4 ieas,, Me Mae htt en She ay : BIRR oo og ieee $2 La ft g Fy ae Vey : x AEs oe Se en 4 “ate EDN ACA ay ae alg NUE 2 ahs Stes ne. even ee Npuy eeae z SSR de Fyn, aA (. 2 Vio! ares ened Ns) Trak : et Hs ; UAV wh Oni i) WA ' nN ie a a su Nei Ont i 1 tn iH SHCTION II. ZOOLOGY. Cll aoe aU. A ote, A MONOGRAPH OF THE PHYLLOPOD CRUSTACEA OF NORTH AMERICA, WITH REMARKS ON THE ORDER PHYLLOCARIDA. By A. 8. PACKARD, JR. PLATES I—X XXVIII. CONTENTS. I.—Classification of living species. ViI.—Relaiion to their environment; II.—Geological succession. habits. III1.—Geographical distribution. VII.—Relations of the Phyllocarida (Ne- IV.—External and internal anatomy. balia) to the Phylopoda. V.—Development and metamorphoses. VIII.—Bibliography. The Phyllopods constitute a division or suborder of the Branchiopoda, an order of Neocaridous Crustacea, intermediate between the Hnto- mostraca (represented by the Copepoda and parasitic forms or fish-lice) and the Malacostracous Crustacea (Tetradecapoda and Decapoda). They inhabit fresh water alone, in a few cases brackish water or strong brine, but none dwell in the sea. The Phyllopod Crustacea are especially characteristic of the western plains of our Territories, where the most striking and typical forms abound, one entire family (Apodide) not occurring east of the western edge of the Mississippi Valley, while the most bizarre member of the entire group, the Thamnocephalus, lives in pools on the plains of Kansas. These Crustacea are of singular beauty and interest in themselves. The outlines of the Branchipodide are interesting, and their movements while swimming on their backs are singularly graceful. Moreover, when we consider the habits of all the Phyllopods; their singular means of adaptation to great changes in their environment; the great vitality of the species; when we take into account their weak and delicate indi- vidual organization, and when we note their interesting metamorphoses and many points in their structure, we are forced to conclude that the Phyllopods are the most interesting of all the Crustacea. The materials for thismonographic account of a most interesting group of Crustacea have been accumulating for over ten years. My collection has consisted of specimens obtained by the various gov- ernment surveys and sent to the Smithsonian Institution, and received from the late Dr. Stimpson, secretary of the Chicago Academy of Sci- ence, shortly before the fire which destroyed the museum of the acad- emy. A large and very valuable collection was made for me by Dr. L. Watson, of Ellis, Kans., while a very valuable collection from Fort Wallace, Kansas, has been kindly loaned me by Prof. Joshua Lindahl, of Augustana College, Rock Island, Ill. Iam also indebted to the Pea- body Academy of Science, Salem ; the Museum of Comparative Zoology at Cambridge, for the loan of specimens, as well as to the Museum of Yale College; and to Dr. C. F. Gissler, Mr. W. P. Seal, Mr. 8. A. Forbes, 295 296 GEOLOGICAL SURVEY OF THE TERRITORIES. Prof. A. E. Verrill, Mr. Edward Burgess, Dr. E. Coues; acknowledg- ments of whose valuable aid are made in their appropnate places. In the following pages I have touched upon some points in the inter- nal anatomy of these interesting Crustacea, and only regret that want of time has prevented me from entering more into detail. For a num- ber of microscopic slides of Branchipus, Thamnocephalus, Estheria, &e., I am much indebted to the friendly aid and skillof Norman N. Mason, esq., of Providence, R. I. I desire also to express my thanks to Prof. F. V. Hayden, for the kind interest which he has taken in this work, and for the liberal number of plates with which the essay has been illustrated. The chapter on the development of the young of Apus lucasanus and Streptocephalus texanus has been contributed by Dr. C. F. Gissler, of Brooklyn, N. Y., who made the drawings which illustrate the text, and also those composing Plates XXXIV and XXXV. A number of the drawings of the entire animal of the species of Apus and Lepidurus, &e., were made by Mr. J. H. Emerton; some anatomical drawings in the plates were prepared by Mr. J.S. Kingley, while I am under obliga- tions to Mr. Edward Burgess for the masterly manner in which he has executed the difficult sketches of the animals of Limnetis brevifrons, Estheria of several species, Eulimnadia, and Branchipus vernalis. I. CLASSIFICATION OF THE LIVING PHYLLOPODA. HISTORY OF THE SUBORDER PHYLLOPODA. The history of this groupis an interesting one. Originally mentioned in 1785, by O. F. Miiller, in his ““Hntomostraca seu Insecta testacea,” the Entomostraca were first defined in 1806, by Latreille, in his Genera Crus- taceorum, &e. Under Legio prima, Entomostraca, the Phyllopoda con- stituted the third order, the sole representative of this order being Apus, while the genus Branchiopoda (Branchipus of Schoeffer) forms part of a sixth order, Cephalota. The other genera of Phyllopods were not then known. In 1820, Brongniart proposed the genus Limnadia for Hermann’s © Daphnia gigas (1804). Meanwhile in 1817, in the first edition of Cuvier’s Régne Animal, the order Branchiopoda was proposed by Latreille, while the classification of this order was further amended and improved in the second edition of this work (1829). In this edition the Phyllopoda constitute the second suborder of the Branchiopoda, and now the Phyllopods comprise the genera Limnadia, Branchipus, Artemia, and Apus. . In 1837, Straus-Durekheim described the genus Hstheria, of which Cyzicus of Audouin (1837) and Isaura Joly (1842) are synonyms. The genus Limnetis was described by Lovén in 1845. In 1840, Milne-Edwards, in his Histoire Naturelle des Crustaces, es- tablished the Legion Branchiopodes, equivalent to the Entomostraces. Under the Branchiopoda he regards the Phyllopoda as forming an order, and they are succeeded by the Cladocera, while the Legion of Hntomo- straca comprises the Ostracoda and Oopepoda. In 1853, Prof. J. D. Dana, in the Crustacea of the United States Ex- ploriung Expedition, regarded the Phyllopoda as constituting the second Legion of his first order (Gnathostomata) of Kntomostraca. In 1863, Gerstaecker regarded the Phyllopoda as forming a family of the order Branchiopoda, the Trilobita, Cladocera, and Ostracoda, forming the remaining families. Claus, in 1868 (Grundziige der Zoologie), divided PACKARD.] PHYLLOPODS OF NORTH AMERICA. 