Founded upon a single track and its counterpart on the red shale of Weathersfield, Connecticut ; nos. ^ and f| of the Hitchcock cabinet. COKCLUSIONS. The creatures, the record of whose existence has remained impressed upon the ancient shales and sandstones, may be divided into two groups in accordance with their mode of progression : those of bipedal and those of quadrupedal gait. The former, it may be safely assumed, are. in all probability, dinosaurs, for aside from man, many birds, and some modern lizards, they are the only vertebrates whose gait when erect could have been a true walk or run with alternating steps, which without exception, the bipedal tracks show, there being no instance of the record of a jumping form. The presence of birds in the new red sandstone has not been proven, lizard.s are never hahituaJ bipeds, man is clearly out of the question, hence by elimination we narrow the possible origin of such tracks down to the dinosaurian forms. This conclusion is strengthened by the pres- ence of the fossil bones of the Anrhindiiridiie, a family of primitive carnivorous dinosaurs having affinities with the Megalosauria. The most abundant <)i the tracks are attributable to members of that family, creatures ranging in size from about seven to fourteen feet, so trul\ liipedal that the manus and tail never impress. The pes is tetradactvl but only exceptionally does the claw of the strong grasping hallux leave a mark. The claws are rather pointed and the whole foot is very bird-like. These footprints form a natm-al group to which the generic name of Ancliisauripus is given and which corresponds to the family Aiicliiaannchte. Allied to Ancliisauripus is another carnivorous form whose foot is more specialized than that of the t'ormei- in the enfeeblement of the hallux and increase of weight which has rendered the foot Hatter and its pads more complex. This creature, Gigandipus, reminds one strongly ot the Jurassic Allosaurus though in the latter the claws were probably more trenchant and the wliole foot more efficient as a grasping organ, (iigandi- pus, known from but one specimen, shows a sinuous caudal trace. The dragging of the .■)44 KICIIARD SWANN LULL ON tail prohiiljly was nut haljitual, but occurred ouly wlien the animal \va.s slowing down before stopping. Another abundant genus is Grallator characterized Ijy very long limbs and small, compact feet without an impressing hallux and with no tail trace. The proportions of length of limbs to those of feet are the same as in the bustards and the forms which made the tracks were probably aberrant carnivores of habits somewhat similar to those of wad- ing birds, possibly feeding upon feebler reptiles and amphibians, or on fish. In consider- ing the probable relationship of this genus to genera known from their skeletal remains one is reminded strongly of Ornithomimus. a Cretaceous Compsognathoid dinosaur. Grallator comprises for the most part, small forms, the smallest species, G. ijniciris, indicating a creature l)ut two thirds the size of Conipsognathus. the smallest known dino- saur, whose dimensions may be compared with those of the ilomestic cat. Among the habitually bipedal forms, those which never impress the mauus, is one group to which the name Eubrontes has been given. It includes larger and heavier forms than Anchisauripus with more l)lunted claws, but Hitchcock included it with the latter under the name Eubrontes and the later name Brontozoum. The two genera are so different in character that the present author is constrained not only to separate them gen- erically but ordinally as w^ell. for the lack of a grasping hallu.x;, the heavy, slow moving- tread, and the blunter claws are surely not carnivorous characteristics, but seem to point rather to an herbivorous habit of life. It may be that instead of being Orthopod or Pre- dentate dinosaurs the Eulu'ontes represent another group of aberrant Carnivora, which like the condor {Sarcor/Kiiujihiis (/ri/phit.s) because of carrion feeding habits, did not retain the raptorial claws of its predacious allies. The genus Eubrontes wdiile few as to species contains some of the most impressive forms which are fairly numerous as to individuals. Eubrontes gif/anteiis represents an animal of massive proportions and of about twenty feet in length, which is nearly the maximum for American Triassic dinosaurs, though much inferior in size to those of the Jurassic and Cretaceous periods. Dinosaurs beyond question herbivorous in their habits and hence belonging to the order Orthopoda, are the occasion- ally quadrupedal forms which, though walking on the hind feet, placed the fore feet on the ground while sitting. This shows that on both manus and pes the claws are short and rounded and no longer subserve a grasping function. The particular interest which attaches to this fact is that it is the first evidence we have of Orthopoda or Predentate dinosaurs in the Trias, for their skeletal remains are entirely unknown either in this country or in pAU'ope from the rocks of that period. Anomoepus, the most characteristic genus among the herbivorous forms, had a peuta- dactyl manus with rounded claws and a tetradactyl pes with somew^hat longer, but still blunted claws. The hallu.x was but half rotated and therefore ill fitted for grasping and i FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 545 there was a long metatarsus, or heel, on which the creature rested. The tail sometimes dragged just before the owner came to rest but at other times was held clear of the ground as a counterpoise to