29K his order Phyllopoda into two suborders, Cladocera and Branchiopoda. Gerstaecker in Bronn’s Classen und Ordnungen Arthropoden, 1866-79, adopts the order Branchiopoda, and divides it into three suborders, Os- tracodea, Branchiopoda genuina, comprising the Cladocera, Phyllopoda of other authors, and the Branchiura (Argulus, &c.). In 1879 the writer, in his “‘ Zoology for Colleges,” adopted the order Branchiopoda, with three suborders, viz, Ostracoda, Cladocera, and Phyl- lopoda. Suborder PHYLLOPODA. In this group the body is usually (the Branchipodide excepted) in part covered by a large carapace (the mandibular segment greatly de- veloped tergally), which is in the lower forms (Limnadiacea) bent down, forming two valves, connected by a true hinge, and opening and shutting by an adductor muscle, so that the shell resembles that of a bivalve molluse, such as the fresh-water Oyclas and Pisidium. They have two pairs of antenne, a pair of mandibles, and two pairs of maxille, and in Apodide a pair of maxillipedes. The name of the group, Phyllopoda, is applied to them on account of the feet, which are broad and leat-like, with a series of six primary inner lobes or endites and two exites, the latter forming a gill and accessory gill or flabellum. Theabdomenis not clearly . differentiated from the thorax, and the abdominal feet are not different in shape from the thoracic appendages. The number of body-segments varies more than in any other group of genuine Crustacea, there being seventeen in Limnetis and sixty-nine in Apus, or over three times as many as in the lobster or Decapods in general; the segments are thus often irrelatively repeated, a sign of inferiority. The eyes are either sessile and united into a single mass, or, in the highest family (Branchit- podide), they become stalked, thus anticipating the stalked eyes of the Decapoda. The telson is usually large and spiny, bearing in all the genera a pair of caudal appendages probably homologous with the limbs. All the members of the giborder hatch from the egg in the Nauplius form, like that of the Copepod Crustacea, with some differences, all having three pairs of appendages corresponding to the two pairs of antenne and mandibles of the adult. The species for the most part live in pools of fresh water liable to dry up in summer; those of Artemia live in brine pools and lakes. The eggs, after being fertilized and borne about for a time under the shell or in egg-sacs, are finally suffered to drop to the bottom of the pond; here they lie after the water of the pond has evaporated, the eggs re- mmaining in tae dry mud until, the ponds having been refilled by the autumn rains, the young hatch out and the cycle of life begins anew. Family I. LIMNADIADA® Baird. Limnadiade Baird, Proc. Zool. Soc. London, XVII, 86, 1849; Ann. & Mag. Nat. Hist. 2d Ser. XIV, 229, 1854. Estheriadw Packard, Hayden’s U. 8S. Geol. Surv. Ter., for 1873, 618. 1874. Body inclosed in a bivalved shell; head usually with a large ros- trum; eyes compressed, small, sessile, closely contiguous or united. 1st antenne minute, 3-jointed or multiarticulate, the segments not being well marked; 2d antenne large, with two flagella, each consisting of from 9 to 20 joints. A pair of mandibles; one or two pairs of maxille ; 10 to 27 pairs of swimming phyllopod feet, each witb six lobular endites, and a gill and flabellum divided into two divisions, the upper in the fe- 298 GEOLOGICAL SURVEY OF THE TERRITORIES. male keeping the eggs in place. 1st (Limnetis), or usually the 1st and 2d, pair of feet in the male provided with u hand; the 4th, 5th, and 6th endites modified to form a claw, finger, and thumb-like clasping organs. Posterior segments each bearing a pair of spines; the telson large, com- pressed, often spined, and bearing a pair of eb appendages. Larve nauplius- shaped. Subfamily LIMNETIN AE Packard. Shell nearly spherical, with no lines of growth; rostrum very large and broad at the end, mucronate in the females, broad and truncate in the males; 10-12 pairs of feet ; in the males only the Ist pair provided with a hand; terminal segments of the body not spined; telson undeveloped. But a single genus, Limnetis. Genus LIMNETIS Lovén. Limnetis Lovén, Kongl. Vet. Akad. Handlingar, Tab. IV, 203, 1845; Ofversigt Vet. Akad. Forhandl. 57, 1846; Wiegmanw’s Archiv, II, 203, 1847. Hedessa Lievin, Neueste Schrift. der naturf. Gesellsch. in Danzig, IV, Heft II, 4. Tab., I, II. Hedessa Siebold, Neueste Preuss. Provincialbl. VII (XLI), Heft 3, 198, 1849. Carapace bivalved, nearly spherical, oval, smooth; polished fine pune- ture-like marks in the parenchyma of the shell, giving it the appearance of being finely punctured ; no beaks or umbones. Head large, the fiont bearing the eyes enormous, and produced into a very large rostrum, either truncated in ? and either mucronated or truncated in ¢ in front. Eyes small, sometimes separate. First antenne minute, slightly el- bowed, with indications of three joints; second antenne with scape or base rather short; the flagella rather short, composed of from 15 to 21 joints, with remarkably long sete. From }l to 12 pairs of feet; in the males the anterior pair converted into a complicated hand; the end of the abdomen blunt, simple, with no spines. The species of this genus are readily recognized by the spherical small, smooth shell, with no lines of growth, entirely inclosing the animal; by the enormous head, the large broad rostrum; the few feet, there being but one pair of hands in the males, instead of two, as in . Lstheria, and by the simple unarmed telson. The antenne are shorter and thicker than in Hstheria. They are sometimes mistaken by shell collectors for specimens of Cyclas or Pisidium. They swim on their backs, with the shell a little open, in a graceful but not very rapid man- ner compared, with the Ostracoda. Synopsis of the species. Shell subspherical, small, front of head of male narrow; second antenne 16- jointed ; flabellum very large....-- DL gouldii. Shell large, suboval; front of male broad and square ; second antenne 14 and 17 jointed; flabellum remark- ably marrow) 2.0))2) [2S eT ara eree en ees LL. mucronatus. Shell large, suboval; front broader than in any other spe- cies except gracilicor nis; antennee 20-jointed; gill very large, flabelium short and broad.......-..---.------ L. brevifrons. Shell small, subspherical; front very broad; antenne long, 20 jointed OS Se) LUCAS: 1S a So SD Pe EE Ce LL. gracilicornis. PACKARD. ] PHYLLOPODS OF NORTH AMERICA. 299 LIMNETIS GOULDII Baird. Plates II, Figs. 1-6; XXIX, Fig. 9. Limnetis gouldii Baird, Annals and Mag. Nat. Hist., 3d ser., vol. x, 393, 1862. Shell smooth, spherical, quite round, not often oval as in the two succeeding species, and of a uniformly ‘smaller size. Ist antenne very slender, not so broad at the end as in L. brevifrons. 2d antenne with the stem longer and slenderer than in the two following species; the upper flagellum 16, the lower 16- jointed, with longer sete than in the other species. First leg of female with a very large, long, and broad flabellum (br’), the posterior division (br’’) very long and slen- der, closely resembling the 6th en- dite, but considerably longer; the gill rather small. The coxal lobe (1st endite) rather broad and not ar so long as in the two other species; y/ fh)" the hand is much slenderer, and the claw (6th endite) is longer and Fic. 1. oF gouldti, enlarged. Burgess del. ist slenderer than in L. mucronatus ; antenne not drawn. in the male the coxal lobe is considerably smaller and more triangular and acute than in the two other species; the comb, or 4th endite (/*) is armed on the edge with an inner row of small and a marginal row of much larger digitate setiferous processes; the finger (/°).is of moderate size, and the claw-like 6th endite is long and slender; the flabellum (br ) is about twice the size of the gill; and its posterior process (br/’) is long, narrow, extending only a little beyond the base of the 6th endite. The front in the male (Fig. 3 d, in text) is truncated, but contracts below the eyes more than in the other species; while the carina on the front of the head is unusually high. In the female the rostrum ends in a sharp point, with lateral acute angles much as in sharply mucronate specimens of L. mucronatus. Length of the shell, 3™™; breadth, 22™™. The species was first discovered in “fresh water at St. Ann’s, twenty miles from Montreal, Canada.” Collected by Charles Gould, esq., June, 1857 (Brit. Mus., W. Baird). The young received from Hanover, N. H. Near Boston, Mass. (Edward Burgess); near Providence, R. L., in great abundance in a pond which dried up in midsummer, occurring during May, and for at least a month after Branchipus vernalis had disappeared from the pond (A. 8S. Packard, jr., and H. C. Bumpus); abundant in a pond at Glendale, Long Island, in March and April (Dr. C. F. Gissler) ; Normal, Ill. (S. A. Forbes); Rock Island, Il. (W. H. Pratt, Davenport Academy). This is our most abundant species, and appears to range over New England, Canada, westward to the Mississippi River at Rock Island, fll. It is distinguished from the two other species by the more spher- ical shell, its smaller size, the rather narrow, contracted front of the male, and by the differences in the antenne and legs indicated in Plate I. We have kept these beautiful little phyllopods in confinement from early in May until the middle of July, with few changes of water; 300 GEOLOGICAL SURVEY OF THE TERRITORIES. they appear to be very hardy compared with the Branchipodide. The animals are pale flesh-colored, with black eyes, and are tolerably rapid in their movements, Swimming often on their backs and rapidly gathering the vegetation at the surface with their antennz and either their coxal lobes or jaws. The eggs are carried upon the back under the shell, and are found in the spring. We have received numbers of the cast shells of the larva or nauplius from a correspondent at Hanover, N. H. The carapace bears a close resemblance to that of the nauplius of the European L. brachyura, hay- ing the lateral front spines and two small caudal spines. LIMNETIS MUCRONATUS Packard. Plate I, figs. 1-6. (In fig. 1 the 1st antennz are not represented by the artist.) Limnetis mucronatus Pack.., Auueieear Naturalist, ix, 312, 1875. Bulletin Haydon s U.S. Geological and Geog. Survey, ili, No. 1, ae 1877. Male.—Carapace much flattened, oval-triangular, the dorsal edge of the valve but slightly curved, the posterior end well rounded, while the front end is but slightly curved. Head in front truncate, much as in the males of L. gouldii and gracilicornis, the end being broad and square. Hand large, a little longer than broad, with the claw large, and as long as the hand is broad; the lower edge of the hand (or 4th endite) armed much as in LZ. gouldii. There are twelve pairs of limbs, the twelfth ending in a pair of large, strong, recurved hooks. The end of the terminal segment on its ventral side is rather more pro- duced, and with a more conspicuous spine than in the female. Two males occurred among forty-four females. The length of carapace, 4™™; breadth, 3.2™™. Female. — Car apace scarcely distinguishable from that of L. gracilicornis in outline, though it varies slightly in form, some being quite round and regular, others slightly ovate, and some quite flat and triangular. Muscular impression as in Z. gracilicornis, but the muscular impression is much broader and proportionately shorter than in L. gracilicornis, where the front of the head is suddenly truncate, and wider at the extremity than behind in gouldit; while in gracilicornis it is also trun- cate, but does not contract so much in front of the eyes, the narrowest point be ing between the eyes and the end of the front. In the present species, however, the front is very much produced into a long, acute, mucronate point, with two teeth on each side, the middle tooth vary- ing much in length. The carina is very Fic. 2.—lymnetis mucronatus, male; high and sharp (see a in Fig. 3 in text). claw; both enlarged. 1st antennw’ py! od antenn with the second joint half as raya. slimentonidel- long as the basal; the four succeeding joints very close, and together not as long as the succeeding seventh joint, from which arises “the flagellum, the upper branch of which is 14-15-jointed, the lower one 17 jointed, with ciliated hairs about as long as in ZL. mucronatus, the longest ones as long as the entire antenna. Twelve pairs of feet. The feet have a very long and slender flabellum, the gill being either in the first pair short and rounded at the end, or in the second and sue- ceeding ones long and pyriform, being about the same shape and size PACKARD. ] PHYLLOPODS OF NORTH AMERICA. 