the anterior part of the body as in other genera. Anomoe- pus represents a group of small, lightly built creatures ranging in size from .1. minimus, about three feet in length, to A. crassus, a New Jersey form, six feet long. They are among the most numerous and interesting of all of the ichnite genera with the exception of Anchisauripus. The genus Fulicopus, which the writer has separated from the preceding group, shows a greater amount of weight borne on the hind limbs while sitting, the manus rest- ing but lightly as with the kangaroo. The feet resemble those of Anchisauripus more than those of Anomoepus, there being less divarication or diverging of the digits, though the position of the hallux is as in the latter genus. A curious heart shaped impression frequently occurs just behind and between the impressions of the heels and tliis was attributed by Hitchcock to the end of a truncated tail, but the writer believes it to have l)een made by a callosity beneath the apposed extremities of the ischial bones. Hypsilo- phodon, of the Wealdeu of Europe, most nearly suggests the probable skeletal characters of the Anomoepodoid forms and as Professor Osborn has shown, presents the most primi- tive characters of any known Orthopod. It is difficult to conjecture the probable habits of Anomoepus, other than that the animals were herbivorous. They pi-obably came to the mud flats mainly for breeding purposes as their tracks very frequently exhibit a dis- tinct sexual dimorphism between the footprints of the two individuals. A very striking though rare form, Otozoum, has been placed by the present writer among the Orthopoda although the structure of its foot is unlike that of any known dino- saur. Otozoum is probably bipedal though there is a possibility that the great pes may have obliterated the track of the much smaller manus. The foot is plantigrade, tetra- dactyl, with all of the digits pointing forward and with rounded pellet-like claws and a broadly expanding web or fleshy pad extending some distance beyond the ends of the digits. Its probable function was that of supporting the creature on soft mud rather than a natatorial one. The phalangeal formula of the pes is typically dinosaurian, while that of the manus, 2. 3. 3. 3. 3, is amphibian or cotylosaurian and would be absolutely unique in a dinosaur. The manus is rarely seen and is so obscure that there is a reasonable doubt as to the correctness of its interpretation. In one instance a dragging tail is shown which is absent in all other specimens and which is evidence in favor of the belief that the animal is a biped. Otozoum has the largest track of all, measuring twenty inches in length, but the author has no conception of the appearance of the creature itself. Among the so called leptodactylous or narrow toed tracks, are many made by bipedal forms which were doubtless dinosaurs, some carnivorous, and some, judging from the ')46 RICHARD SWANN LULL ON manus which is occasionally seen, herbivorous in habits. The subsequent slipping of the mud after the withdrawal of the foot has obliterated most of the morphological characters from the impressions. Some of the leptodactylous forms have been identified with the better known genera and species, others which cannot be so identified because of their obscurity may nevertheless be identical with known forms, while still (jthers evidently do not occur elsewhere. It is a notable fact that while the number of genera and species which have been erected upon these impressions is large, the number of individuals repre- sented is proportionately small and these are mainly from one or two localities. Of the truly quadrupedal forms the most interesting is Batrachopus. whose long- limbs, tetradactyl, plantigrade pes with acuminate claws, and phalangeal formula of 2. 3. 4. 5, and whose pentadactyl manus are such as one would expect to find in the dinosaurian ancestor. It seems possible therefore, that Batrachopus represents a persistent type whose affinities are near the dinosaur stem form and which should be classed with Kadalio- saurus in the superorder Diaptosauria of Osborn. Batrachopus may have been a true dinosaur which had retained, among other primitive characters, the ancestral ({uadrupedal gait. The mode of progression was a true walk like that of a mammal and not the sprawling crawl of modern reptiles. Batrachopus included small forms of carnivorous habits. There remain other quadrupedal forms, generally of small size, whose tracks, aside from the number of digits, size of the foot, and the length of limb, afford almost no data whereon to base a theory as to their affinities. Professor Osborn has likened ichnological interpretation to the deciphering of ancient cuneiform inscriptions which are utterly unintelligible unless one possesses the key. That the key to the deciphering of the dinosauroid tracks has been found seems evident, but in the attempt at the interpretation of the obscurer quadrupedal footprints the student is still very much in the dark. Amherst, Mass. FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 547 BiBLIOGKAPHY.' Adams, C. B. "46. Notice of a .small ornithichnite. Amer. journ. of sci. and arts, ser. 2, vol. 2, p. 215-216, text fig. 1-2. Baur, G. "87. On the phylogenetic arrangement of the Saurop.sida. Journ. of morphology, vol. l,p. 93-104. Beasley, H. C. "96. An attempt to classify the footprints in the new red sandstone of this [Liverpool] district. Proc. Liverpool geol. soc, 37th session, vol. 7. pt. 4, p. 391-409, pi. 1-3. Beckles, S. H. '51. On suppo.sed casts of footprints in the Wealden, Quart, journ. geol. soc. London, vol. 7, p. 117. "54. On the ornithoidichnites of the Wealden. Quart, journ. geol. soc. London, vol. 10, p. 450-464, 1 text fig. '59. ()u fossil footprints in the siindstone at Cummingstone. Quart, journ. geol. soc. London, vol. 15, p. 461. "62. On some natural easts of reptilian footprints in the Wealden beds of the Isle of Wight and of Swanage. Quart, journ geol. soc. London, vol. 18. p. 443-447, text fig. 1-4. Bernhardi, Reinhard. '34. [( In tracks found near Ilildburghausen.] Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1834, p. .641-642. Bouv6, T. T. "59. [On priority of discovering footprints in the Connecticut valley.] Proc. Boston soc. nat. hist., vol. 7, p. 49-53. Brodie, P. B. '60. On the occurrence of footsteps of Chirotherium in the upper Keuper of Warwickshire. Ann. and mag. nat. hist., .ser. 3, vol. 5, p. 4. Buckland, W. "28. Note sur des traces de tortues observfies dans le gr6s rouge. Ann. des sci. nat., vol. 13, p. 85-86. '36. The Bridgewater treatises on the power, wisdom, and goodness of God as manifested in the creation. Treatise 6. Geology and mineralogy considered witli reference to natural theology. London: 2 vols., 8vo. ("Fossil footsteps," vol. 1, p. 199-201.) "39. An account of the footsteps of the Cheirotherium and five or six smaller animals in the stone quarries of Storeton hill, near Liverpool. Notices and abstracts of communications to Briti.sh as,soc. adv. sci., Newcastle meeting, 1838, vol. 7, p. 85. '58. The Bridgewater treatises on the power, wisdom, and goodness of God, as manifested in the creation. Treatise 6. (jeology and mineralogy considered witli reference to natural theology. 3d ed., London : 2 vols., 8vo., illus. Cook, G. H. '85. [List of species found at Whitehall, New Jersey.] Geol. surv. of New Jensey, ann. rept. state geologist for 1885, p. 96. Cope, E. 1). "67. [Account of extinct reptiles which approach birds.] Proc. acad. nat. sci. Philadelphia, 1867, p. 234-235. Cotta, B. ■39a. Notitz fiber thierfahrteu im bunten sandstein bei Polzig zwischen Ronneburg und Weis.senfels. Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1889, p. 10-15. '39b. Ueber thierfahrteu im bunten sandsteine bei Polzig im Altenburgischen. Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1839, p. 617. Croiset, — . . '35-'36. [On the fmitprints of He-isburg. ) Hull. soc. g6ol. de France, vol. 7, p. 259-260. Cunningham, J. '38a. [On the footprints of Liverpool.] London and Edinburgh philos. mag., vol. 14, p. 148. ' Including nearly all of the literature upon Triassic and Jurassic footprints. 548 RICHARD SWANN LULL ON '38b. [An account of the footsteps of the Chirutherium.] Proc. geol. soc. London, vol. 3, p. 12-14. '46. On .some footmarks [of birds] and other impressions observed in iIil- new red sand.stone quarries of Storton, near Liverpool. Quart, journ. geol. soc. London, vol. 2, p. 410. Cushman, J. A. :04. A new footprint from the Connecticut valley. Amer. iieoloiiist, vol. :!3. p. l'>4-15(i, pi. (>, {Otoupficpus maf/nificus.) Dana, J. D. '95. Manual of geology. 4th ed., New York : 8vo ; 1088 pp., illus. (See p. 752-753.) Daubr6e, A. '57. Decouverte de traces de pattes de quadrupedes dans le gres bigarrfi de Saints Valbert, pres Luxe\ul (Haute-Sa6ne). Comptes rendus hebdomadaire.s des stances de Tacad. des sci., Paris, vol. 45. p. 646-648. '58. Note sur la decouverte de traces de pattes de quadrupedes dans le gr6s bigarrfe de Saiut-Valbert, pres Luxeuil (Haute-Saone). Bull. soc. geol. de France, .ser. 2, vol. 15, p. 218-221. Deane, James. '44a. On the fossil footmarks of Turner's Falls, Massachu.setts. Amer. journ. sci. and arts, vol. 46, p, 73-77, pi. 1-2. Abstract of, in Quart, journ. geol. soc. London, vol. 1, 1845, p. 141-142. '44b. On the di.scovery of fossil footmarks. Amer. journ. sci. and arts, vol. 47, p. 381-390. '44c. Answer to the " Kejoinder" of Prof. Hitchcock. Amer. journ. sci. and arts, vol. 47, p. 399-401. '45a. Description of fossil footprints in the new red sandstone of the Connecticut valley. Amer. journ. .sci. and arts vol. 48, p. 158-167, pi. 3. '45b. lUu-strations of fossil footmarks. Bo.ston journ. nat. hi.st., vol. 5, p. 277-284, text fig. 1-3. '45c. Notice of a new species of batrachian footmarks. Amer. journ. .sci. and arts, vol. 49, p 79-81, text fig. A-B. '45d. Fossil footmarks and ram-drops. Amer. journ. sci. and arts, vol. 49, p. 21.3-215, one page of tigs. "47a. Notice of new fossil footprints. Amer. journ. .sci. and arts, ser. 2, vol. 3, p. 74-79, text fig. 1-4. '47b. Fossil footprints. Amer. journ. sci. and arts, ser. 2, vol, 4, p. 448—449. '48. Fossil footprints of a new species of quadruped. Amer. journ. sci, and arts, .ser. 2, vol. ■>, p. 40-41, 1 text fig. "47-'50. Fossil footprints of Connecticut river. Jouru. acad. nat. sci. Philadelphia, ser. 2, vol. 2, p. 71-74, pi. 8-9. '56. On the sandstone fo.ssils of Connecticut river. .Journ. acad. nat. .sci. Philadelphia, ser. 2, vol. 3, p. 173-178, pi. 18-20. '61. Ichnographs from the sandstone of Connecticut river. Boston : 4to, 61 pp., 46 pis. Degenhardt, — . '40. [Footprints of birds from Oiva, province of Socorro, Mexico.] Neues jahrb. f. mineral., geogn., geol., u. petrefak- tenkunde, 1840, p. 485. DoUo, L. '83. Troisifeme note sur les dinosauriens de Berni.ssart. Bull. mus. roy. d'hist. nat de Belgique, vol. 2, p. 85-126, pi. 3-5. Duncan, H. '31. An account of the tracks and footmarks of animals found impressed on sand.stone in the quarry of Corncockle Muir, in l)umfries.shire. Traas. roy. soc. Edinburgh, vol. 