301 as in LD. gouldit; the filiform lower end (PI. I, Fig. 4, bv.) is much shorter than in L. gouldii, and endites 4—6 are also much shorter; while the coxal lobe is large and very long. End of the body blunt, squarely docked, the point blunter than in L. gouldii, and ending in a slender spine. Two dorsal terminal filaments, much as in LD. gouldit. Length of carapace, or shell, 4™™; breadth, 3™™. Forty-four females, nearly all with eggs, occurred with Lepidurus couesti, in pools on the west bank of Frenchinan’s River, Montana, 49° N. (Dr. Coues.) It also occurred in large numbers associated with Limnetis brevifrons in pools at Ellis, Kans., collected by Dr. L. Watson June 29, 1874. The specimens - were females with eggs, and as a rule were triangular in outline, com- pressed, only one or two of the Montana examples being so much com- pressed. The species is easily recognized by the mucronate, tridentate front, the short, thick hand and claw, by the number of antennal joints, and the long, narrow flabellum, the short endites 4-6, and by the long, stout, jaw-like coxal lobes. LIMNETIS BREVIFRONS Packard. Plate XXVII, figs. 1-3. Timnetis brevifrons Packard. Bulletin of Hayden’s U. 8. Geol. and Geogr. Surv., iii, No. 1, 172, April 9, 1877. Many females. Carapace decidedly triangular in outline, more so than in L. gouldii, while it differs very decidedly in this respect from gracilicornis, and is considerably larger than gracili- cornis or mucronatus, and is flatter than both. Front shorter and broader than usual; less contracted in width at the base of the antenne than usual. The frontal carina is high, especially a little in front of the i Fic. 3.—Front of Fic. 4.—Limnetis brevifrons, female, much enlarged. Burgess del. head of Lymnetis oe eyes. Compared with that of Lymnetis gracilicornis Gioia len ace | LRT b, in text) it 1s much broader, shorter, the WEE d, ¢ keel reaching to the end, which is squarely docked, the end being a flattened triangle; the end of the front reaches to the middle of the antenn, while in L. gracilicornis the end reaches two-thirds of their length. It differs from Z. gouldii (Fig. 302 GEOLOGICAL SURVEY OF THE TERRITORIES. 3, d) in the front being thicker, the truncated end forming, seen from the end, a much less flattened triangle. First antenne much stouter thanin Z. gouldii. Second antenne con- siderably longer than in LZ. gouldit, the terminal joint extending well beyond the end of the front, while in Z. gouldii it does not extend be- yond the front; the upper branch of the flagellum has 20 joints; the lower, 20. (In L. gouldit there are 14 joints in the upper and 12 in the lower branch of the antenne.) In form the antennz resemble those of LZ. gouldii, but the setz are much shorter than in any of the other species. There are 12 pairs of feet. The male has a much smaller hand than in L. gouldii or , I. mucronatus, the claw (Plate XX VII, fig. 3, en®) is Shorter, but the finger (en? should be en*) is much larger than in the foregoing species. The @9 jaw-like coxal lobe is larger than in L. gouldii or L. mucronatus. The gill is enormous, as is also | the flabellum (br'!), the two being of the same irik liad Fo eas bet size and! half as/long a8 j,cicraiat: 5 nent ec ladon orate ly enlarged. Lindahl del. the entire limb, while the Lindahl del. lower division of the flabellum, that next to the hand, is rather broader and larger than in L. gouldit. In the female the upper division of the flabellum (br!) isshort and broad ; the gillis very long; the lower division of the flabellum (Plate XX VII, fig. 2 a) is as in L. mucronatus ; the 4th endite is long and narrow, while the 5th is longer than the 6th. Terminal segment less prominent than in L. mucronatus, while the dorsal edge is less excurved. Average size of most of the specimens: Length, 4™™; breadth, 34™™. Several larger examples were 6™™ long and 5™™ broad. Ellis, Kans., June 28 and 29, Dr. L. Watson, in pools, associated with several other species of Phyllopods. A few eggs were contained in inost of them. This is the largest species known, and is as a rule flat- ter and more triangular than any other species, while the truncate front of the head of the male is shorter and broader than in any other American species yet known. LIMNETIS GRACILICORNIS Packard. Limnetis gracilicornis Packard. Amer. Jour. Se., 3d ser., vol. ii, Aug., 1871. This species differs from L. gouldti in the longer and slenderer 2d an. tenne, the flagella of which are 20-jomted; the keel on the front of the head does not reach to the front edge, while in L. gouldit it does. (Fig. 3, 0.) Shell of the same form, but much larger than in L. gouldii. Length of shell, 4.2"; breadth, 4™™. Waco, Tex., with Hulimnadia texana and Streptocephalus texanus (G. W. Belfrage). I have unfortunately been unable within late years to obtain any specimens for dissection and study. PACKARD.] PHYLLOPODS OF NORTH AMERICA. 303 Subfamily ESTHERIAN di Packard. Carapace or shell obiong, more or less flattened or oval, sometimes subglobose, with distinct lines of growth. From 18 to 27 or 28 pairs of feet; in the males the two anterior pairs of feet with hands; the end of the abdomen with dorsal spines and two pairs of very long, large, curved, terminal spines. Synopsis of the genera. Shell oval, more or less globose, with 18-22 lines of growth, amber-colored; flagella of 2d antennz 11-17 jointed; PeaOeG Ol Ao AILS Ot TCC pcre oie goin) baju as we aus aie ic ote Estheria. Shell large, broad oval, much flattened, subtriangular, with about 18 lines of growth, a haft-organ present. Flagella of 2d antennz 12-13 jointed; 18-22 pairs of feet..-.... Limnadia. Shell narrow-ovate, rather prominent behind the umbones, with 4-5 lines of growth. ==ee eee a basal hook bris- tle, first p lain Fic. 56.—Sete of first maxilla of Eubranchipus. then ciliate (Fig. 55a) and then split. Second bristle-hook appears ( Fig. 55 d) to be triangular or rounded exteriorly, and two-edged and ciliate Fic. 57.—Anterior antenna of pale Eubranchipus mounted in gly- cerine osmic acid prep. From a specimen with three branchipeds budded, 1st of the latter with a single claw. interiorly. The terminal outer branch of the second an- tenna has fifteen long bristles and a terminal shorter one; the inner or posterior branch has three long and one short bristle. This branch is three-jointed; terminal branch is subjointed. First maxilla of adult Hubranchipus is plain, and has thirty-one long, flat, acinaciform bristles or teeth, equally long (Fig. 56.) The second maxilla is composed of a narrow, small, basal piece, with two strong, thick spines, each finely ciliate. 430 GEOLOGICAL SURVEY OF THE TERRITORIES. Mandibulary palpus is four-jointed, bearing seven ciliate bristles, the two basal and the three terminal ones being nearly straight (more so the former); the two middle bristles have a stout base, and are curved inwardly (Fig. 55 c). ch. The first (anterior) (Fig. 57) and second antenne have their basal half, in very young forms, at least, peculiarly ciliate. This is mentioned also by F. Span- genberg, but not figured.- Second antenne.—At the time of sexual differentia- tion the greater part of the bristles and the inner eee teee. Seu Wie branch drop, the basal piece sprouts a few single ciliz ded, Ist of the latter with (NOt in groups), and from the under side at its base asingle claw) : Lower part fhe future first clasper-hook begins to bud, which of abdomen with a chitin- : 5 ous bacillus, ch., entering then becomes corrugate at its tip. An exuberant ie aay ae cell—complex in the basal piece, formation of trans- retreated through the ef- verse and longitudinal muscles, subdivision of the fectionosmicwacid: terminal piece of the antenna near its base, and bud- ding of a small roundish protuberance at the inner side of the middle piece takes place, and the male clasper is nearly developed. If a female specimen, the en- tire antenna re- : mains but with a Ti muscular differ- ae entiation; and at : its inner base, on Fig. 59.—Seta of first maxilla of Streptocephalus texanus. a broad frontal protuberance, a number of hyaline ciliz appear. Some- what later the form of the female clasper slightly changes into one peculiar to this genus (Fig. 61), which is very vari- able in form. At the time when in the male clasper the first hook is budding, the frontal tentacles are already present, but owing to their tendency to coil ven- trally and their small size I did not succeed in closely following their mode of origin (Fig. 60 B). In its early stage the margin is entire, with a con- tinuous row of large marginal cells; plasmatic contents in general intermingled with oil globu- les, and longitudinal muscles transversely striate. I think at a later time the latter will branch lat- erally, since the developed tentacle shows also transverse muscles. The peculiar mammiform excrescences along the margin are attained after several moults. Larve with three branchipeds budded, the first of which, with a single claw, show the develop- ment of the post-abdominal fwrea, as illustrated by Fig. 58. I am of the opinion that the narrow piece running along the end of the body is a sup- Maree port for the embryonic furca, and is not a muscle Bubranehipusy from tite. but a chitinous stick or bacillus, which, after one joint, old antenna; D, longitadi- OF More moults (Fig. 63) is pushed out, and its neta Sree hocks cer ite a mM ent becomes ciliated. But the latter, after F, future inner angle wherefrom more moults, does not become the permanent ID) CRIES at EEN. Jurca, as we should expect, for it is cast off with the other integument, and the typical development of the furca begins (Fig. 62). PACKARD.] DEVELOPMENT OF BRANCHIPODID”®. 431 No internal chitinous support is found until in the adult state, when we again meet with a flat chitinous plate, confined to the furca alone. It is -—-———asse Fic. 61.—Female claspers ; b more peculiar to the pale race. an interesting phenomenon to see that the red normal Hubranchipus has a white and the ale prace a red furca. The transparent, greenish, S Chirocephalus holmani and the whitish Streptocephalus Sant texanus have also a red furca. The red Hubranchi- pus occurs in brownish, clear water, the others in tur- bid, milky water. It may be an assistance in copu- lation, i. e., to make the individuals more visible, or conspicuous, Spangenberg (in op. cit. page 10) makes it more than plausible that the first (anterior) antenn \ N/ y Sa : A % 4 Fic. 63.—Last fe Fic. 64.—Hubranchipus, red 2 larva, 13™™ long; ments of an anwar sides of head fimbriate above. From life. Giss- _ larvaofig~™length. Cam- ler del. Ca caaie ids of Branchipus are homologues of the leg, and I ven- paration. P’, fifth pair ofture to compare the frontal tentqcles in a similar peds; int, cast-off 2 ; integument (by the osmic manner. The following points support this theory: faven, dilidte: Gisdae der, Lirst, they are lateral appendages; second, their marginal appendages, more developed exteriorly, closely agree with the embryonic development of the branchipeds, from a single mammiform process up to two and three of the latter. The frontal appendages are different in nearly every species of branchio- pod crustaceans; they are sometimes on the basal portions of the clasp- ers in the adult, or they are reduced to minute papille. Dybowsky' calls them basal appendages, referring to the base of claspers, while Grube calls them more properly frontal appendages; Fischer calls them cephalic tentacles (Middendorf’s Reisen nach Sibirien, Band II); Verrill calls them lanceolate, ligulate, fleshy processes. ‘Archiv. fiir Naturgeschichte, 1860, Vols. 1 and 2, 26th Jahrgang: Beitrag zur Phyl- lopoden. Fauna der Umgebung Berlins nebst Kurzen Bemerkungen iiber Cancer pal- udosus Miiller von B. von Dybowsky, M. D., page 195, Taf. X. A432 GEOLOGICAL SURVEY OF THE TERRITORIES. VIL—THE ORDER PHYLLOCARIDA AND ITS SYSTEMATIC POSITION. Having studied the Phyllopoda, we may now discuss the relationships of Nebalia and the group which it represents. History of the Phyllocarida.—The genus Nebalia was first established by Leach! in his Zoological Miscellany, vol. 1, p. 99,1514. Nebalia geoffroyi Edwards, was described and the external appendages figured by Milne-Edwards in the Annales des Sciences Naturelles, tome 13, p. 297, 1828, and in the 2d series, tome 3, p. 809. Our Nebalia bipes was originally described under the name of Cancer bipes by Otho Fabricius in his Fauna Groenlandica, 1780. In his Histoire naturelle des Crustacés (1840) Milne-Kdwards places Nebalia in the family Apusidze among the Phyllopoda; at the same time he remarks: “Les Nébalies sont de petits crustacés trés-curieux qui, a raison de leurs yeux pédonculés et de leur carapace, se rapprochent des Podophthalmes, mais qui ne possédent par de branchées proprement dites, et respirent 4 Vaide des membres thoraciques devenus mem- braneux et foliacés. Elles semblent, & plusieurs égards, établir le pas- sage entre les Mysis et les Apus.” In 1850 Baird, in his British Entomostraca, founded the family Nebaliade, regarding Nebalia as a Phyllopod. In 1853, in his great work on Crustacea, Prof. J. D. Dana gave the name Nebaliade to the family, with a diagnosis. He