11, pt. 1, p. 194-209, pi. [8]. Edwards, A. M. '95. Ornithichnites and jaw bone from the Newark sandstone of New Jersey. Amer. journ. sci., .ser. 3, vol. 50, p. 346. Egerton, P. G. '38. [On the footprints of Liverpool.] London and Edinburgh philos. mag., vol. 14, p. 150. Emerson, B. K. '98. Geology of Old Hampshire county, Massachusetts, comprising Franklin, Hampshire, and Hampden counties. Monog. U. S. geol. surv., vol. 29, xxi -|- 790 pp., 35 pis. (Ichnology, p. 400-404.) FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 549 Englehaidt, — . ■37. Ueber die formation, in welcher die tatzen-abdiiicke vorweltlicher tliiere in dev nahe von Hildburghansen auf- treten, und iiber das vorkommen dieser abdriieke. Neues jahib. f. mineral., geogn., geol., u. petrefaklenkunde, 1837, p. .379-388. Eyerman, J. '86. Footprints of the Tria.ssic sandstone (Jura-Trias) of New Jersey. Amer. journ. sci., .ser. 3, vol. 31, p. 72. "89. Notes on geology and mineralogy. Proc. acad. nal. sci. Pliiladelpliia, 1889, p. 32-35. Field. \i. ■60a. ( >rnitliichnites, or tracks re.sembling those of birds. Amer. journ. .sci. and arts, ser. 2, vol. 29. p. :i01-3ti3. ■60b. I hnithichnite.s. Proc. Amer. a&soc. adv. sci., 13th meeting, Springfield, p. 337-340. '60c. [The footmarks of the Oonnectirut river sandstones.] Proc. Boston soc. nat. hist., vol. 7, p. 31(i-3I7. Gaudry, A. '90. Las enchainements du moude animal dans les temps gfiolo.giques. Fnssiles secondaires. Paris: 8vo. ; illus. (On Chirotherium.) Oeinitz, H. B. '63. Ueber thierfahrten und cruslaceen-reste in der unteru Dyas. Neiies jahili. f. mineral., geol., u. palaeontol., 1803, p. 118. (SeeOppel, 1862.) Gervais, Paul. '57a. Sur des empreiutes de pas laissees par plusiers e.speces d'animau.x dans le terrain Triassi(iue des environs de Lodeve. Comptes rendus hebdomadaires des seances de I'acad. des sci., Paris, vol. 45, p. 7()3-7(iu. '57b. [(.)n Chirutheriuin bo.iihi and tridactyl tracks of Lodeve.] L' Institute, vol. 25. Giebel, C. G. '47-'56. Fauna der vorwelt mit steter beriicksichtigung der lebenden thiere. Leipzig; 5 vols. (See vol. 1, pt. 2, p. 34.) Grabbe, H. '81. Neue funde von saurier-f.ahrten im Wealdensandsteine des Buckeburges. Verhandl. cl. iiaturhist. verein. d. preass. Hheinlande und Westfalens, vol. 38, p. 161-104. Haidinger, W. '41. Ueber eine neue art von vorweltlichen thierfahrten. Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde. 1841, p. 546-548, pi. 10. Harkness, P. ■50a. On the position of the impres.sions of footsteps in the Bunter sandstone of l)umfrie.s-shire. Ann. and mag. nat. hist., ser. 2, vol. 6, p. 203-208. '50b. Notice of a tridactylous footmark from the Bunter sandstone of Weston Point, Cheshire. Ann. and mag. nat. hist., ser. 2, vol. 6, p. 441-442. '51. Notice of some new footsteps in the Bunter sandstone of I)umfrie.s-shire. Ann. and mag. nat. hist., ser. 2, vol. 8, p. 90-95. Hawkshaw, — . '43. New red .sand.stone of Lymm in Cheshire. L'In.stitute, vol. 11. Hay, O. P. :02. Bibliography and catalogue of the fo.ssil Vertebrata of North America. Bull. U. S. geol. surv., no. 179, p. 1-868. (See p. 538-553.) Hitchcock, C. H. '55. Impressions (chiefly tracks) on alluvial clay, in Hadley, Mass. Amer. journ. sci. and arts, ser. 2, vol. 19, p. 391-396. '65. [Editorial notes and some new descriptions.] In Edward Hitchcock's Supplement to the ichnology of New England (see E. Hitchcock, '65). '66. Description of a new reptilian bird from the Trias of Massachu.setts. Ann. lyceum nat. hist. New 'i'ork. vol. 8, . p. 301-302. 550 KICHARI) SWANX LFLL ON ■71. [A(^ciiiiiit and I'oiiiiilfte list nf the Iclmu/.oa of tin- CdiiMertk'Ut valley. J Walling ami (iray's urticial topograph- ical atlas of Massachusetts, p. xx-xxi. '73. Footprints in the rocks. I'op. sci. monthly, vol. ;J, p. 428-441, text tiii. 1-T. ■89a. [Remarks on A. Wanner's paper on the discovery of fossil tracks in the Triassic of York county, I'a. | Proc. Amer. assoc. adv. sci., .37th meeting, Cleveland, 1888, p. 180. '89b. Recent progress in ichnolngy. Proc. Bo.ston soc. nat. hist., vol. 24, p. IIT-PJT. Hitchcock, Edward. '36. Ornithichnology. — Description of the footmarks of birds, (Ornithichnites) on new red sandstone in Massachu- .setts. Amer. .journ. sci. and arts, vol. 29, p. 307-340, pi. [1] fig. 1-20, 2.3-24; pi. [2], tig. 21-22, pi. [3]. '37a. Ornithichnites in Connecticut. Amer. journ. .sci. and arts, vol. 31, p. 174-175. '37b. Fossil footsteps in sandstone and graywacke. Amer. journ. sci. and arts, vol. 32, p. 174-17(). '41. Final report on the geology of Massachusetts. Northampton: 4to ; 11 -f 831 pp., illus. (See p. 458-525, pi. 29-51.) '43. Description of live new species of fossil footmarks, from the red sandstone of the valley of Connecticut river. Reports of the first, second and third meetings of assoc. of Amer. geologists and naturalists, p. 254-264, pi. 11. '44a. Report on ichnolithology, or fossil footmarks, with a description of .several new species, and the coprolites of birds, from the valley of the Connecticut river, and a supposed footmark from the valley of Hiid.son river, Amer. journ. .sci. and arts, vol. 47, p. 292-322, pi. 3-4. (Abstract in Neues jahrb. f. mineral., etc., 1845, p. 753-757.) '44b. Rejoinder to the preceding article of Dr. Deane. Amer. journ. sci. and arts, vol. 47, p. 390-399. ( Reply to J. Deane, '44b.) ■45a. Extract of a letter from Prof. E. Hitchcock, embracing miscellaneous remarks ujion fossil footmarks, the lincolnite, &c. Amer. journ. sci. and arts, vol. 48, p. 61-65. '45b. An attempt to name, classify, and describe, the animals that made the fo.s.sil footmarks of New England. [Abstract.] Proc. 6th annual meeting assoc. Amer. geologists and naturalists. New Haven, Conn., April, 1846, p. 23-25. '47. Description of two new siiecies of fossil footmarks found in Mas.sachusetts and Connecticut, or, of tlie animals that made them. Amer. journ. sci. and arts, ser. 2, vol. 4, p. 46-57, text fig. 1-3. '48. An attempt to discriminate and describe the animals that made the lo.s.sil footmarks of the United States, and especially of New England. Mem. Amer. acad. arts and sci., new ser., vol. 3, p. 129-256, table, pi. 1-24. '55. Shark remains from the coal formation of Illinois, and bones and tracks from the Connecticut river .sandstone Amer. journ. sci. and arts, .ser. 2, vol. "20, p. 416-417. '56. Description of a new and remarkable species of fossil footmark, from the sand.stone ni 'rnrner's Falls, hi the Connecticut valley. Amer. jimrn. .sci. and art.s, ser. 2, vol. 21, p. 97-100, 1 text fig. '58. Ichnology of New England. A report on the .sand.stone of the Connecticut valley, especially its fo.ssil footmarks, made to the government of the Connnonwealth of Massachusetts. Boston : 4to ; xii -)- 220 pp., 60 pis. '61. Remarks upon certain points in ichnology. Proc Amer. a.s.soc. adv. sci.. 14th meeting. Newport, 1860, p. 144- 1.56, text fig. 1-4. '63. New facts and conclusions respecting the fossil footmarks of the Connecticut valley. Amer. journ. sci. and arts, ser. 2, vol. 36, p. 46-57, text fig. 1-2. '65. Supplement to llie Ichnology of New England. Boston : 4to ; x -f 90 pp., 20 pis. '66. SupplemeiU to the Ichnology of New England. Proc. Amer. acad. arts and .sci.. vol. 6. )>. 85-92. Horn.stein, K. '76. [On VhirotherhiDi ijeinitzi of Karlshafen.] Neues jahrli. f. mineral., geol., 11, ])alaeontol., 1876, )i. 923-924. von Humboldt, A. '35. Note sur des empreintes ntoli>gischc mitthcilungen aus dena museum des koniglichen bayerischen staates, pt. 2, 1862, p. 121-125, pi. 30. Stuttgart. {Ichiiites lithoijriiphicns possible track of Archacojitcryx.) Osborn, H. F. : 00. Keconsideration of the evidence for a common dinosaur-avain stem in the Permian. Amer. nat., vol. 34, p. 777- 700, text fig. 1-12. ; 03a. The reptilian subclasses Diapsida and Synapsida and the early history of the Uiaptosauria. Mem. Amer. mus. nat. hist., vol. 1, pt. 8. p. 451-507, text fig. 1-23. : 03b. Ornitlwlestes hermanni, a new Compsognathoid dino.saur from the upper Jurassic. Bull. Amer. mus. nat. hist., vol. 19, p. 459-464, text fig. 1-3. Owen, Richard. '42. [On footprints of upper new red sandstone of Greensell.] Trans. Cambridge philos. .soc, vol. 7, p. 3.55. Pahst, W. '96. Die thierfilhrten in deni oberrothliegenden von Tambach in Thiiringen. Zeit.schr. d. deutsch. geol. gesellsch. Berlin, vol. 48, p. 808-829, text fig. 1-10, pi. 17-20. Fictet, F. J. ■53-'57. Traite de palfeontologie. 2d ed., Paris: 4 vols., atlas. (See vol. 1, 185.3, p. 406, pi. 20.) I'lieninyer, — . '38. [On footprints of Stuttgart.] Bericht tiber der versamnUung deutscher naturforscher u. iirzte in Prague, 1837, p. 132-133. (.Jucnsiedt, F. A. '52. Handbuch der pelrefaktenkumle. Tiiliingen ; illus. (Seep. 81.) FOSSIL FOOTPRINTS OF THF JURA-TRIAS. 553 '85. Handbueh der petrefaktenkunde. ;W ed , Tiibiiiffen : illus. (See p. 128-133, with figures. A ^;umiiiary.) Rogers, H. D., et nl. '42. Report on the ornithii-huites or footmarks of extinct birds in the new red sandstone of Massachusetts and Con- necticut, observed and de.scribed by Prof. Hitchcock, of Amherst. Ann. and mag. nat. hist., vol. 8, p.235-238 Rumpf, — . '42. [On footprints of Aura on the Saal.] Neues .jahrlj. f. mineral., .seosn., geol., u. petrefaktenkunde, 1842, p. 450-451. '43. [On footprints of Aura on the Saal.] Xenes .jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1843, p. 705-707. Schwabe, S. H. '54. [On the footprints of Chirotherium of Altenburg.] Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1854, p. 569-570. Sickler, F. K. L. '34. Sendschreiben an .T. F. Blumenbach, liber die hochst merkvviirdigen, vor einigen monateii erst entdeckten reliefs der filhrten urweltlicher gro.s.ser unbekannter thiere in den He.ssberger sandsteinbriichen, bei der stadt Hildburg- hausen. Hildburghauseu : 4to. ; 16 pp., illus. '35. [On the footprints of Hessburg.] Neues jahrb. f. mineral., geogn., .neol.. u. petrefaktenkunile. 1835, p. 230-232. '36. Die vorziiglichsten fahrten abdriicke urweltlicher thiei'e, im bunfem sandsteine aus den sandsteinbriichen der umgegend von Hildburghausen. Hildburghausen. Smith, G. V. '84. On further discoveries of the footprints of vertebrate animals in the lower new red .sandstone of Penrith. Quart. journ. geol. .soc. London, vol. 40, p. 470-481, 1 text fig. SoUas, W. J. '79. On some three toed footprints from the Triassic conglomerate of South Wales. Quart, journ. geol. soc. London, vol. 35, p. 511-516, 1 text fig. {Bruntozoum thomasi.) Struckmann, C. '80. Vorlaufige nachricht fiber das vorkommen gro.sser vogelilhnlicher thierfiihrten (Ornithoidichnites) im Hastings .sandsteine von Bad Rehburg bei Hannover. Neues jahrb. f. mineral., geol., u. palaeontol , 1880, vol. 1, p. 124-128, pi. 4. Tylor, Alfred. '62. On the footprint of an Iguanodon, lately found at Hastings. Quart, journ. geol. soc. London, vol. 18, p. 247-253, 2 text figs., and diagrams. Virlet, Th. '35-'36. Note sur les empreintes de pieds d'animaux dans le gres bigarrc des environs de lliidburghausen, en Saxe. Bull. soc. gfiol. de France, vol. 7, p. 220-224, also note on this paper, p. 2fi0. (On the Chirotherium tracks of He.ssliurg.) Voight, F. S. '32. [On the footprints of Hessburg.] Almanach der natur. 