placed the group in his tribe Artemioidea in the Legio Phyllopoda. Nebalia remained, by the general consent of carcinologists, in the Phyllopoda until Metschnikoff, in 1865, published an abstract of his essay on the development of Nebalia geoffroyi, which appeared in full in 1868. Unfortunately, his work was published in Russian, but Fritz Miiller, in his “Viir Darwin,” quotes as follows from Metschnikoff, ‘that Nebalia, during its embryonal life, passes through the Nauplius and zoea stages, which in the Decapoda occur partly (in Penéus) in the free state.” ‘Therefore, I regard Nebalia as a PhyNopodiform Deva- pod.” In 1872, Claus gave an account, with excellent figures, of the external anatomy of Nebalia geoffroyi; and in 1876, in his valuable work on the genealogy of Crustacea, he described the internal anatomy of the same species. In 1875, in his “Atlantic Crustacea from the Challenger Expedition,” Willemoes-Suhm placed the Nebaliade among the Schizopoda. While, however, the thoracic appendages of his Nebalia longipes have very narrow respiratory lobes (exites), yet they can be directly homologized with those of the other species of Nebalia, and in all other characters N. longipes does not differ essentially from the other species of the genus. In 1879, in the American Naturalist for February, 1879, and in our “Zoology” (1879) we proposed the name Phyllocarida for Nebalia and 1¢¢Dr, Leach, in his ‘Naturalist?s Miscellany,’ vol. 1, p. 99, published in 1814, describes it [ Nebalia bipes] more fully than Montagu, and says the species he describes is not uncommon on the southwestern and western coasts of England. As he saw that it constituted a very distinct genus from any previously given by modern writers, he formed the genus Nebalia to receive it, and adds, ‘in a systematic work this genus would hold a very conspicuous and important place, as it is not referable to any family hitherto established.’ In a paper published soon afterwards by him, in vol. xiof the Linnean Transactions, on the Arrangement of the Crustacea, he assigns 1is place amongst the Malacostraca, in the order Macroura; in which he is followed by Lamarck, Bose, and Desmarest, Latreille, Olivier, and Risso; the three latter authors, however, referring the species described to the genus Mysis.” Baird’s British Ento- mostraca, p. 32. 1850. PACKARD.] ANATOMY OF NEBALIA. 433 its fossil allies (see Bibliography), and gave a description of the order and mentioned the types composing it. Nearly a year later, in 1880, Claus, in the last edition of his Zoology, according to Carus’ Yahresbericht, 1880, also suggested that Nebalia represented a distinct order, which he calls Leptostraca. We have not seen the last (fourth) edition of Claus’ Zoology (1882), in which the or- der is noticed. Habits.—The species of Nebalia inhabit the sea at moderate depths. We have dredged WN. bipes on the coast of Labrador in from four to eight fathoms, and on the coast of Puget Sound we collected a sim- ilar species, just below low-water mark, among fucoids. The fol- lowing is taken from Baird’s British Entomostraca: ‘‘Otho Fabricius tells us that it carries its eggs under the thorax during the whole winter; that they begin to hatch in the month of April, and that the young are bornin May. They are very lively, he adds, and adhere to the mother, who appears then to behalf dead. The adult swims in a prone state, using its hinder feet to propel it through the water. They are not very active. Montagu informs us that when moving in the water the superior antennz are in constant motion as well as the abdominal feet, but that the inferior antenne are usually motionless and brought under the body. They are found, according to Leach, on the south- western and western coasts of England, under stones that lie in the mud, amongst the hollows of the rocks; and Mr. McAndrew dredged it from a considerable depth amongst the Shetland Isles.” 1.—THE ANATOMY AND DEVELOPMENT OF NEBALIA. The first published description of the present species was by Kroyer, in his Naturhistorisk Tidskrift (Ser. 2, Bd. 2). It is written in Danish, and not accompanied by any figures. In Nebalia bipes the body is rather slender and somewhat compressed, the anterior half protected by a carapace, beyond the lower edge of which the broad thin phyllopodiform feet do not project. The carapace.—The head and anterior half of the body, including the thorax and four anterior abdominal segments, are covered by the cara- pace, which on the lower edge extends below the ends of the thoracic feet, covers the basal joints of the antennz, and entirely covers the mouth parts. The sides are compressed, and are drawn together over the body by a large but rather weak adductor muscle (Pl. XXX VII, fig. 6), situated a little in front of the middle of the thorax. There is no large highly specialized adductor muscle connecting the two sides of the carapace, nor any well-marked round muscular impression in the cara- pace, such as is characteristic in the Estheriadw; nor is there any hinge, a still more characteristic feature in the bivalved Phylopods. On the contrary, aS seen in Pl. XXXVI, fig. 3, representing the carapace re- moved from the body and flattened out, there are no signs of a median hinge-joint. The nature of the rostrum is one of the diagnostic features of this order. In Nebalia, the rostrum is long and narrow, oval, seen from above, terminating in an obtuse point quite far in advance of the head. It is loosely attached to the sinus in the front of the carapace, and thus forms a long, narrow, tongue-like flap, with a free movement up and down. It is thus seen to be rather a movable appendage of the cara- pace than a solid, immovable continuation of it, as in the Decapoda. Upon removing the carapace and flattening it out, it is seen to be readily comparable with the carapace of Ceratiocaris. 28 434 GEOLOGICAL SURVEY OF THE TERRITORIES. The eyes. —The eyes are mounted upon a stalk, and thus Nebalia may be said to be essentially stalk-eyed. In this respect it is similar to the eye of the Branchipodide on the one hand, or to the eye of the Decapoda on the other. They are inserted just above and slightly in front of the 1st pair of antennz. The cornea is considerably less in extent than the end of the eyestalk itself, and in this respect differs from the eye of Decapods. The antenne.