1832, p. 137. '35. [On the footprints of He.ssburg.] Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1835, p. 322—326. '36. Weitere nachrichten (iber die Hessberger thierfiihrten. Neues jahrb. f. mineral., geogn., geol., u. petrefakten- kunde, 18.36, p. 166-174, pi. 3. Wagner, — . '60. [Footprints of Chirotherium hurthi uf Harmerz. ] Neues jahrb. f. mineral., geogn., geol., u. petrefaktenkunde, 1860, p. 693. Wanner, Atreas. '89. The di-scovery of fo.ssil tracks, algae, etc., in the Triassic of York county, Pennsylvania. Ann rcpt. geol. surv. Pennsylvania, 1887, p. 21-35, pi. 3-13. Abstract in Proc. Amer. a.s.soc. adv. .sci., 1888, p. 186. '92. Fossil tracks in the Trias of York co.. Pa. Proc. Amer. as.soc. adv. .sci., Washington meeting, 1801. p. 286. (Abstract.) 564 KICHARD SWANN LILT. OX Ward, Ogier. ■40. [On ilic fnotprints of Oreeiiscll]. L' liistitut, 1840, \i. 2II1. Warren, J. ('. ■54. Kcniaiks iin soiuc fossil iiuprcssiiins in the .sandstone roi'ks nf Cuniici-tii-ut river. Bo.^iton: .54 pp., ilhis. '56. [On new reni,irll. 5, p. 2'.I8-30G. Wiejjiuann. A. F. A. '35. 'riiierfjihrlon ini iMintvn .sandsle inc. An/liiv f. naturpi-.sch.. IH:!;'). \nl. 1. p. 127-131, 3'.l.">-;;!l7. Williani.snn, \V. C. '67. On a ('lieiidthciian fcMitprint from the lia.se of the Kenper .■iand.stcine of Daresbury, Che.shire. (iuarl. j(nirn. geol. .SOI'. London, vol. 28, p. ofi-.">7, pi. 0. Winkler, ('. '86. I/hisioirc d' iclinoloyie. Haarlem. (Historical resume of the ichnological .science, p. 1-187 ; footprints of Hessburg in the .Mu.see Teylei-. p. 188-192, pi. l-i) ; impre.ssions in the lithographic limestone of the Miisfie Teyler, p. l'.t.3-200, pi. 11.) Woodworth, .1. B. '95. Three toeil dinosaur Iraeks in the Newark group at Avondale, N. .1. Anier. journ. sci., ser. 3, vol. ."lO, p. 481-482. Vates, — . '38. On the footprinus at Liverpool. London and Edinburgh pliilos. mag., vol. 14, p. 150. von Zittel, K. A. '80-'93. Handbuch der palaeontologie. 4 vols. Munchen nnd Leipzig. (See vol. 3. 18U0, p. 400-411.) Explanation of the Plate. PLATE 72. Figs A and B. Chirotheriinii hnrthi Kaup. Impressions of the right nuinus and pes, X j> with a provisional restoration of the skeleton. Drawn from a photograph of a speeimen in the British nuiseuin (H. 728). Figs. C and 1). GhiruUierium utoretonfiisix. Impre.ssion of tlie right manus and pes. X \- From specimen no. 'iS, in the Hitchcock cabinet. Fig. F;. Otoztnuii iiuiDtiii \\. Hitchcock. Imprint of the right manus. X ]. From the type specimen, no. f^, in the Hitchcock cabinet. The bone restoration is highly conjectural. Fig. F. Ottizimm moodii ¥j. Hitchcock. Impre.ssion of the right pes. X ',. Drawn from a specimen preserved in the Geological museum of Andu>rst college. The specimen has been so trimmed a-s to destroy most of the web. Fig. (i. Ot izouin lUDiidii E. Hitchcock. Imprint of the right pes. x ]. From the specimen no. *,of the Hitchcock cabinet, showing the full development of the web. The broken line ( ) indicates the variation between successive tracks of the .same foot. The skeleton restoration is somewhat conjectural. Signs referring to all the figures: pad and well outline; outline of claws ; outline of variation ; restored outline; broken edge of slab. FOSSIL FOOTPRINTS OF THE .TITRA-TRIAS. 555 Index. (ieneric and specific names regarded a-s synoiiyius are printed iu italics. Tlie asterisk (*) indicates the page upon vlijch the species is figured, while that bearing the description of the form is designated by bold faceil numerals. Aethyopus, 501. lyeliianus, 506. minur, 501. Agriochoerus, 477. AUosaurus, 471, 492, 493, 543. Amblonyx, 506. giganteus, 512, 513. lyeliianus, 506. Amblypas, 481, 530. dextratus, 481, 530. Ammosaunis, 474, 487. . major, 489. Anchisauripus, 470, 471, 476, 477, 479, 486, 492, 543, 544, 545. dananus, 470, 479, 487*, 488, 491, 495, 496. exsertus, 479, 489*, 491, 532. hitchcocki, 479. 488*. minusculus, 479, 488, 490*, 522. parallelus, 479, 490, 491*. tuberatus, 479, 491*, 513, 532. tuberosus, 479, 488*, 522, 532. Anchisaurus, 471, 474, 477, 487. eolurus, 470, 487, 490. polyzelus, 488. Ancyropus, 465, 481, 528. heteroclitus, 481, 529. jacksonianus, 529. Anisichnus, 482. gracilior, 484. gracilis, 484. Anisopus, 482. deiveyanus, 483. gracilior, 484. gracilis, 484. Anonjoepiis, 466, 470, 471, 473, 477, 479, 490, 500, 505, 506, 508, 520, 544, 545. cra.ssu,s, 479, 503*, 540, 545. cuneatus, 479, 504. curvatus, 474, 479, 502, 503*. gracillimus, 479, 504. intermedius, 470, 477, 479, 501*, .502*, 503, 505, 507, 520. isodactylus, 479, 505*. major, 472, 474, 506, 507. minimus, 479, 503, .504*. .527, 528, 545. minor, .500. scambus, 477, 479, 500*, 501, 502. .528. Aaticheiropus. 540. hamatus. 540, 541. pilulatus, 540. Antipus, 481, 536. bifidu.s, 481, 536. flexiloquus, 481, 536. Apatichnus, 479, 485, 493, 499. 508, 509. bellus, 485. circumagens, 479, 508 *, 509. holyokensis, 501, .502. minus, 480, 509*. Arachnichnus, 481. 538. delii.scen.s, 481, 539. Argoides, 465, 480, 518. isodactyletus, 480, 518. macrodactylotus, 480. 519. minimus, 518. redfieldianus, 480, 517, 519. robustus, 480, 519. Argozouin, 466, 518. disparidigitatum, 519. paridigitatiim. 518. redfieidiaHum, 519. Batrachopus, 464, 465. 473. 479. 482, 485, .546. bellus. 479, 485. deweyaiuis, 479, 482, 483. dispar, 479, 483*. gracilior, 479, 484, 485. ' gracilis, 479, 484», 485. Brontozoum, 466, 486, 487, 510, 544. approximattim. 511. divariratum, 512. exsertum, 489. giganteum, 510. gracillimum, 504. isodactyluin, 501. loxonyx, 488. ininusciiluin, 490. sillimaniuin. 487. tuber at inn, 491. validum, 488. Calopus, 465. Cheirotheroides, 479, 485. pilulatus, 479, 485. Chelunoides, 466, 481, 529. iucedens, 481, 529. Chirotlierium, 402, 464, 469, 473, 476, 477, 514, 515. barthi, 462, 471, 47.3, 514, pi. 72*. .storetouensis, 514, pi. 72 *. Chlamydosaurus, 473. Compsognathus, 471, 497, 544. C'omplichnus, 481, 538 obesus, 481, 538. Corvipes, 480, 499, 509. lacertdideus, 480, 510. Cunichnoides, 481, 540. luarsupialoideus, 481, 540. Dimodosaurus, 470*, 471. Dryosaurus, 471. Eubrontes, 465, 471, 480, 486, 487, 492, 499, 507, 510, 544. approximatus, 480, 511*, 512, 532. dananus, 487. divaricatus, 480, 512*, 517, 519. giganteus, 480, 510, 511*, 512, 544. gracillimus, .504. platypus, 480, 507, 512, 51.3*. tuberosus, 488. Eupalamopiis, 481, 531, .532. 556 RiCHARi) SWANN LULL ON dananus, 481, 531. Exocampe, 481, 534. arcta, 481, 534. minima, 481, 534. ornata, 534. Fulicopus, 40.5, 472, 479, 499, 505, 546. yigantens, 507. lyelliaims, 472, 474, 479, 506*, 007*. Gigadipus, 492. caudatus, 492. Gigandipus, 471, 479, 492, 493, 543. caudatus, 479, 492, 493*, 609, 511. minor, 493. Giyantitherium, 466, 492. caudaium, 492. minus, 509. Grallator, 406, 472, 473, 474, 476, 479, 491, 494,496, 521, 544. cuneatas, 479, 495, 496*, 505. cur.sorius, 479, 494*, 495*. formosas, 479, 496, 497*. gracilis, 479, 494, 496, 498, 517, 544. graciUimus, 504. parallelus, 490. tenuis, 479, 495*. Hallopus, 472. Harpedactyliis, 465, 527. concameratus, 516. crassus, 527, 528. gracilior, 528. gracilis, 527. rectus, 518. tenuissimus, 527. Helcura, 481, 530. anguinea, 481, 530. caudata, 531. littoralis, 481, 531. surgens, 481, 531. Hoplichnus, 541. equus, 541. poledras, 541. quadrupedans, 541. Hyphepus, 479, 493. fieldi, 479, 493. Hypsilopliodon, 471, 499, 507, 545. Iguanodon, 470. Isocampe, 481, 537. strata, 481, 537. Kadaliosaurus, 546. Lagunculapes, 480. 525. latus, 480, 525. Leptonyx, 498. lateralis, 498. Macropterna, 532. divaricans, 532. gracilipes, 533. recta, 632. rhynchosauroidea, 533. vulgaris, 533. Megadactylus, 488. Mesonyx, 477. Ornithomimus, 472, 544. Ornithopus, 460, 522. adamsanus, 524. gallinaceus, 522. gracilior, 523. loripes, 525. Orthodactylus, 481, 535. floriferus, 481, 535. introvergens, 481, 535. linearis, 481, 536. Otis, 473. Otozonm, 406, 468, 472, 473, 475, 480, 499, 513, 514, 515, 545. caudatuin, 514. moodii, 472, 480, 496, 511, 513, 514, pi. 72 *. parvum, 480, 515. Palamopus, 465, 481, 531, 532. anomahts, 481, 532. clarki, 631. dananus, 531. divaricans, 481, 532. gracilipes, 533. rogersianus, 481, 533. Phalaropns, 470. hyperboreus, 470. Platypterna, 40)5, 480, 515. concamerata, 480, 516, 518. dean i ana, 480, 516. deanianus, 616. delicatula, 480, 517. digitigrada, 480, 516. gracillima, 616, 617. macrddactylotus, 519. recta, 480, 518. tenuis, 480, 517, 618. varica, 516. Pleclropterna, 466, 619, 520. angusta, 620. elegans, 520. gracilis, 628. lineans, 628. minitans, 601, 520. Plectropus, 465, 519. Flesiornis, 466, 476, 480, 521, 639. aequalipes, 618. giganteus, 480, 522. mirabilis, 480, 522. pilulatus, 480, 521. quadrupes, 501. Polemarclius, 465. 480, 520. gigas, 480, 520. Ptilichnus, 466. Rhea, 470. Sarcorhamphus, 644. gryphus, 544. Sauropus, 465, 501. barrattii, 601. Selenichnus, 476, 479, 498. brevisculus, 479, 499. falcatus, 479, 498, 499. Shepardia, 478, 481, 538. palmipes, 481, 538. Sillimanius, 466, 480, 522, 623, 532. adamsanus, 524. gracilior, 480, 523. rogersianus, 633. tetradactylus, 480, 516, 522, 523. Stenodactylus, 637. curvatus, 537. St«nonyx, 479, 494, 498. lateralis, 479, 498. Steropezoum, 623. elegans, 523. elegantius, 623. ingens, 624. Steropoides, 466, 480, 523. elegans, 489, 523. elegantior, 523, 524. infelix, 480, 524. ingens, 480, 524. loripes, 480, 525. uncus, 480, 525. Sustenodactylus, 481, 536, 537. FOSSIL FOOTriMXTS OF TIIK .1 L'lJA-TKIAS. 557 curvatu.s, 481, 537. Tarsodactylus, 480, 526. caudatus, 480, 527. expansus, 480, 527. Tar.soplectru. DwiGHT. Anatomy of Chimpamzee. itttiOTvfit ^PinTltii CO eO; Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate S. DwiGHT, Anatomy of Chimpanzee. MttiOJyfF pn'rTina co aosTon- Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 9. r.asc.f.S. ! s.sv'b.c.a s.o.i. s.oc.ob. 4 s.o.f. r.asc.f.S- s.pc. I . S.subc p. DwiGHT, Anatomy of Chimpanzee. MeuaftPt PPiHTinC CO BOSTOn. Mi-JMuiKb COM. ---'-'^- Nat. Hist. Vol. 5. Plate 10. S-pCS.' .-^^ !E- fpo.ext. s.i. F- s.c.m. f.c. f.coll. DwiGHT. Anatomy of Chimpanzee. Mtl'OftCl Pftifrtni- CO OOsTOn- in 0 ii < o o CO o cq ^ o J ^ (in O o m CO a; I CD Si <; o IT) o en o PQ m ^ ^ CO O w H Pi •^ i5*5 I u o o m CO S o a CO o in O m \n o W CO K o S 'v'^aaar *■■•■■* "^"-ligaTiirf? M g § ■z Memoirs Bost. Soc. Nat. Hist. Vol. 5 Plate 16. Jackson, Localized Stages. Memoirs s BosT. Soc. Nat. Hist. Vol. 5. 1'late 17. Jackson, Localized Stages. Memoirs Bost. Soc. Nat. Hist. Vol. 5, Plate 18. Jacksos, Localized Stages. Memoir s BosT. Soc. Nat. Hist. Vol. 5. Plate 19. Jackson, Localized Stages. Memoirs Bust. Soc. Nat. Hist. Vol. 5. Plate 20. Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 21. Jacksox, Localized Stages. Memoirs Bost. Soc. Xat. Hist. Vox,. 5. Plate .TAf'Kstix, LocAi.izKii Stages. 3IE.M0IES BosT. Soc Xat. Hist. Vol. 5. Plate 23. Jackson, Localiz?:i) Stages. Memoirs Bost. Soc. Nat. Mist. Vol. 5. l^.ATE 24. Jackson, Localized Stac; 116 1«£4 ES. Mnitrtiits Bust. 8oc. Nat. Hist. Yol. 5. Plate 25. II 10 ^ 8 7 6 S ^ IZ II 10 (f g »M09 8 7 6 5 4 120 /M098 7 6 5 -^ 3 2. 