—The two pairs of antenne are large, well developed, and of nearly equal size in the female, but in the male the second pair extend backward beyond the bases of the caudal appendages. In the 1st pair the stem (scape or protopodite) is seen to be composed of fine joints, the Ist, 2d, and 4th the longest, the 3d and Sth short. From the scape arises the flagellum or endopodite, which has 16 well-marked joints, each joint provided externally with numerous sets; and besides, there arises from the 5th joint of the scape or stem a scale-like unjointed appendage, which may be regarded as an exopodite; if so, then the 1st instead of the 2d antenne in the Phyllocarida bear a scale-like exopo- dite; the 2d antenne in Decapoda bearing the exopodite. The outer edge of this exopodite is thickly fringed with numerous long, delicate sete. It thus appears that what corresponds to the setze or protopo- dite of the 1st antennz of Decapods consists of 5 instead of 3 joints. The 1st antenna of Nebalia._may be compared with that of the first stage of the larval lobster (Smith, Pl. XV, fig. 8) at the period when the exopodite is short, scale-like, and single-jointed. The 2d antenne have a 2-jointed stem or scape (protopodite), and a single long many-jointed flagellum or endopodite, the basal joint a large one; no exopodite being present, even in a rudimentary form. The 1st and 2d antennz are thus seen to be quite unlike those of the Malacostraca, and to resemble the Copepods, in that the anterior pair are rather the stouter of the two; but in those Copepods with very long ‘antenne it should be remembered that they are the Ist and not the 2d pair, as in the male Nebalia. It will thus be seen that while the anten- ne of the Phyllocarida are entirely unlike those of the Phyllopoda, they are neither closely homologous with those of the Decapoda (Mysis or Cuma) or the Copepoda. The 2d antenne of the male is said by Claus to be very long, and to resemble those of male Cumacee, but upon a comparison the stem of the antenna is in Cuma quite different in the relative length of the three joints. So also, while, as Claus observes, they are like the antennz of the Amphipoda, this resemblance is quité general; on the whole, how- ever, the antenne of both pair bear a general resemblance to the Mala- costracous type; also, on the other hand, they may also be compared with the more primitive Copepodous type. The mandibles (Pl. XXXVI, fig. 4; fig. 2, md).—These are remarkable from the small size and weak development of the biting edge or mandi- ble itself compared with the palpus. The oval or biting end of the protopodite is small, and armed with comparatively few and weak sete, which shows that the Phyllocarida probably feed on decaying animal and vegetable food, which is easily brushed into the mouth by their slight stiff bristles. The palpus, however, is enormously developed, extending out quite to, if not a little beyond, the edge of the carapace (Fig. 1). It is 3-jointed; the 2d a little longer than the basal, and swollen at the base, while the 3d is somewhat longer but slenderer, and edged with a fringe of close-set, rather stiff sete. Though soimmensely developed as to the palpus, and entirely unlike the mandible of the Phyllopoda, in which only the protopodite is developed, it may be com- PACKARD. ] ANATOMY OF NEBALIA. 435 pared with the mandibles of the Decapoda, especially of Mysis and other Schizopods,! in which a very long three-jointed palpus is developed. But the very long and large mandibular palpus and very weak protopo- dite may be set down as a diagnostic feature of the Phyllocarida. The 1st maxille (Pl. XXXVI, fig. 2, ma'; fig. 5, mx'; 5 a).—These are likewise singular and diagnostic features of this order, as represented by their structure in the Nebaliadew. They consist of a small lobe (Fig. 5 a, cv!) with about 8 stout sete, and a larger lobe (cx’) with the outer edge fringed with long coarse sete, one of which is a large ciliated seta; from this arises, after bending on itself at its base an extremely long and slender muliarticulate process (or endopodite?) which, in the female, is directed upward and backward (Fig. 5 a, en), reaching to the tergum of the basal abdominal segment, and ending in two very long slender sete, while a few other similar sete arise, one from each joint.? In the male of N. geoffroyi, according to Claus, the long setose process is directed forwards and downwards. The 2d maxille (Pl. XXXVI, figs. 2, 5, mx?),—These are entirely unlike those of the first pair, and unlike the Decapodous or Phyllopod type. They consist of a basal portion composed of four thin, delicate, unequal lobes (Fig. 5, ++), edged with long sete, with two sete twice as long as the others arising from the 4th lobe; from this 4-lobed basal joint or coxopodite arise two appendages, the anterior (exopodite, ex), small, 1-jointed; the posterior (endopodite, en), 2-jointed, the end of the second joint carrying above 5 long, spreading, stout, slender sete. This two- jointed appendage Claus considers as representing the stock of a palpus. This pair of maxilla are quite unlike those of Decapods (Mysis, etc.), as well as those of the Phyllopods, and appear to be another diagnostic feature of the order. The absence of any maxillipedes, or of any rudiments of them, either in the adult or in the embryo, is a negative character of a good deal of importance when we regard the affinities of the group to the Decapods, or the zoéa-form of the same order, where two (Macrura) and three (Bra- chyura) pairs of maxillipedes are present, there being three pairs in the adult Decapod. The eight pairs of Phyllopodiform thoracic feet (Plate XX XVII, fig.3).— The maxille are directly succeeded by eight pairs of leaf-like thoracic feet, the maxillipedes not being present. The feet all repeat each other in form, and a description of the 3d or 4th pair will answer for the Ist as well as the last. The leg (Fig. 3, 3d or 4th pair) consists of a broad, thin, six-jointed appendage, the endopodite (en), which is fringed with very long delicate sets, those arising from the terminal joint being cil- iated; while a second series of fine stiff setse arise obliquely from the edge. To the second joint of the endopodite are appended a distal or lower very broad thin gill, not quite twice as long as broad, and which reaches to the end of the endopodite, while situated more exter- nally is a double broad large lobe which corresponds to the exite or fla- bellum of the Phyllopod foot, this flabellum being as long as the entire endopodite, but not quite so broad asthe gill. The distal portion of the flabellum is more pointed than the proximal, and, as will be seen by re- ferring to the figure, is more actively engaged in the process of respira- tion. The figure shows by the dotted lines of parenchymatous matter 1Compare G. O. Sars. Monographi over Mysider, 1870; Pl. I, fig. 8. Claus states that the large palpus is very similar to that of many Amphipoda, but apparently overlooks the still closer resemblance to that of Mysis. 