122 119 ' iilo5^3 2. ' 124 a 126 CL Jackson, Localized Stages. Memoirs Bost. Soc. Nat. Hist. Vol. 5 Plate 26. /'' ii. I 6 . -I i, ii JA i.CJ.del H ki^ LJ 7. ?rrr^C^^Vv jik^X: Jeffrey, EouiSETUM. B Meisei IiIIlBosIw. iMOlRE KAi'. Hi.^: PL..rE 2' XM:'mt-VJ^::^\ Jeffrey, Equisetum, HsUotyae Co, Boston Memoirs, Bost. Soc. Nat. Hist Vol5. Plate 28. fM Mi ;■■''•■ '• M' -i ■i* r ' ' ■i 1 i ■' ' 1 .' '■ i ■' -il 'r m '■■^ilfeissiii&pt»'^*'" A t^ 4 cfv^^"^ .>^.t;.. -■1 V Jeffrey. Equisetum. HelioTTPc Co,Bosioa Memoirs, Bost. SoaNAr. Hist Vol 5. Plate 29. ,3^^^- ' Jeffrey, Equisetum. HelictjTje Co, Boston. Memoirs . Bost. Soc. Nat. Hist Vol.5. i-LATE ^■•■fp- ^-' .^>.. r-- ■. i [ ■■^ •*•-.* ., ..^^ 2-. i^.:^^ Fiq Jeffrey, Equisetum Heliotype Cc, Boston Memoirs Bost Soc. Nat. Hist. Vol, 5 Plate 31. RJ^'H del. BlIiELOW, C'aSSIDI'KA XAMA(HAXA. Memoirs Bost. Soc, Nat. Hist. vol. 5. rht Plate 32. HPB dc! I>IGELO\V, ('.\SSI()1>1:A XA^^.\l•II.\NA. Memoirs Bost. Soc. Nat Hist. Vol. 5. Plate 33. BlGELUW, C'.\SSilll'K\ XAMAOIIANA. Me: Plate 34 33. Th wjpS '^'.Ni ,x=--" ,,!;-.: BiGELow, Cassiopea xamachana. Memoirs Bost. Soc. Nat. Hist. Vol. 5. ect cd Plate 35. end 38 40 41 B.BB.del. D 39 43 37 cd BiGELOw, Cassiopea xamachana. Memoirs Bost. Soc Nat Hist Vol 5. Plate 36, 45 RP-- ■^ ,-i:at°-''^^''^ 46 47 ^V=jB a^fi BiGELOW, CaS.SIOPEA X.\ M Aril A NA. Memoirs Bost. Soc. Nat Hist Vol. 5. Plate 37. — Sep JiRB. del. BiGELow, Cassiopea XAMACHAXA. Memoirs Bost. Soc, Nat, Hist. Vol. 5. Plate 38. -el HPB del BiGELow, Cassiopea xamachana. Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 39. viy 5)C / %- n "1 PN ^- ^ yj> Jt^» ■^^ Ol ''-/ //- ^ 3 Morse del B Meisel.ijih Bosicn OH Living Memoirs Bost. Soc. Nat, Hist. Vol. 5 Plate 40. E 3 Morse, del B.Meise! inh Bosior Morse on Living 3rach:opcda Memoirs Bost. Soc. Nat Hist. Vol, 5. Plate 41. E S Morse del Morse on Living Brachiopoda 1 Meisel.Inh Boston Memoirs Bost. Soc. Nat. Hist. Vol. 5, Plate 42. II ^ '1 16 li y r f / '^' V //- E S Morse del i Meisei.iith. Boston Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 43. o.h.s. E S Morse del Morse on Lt/ing Brachiopoda S Meisel lith Bosioit Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 44 h.p " •'1' ] I ^^/«?^;^,r I Meisel.luh Bosion Morse oh Lraing Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5, PL.A.TE 43. ES.Morse del B Meise] lith BcswrL Morse on Living Brachiopoda Memoirs Bosr Soc. Nat Hist. Vol 5. Plate 46. E S Morse del > Meisel, lilK Boston Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 47 ..ge E.S. Morse, del B Meisel liih. Boston Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 48. E S Morse, del B Meisel. iiih Bos Morse on Living Brachiopo DA Memoirs Bost. Soc. Nat Hist. Vol. 5 Plate 49 E S Morse del B Mei£el.litfi.Bosior Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 50. ~ 1 urns E 3 Morse del B Meisel.lnh Boston Morse om Living Brachiopoda Memoirs Host. Soc. Nat. Hist. Vol. 5. Plate 51. & f C w j-i 1.9'- 14 15 [lij no AV E S Morse, del Morse on Living Brachiopoda B Meisei.btK, Boston Memoirs Bost. Spc. Nat. Hist. Vol. 5. Plate 52 i/f'rfb^^^ 1 ; „ i ! I) l_kp -7 ■•■■s.m oh 'I' ■■" '^.a. *.., ■MmM y-"- f'O , (f.pa '/ II ES Morse, del Morse on Living Brachiopoda B Meisel.blH Boston Memoirs Bost. Sog. Nat. Hist. Vol. 5. Plate 55 E S.Morse, del B Meisel. Lith. Boston Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol, 5. m 0 ^ £?" .%%%-.^0§?^ ■^^^ fi la iif- rr 10 E S Morse del S Meisel, lith Boston Morse on Living Brachiopoda Memoirs Bcst. Soc. Nat. Hist. Vol. 5. Plate 56. E S Morse del Morse on Living Brachiopoda Meisei.hih. Boston Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 56. f^W ^:ii£\ I E 3 Morse del, S-Meiseilith Boston MoRS£ ON Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 57 // iS^"% i-P sto \« o o o o \ 14 E S Morse del \ Meisel litK Boston Morse on Lf/ing Brachiopoda Memoirs Bost. Soc. Nat Hist. Vol. 5. Plate 58 E S Morse del Morse on Living Brachiopoda B Meisel.ltth Bosi Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 59. 91' gen CO /etc Tfb nh 5 ^* «■ /« I. I.i E S Morse, del B Meisel hlh Boston "Morse on Living Brachiopoda Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 60. /^ ' ^^,<4^ -spi li slo "'J ES Morse del B Meisel hih Bosion Morse on Living Brachiopoda Memoirs Bost. Soc. Nat Hist. Vol. 5. Plate 6 1 R S Morse del Morse on Living Srachiopoda B Meisel.Iiih Bosior Memoirs Bost. 3oc Nat, Hist Vol. 5. Plate 62 ^ f lb II- II Milili-r, .III Wilder, Skeletal Sys.-em of Necti^rus \ r^ \ frabJ=J'i'OOr of. olfactory f OS / PMX d' #.f^fi/. '% r CafiS.o!-. h^ fii. in.t.nas. # s 'SM. rfT: I \ '' PMX 'fi % ^w- ; 'PT^ isth'. Fer PPT .^ f^:. P, V "0. EKO T'.r. EXO -^ \i L. 1 \. - PO V V: »: .--'*: ' po PQ UP T J^lyni. a.b-0. Memoirs Bost. Sec Nat. Hist. Vol' Plate 64. > CS".; 5>i V- V( ^ A PH / MEMOrRS BOST. SOC.NAT.H'i3T.VOL.5. Plate 6i fy 1 •'S ¥ ® ■ r a "^^*^ : 8 I'' w > U4V9AU0 ^t g )U fe^~ ■'^^. r ^. H.h iVil-Jet.j-l. iLDER.iiKELET.M:, System ofKecturus. TrivlOlRS BOST SC'- S --,..! „^ X .t: 1=^ 'i^T a. :1::Sa> ^d*** o ^ KELETAL System ofNf. McMoihS BosT Soc Nat. Hist. VoL.5. ft. o ^::?^ a. % •^ \ ^%^^.v ^ 3 a. .1 H H « l.-ie-.d.rl. Wii, iTAX, System ofNkct'.iri Memoirs Bost, SocNAr.HisTVoL5. Plate 65 >^ N Jeffrey on Sf.quoia Memoirs Bost. SocNat Hist. Vol.5. Plate 69 Jeffrey on Sequoia Memoirs Bo.st^ Soc.Nat.Hist. Vol.5. YhA.TZ 70 jEFraEv ON Sequoia Memoirs Bost. Soc.Nat.Hist.VolS, FlATE Zl Jeffrey on Sequoia Hehotype C-x^Boc^ly Memoirs Bost. Soc. Nat. Hist. Vol. 5. Plate 72. Lull on Fossil Footprints. sAfmfi' illllliill >;>%^' :. ". -\\?. nm..