2Claus draws attention to the position of this foot as compared with the 2d max- ille (putzfuss) of the Ostracoda. 436 GEOLOGICAL SURVEY OF THE TERRITORIES. * the course taken by the blood in passing through the gill and accessory gill or fabellum, and that it must also be partly aerated by the jointed endopodite; the entire appendage, therefore, as in those of the Branchi- podide, is concerned in respiration. It will thus be seen that the limb is lamellated, but differs essentially from the Phyllopodous limb in that the endopodite is simple, the axis multiarticulate, but sending off noendopodal lobes from the axites, such as form the characteristic feature of the Phyllopodous foot. From overlooking this important and radical difference from the Phyllopodous foot the earlier observers were led to place Nebalia among the Phyllopods. In comparing the thin, lamellar thoracic foot of Nebalia with the thor- acic foot of any Decapod from Cuma to Mysis, and up through the Ma- crura to the crabs, it will be found impossible to homologize the parts closely, though a general homology is indicated, the endopodite of the Nebalia and the gills corresponding in a general sense to those of the -Decapods, and it is this lack of close homology more than any other which forbids us from regarding the Nebalide as entitled to take rank under the order of Decapoda, or with any of the Malacostraca, But when we compare the thoracic legs of the adult Nebalia with the maxillipedes of the zoéa of the Decapods, then we can detect a slight and interesting resemblance, but the resemblance and homology is not so close as between the thor- acie legs of the Phyllopods and the maxille of the early zoéa. On comparing the broad Jamellate thoracic feet of the adult Nebalia with the rudimentary thoracic feet of the later stages of the zoéa the re- semblance is but slight. Just before the zoéa passes into the adult con- dition the five pairs of thoracic feet of the adult bend out as two-lobed processes; but the resemblance to the leaf-like foot of Nebalia is too re- mote to be of any taxonomic value; and this remote resemblance shows that Nebalia does not belong to the Decapod type. The six pairs of abdominal feet ‘Plate XX XVII, figs. 4, 5).—Turning to the abdominal feet, we find that they are simple, without gills, and entirely different from the leaf-like thoracic appendages, and we have in this differentiation of true abdominal from the thoracic feet a Mal- acostracan character, one quite unlike the differentiation or blending of the two regions in the Phyllopods. The abdomen is nine-jointed, the segments cylindrical and edned with obtuse spines (Pl. XXXVI, fig. 8.) much as in Copepoda. The segment succeeding the 8th thoracic is much larger and extends farther down sternally than the 8th thoracic, and bears a large, stout pair of feet, to which the three following pairs are closely related in form. For example, the 2d pair (PI. XXXVIL, fig. 4) consists of a large, thick, long stem (protopodite) which sends off three appendages, an outer (ex. opodal) stout, blunt appendage, (ex); edged with stout sete externally and more densely on the inner edge with ‘ciliated, delicate setz the mid- dle two-jointed appendage (endopodite, en) is longer and slenderer than the outer, and edged externally with finer sete; a third minute bract-like appendage, Claus Says, acts as a retinaculum (ig. 4, ret.) to connect the two legs of the same pair while the creature is in ‘the act of swim- ming. In their general form the abdominal legs appear to resemble the simple biramous “legs of the Copepoda, but still 1 more closely those of the Amphipoda, in which, as Claus observes, there is a similar retinaculum. (See also Milne- Edwards's Crustaces, Pl. 30, fig. 37.) The 5th and 6th segments of the abdomen bear much smaller, more rudimentary legs. The first pair (Pl. XX XVII, fig. 5) are seen to be two-jointed, the 2d joint long and slender, bearing near the end stout raptorial sete, and on the inner edge slender sete. The 6th pair are PACKARD.] ANATOMY OF NEBALIA. 437 still more rudimentary, one-jointed, and with but few sets, which are stiff and coarse. These resemble the simple, unbranched 5th and last pair of abdominal feet in Copepoda (Calanus ¢ ). The long, slender terminal segment bears two very long, narrow cer- copods (Pl. XX XVI, fig. 7) ending in one large and several small setie, but there is no telson; the cercopods are simple, the integument entirely smooth, with no strie or any other markings, and they are edged exter- nally with short and internally with long ciliated set. In the absence of a telson Nebalia differs from Cuma or any other Decapod, and in this respect, and the simple cereopods, shows a close resemblance to the termi- nal segment with its two setiferous cercopods of the Copepoda. Accord- ing to Claus the males differ from the female in NV. geoffroyi in the rather narrower carapace and slighter body, but chiefly in the very long 2d antenne, the flagellum of which reaches nearly to the end of the caudal appendages. The male sexual glands open on the last of the eight thoracic segments, which fact Claus regards as a proof of the agreement of Nebalia with the Malacostracous type. Internal anatomy.—Claus remarks in his “‘ Untersuchungen zur Erfor- schung der genealogischen Grundlage des Crustaceen-Systems” (1876) that in all the internal systems of organs Nebalia is considerably re- moved from the Phyllopoda, and shows an immediate relationship to the Malacostraca, sometimes approaching near the Amphipoda, sometimes near the Myside. The nervous system consists of a large two-lobed brain and of a ventral cord extending through all the limb-bearing seg- ments, there being, as shown in Metschnikoff’s Fig. 25 of the embryo, 17 ganglia, corresponding to the 17 limb-bearing segments of the body behind the head. A transverse section of a ventral ganglion of NV. bipes (Pl. XXXVI, fig. 9, or Fig. 66, in text, ng) shows a form of ganglion quite unlike that of the Hstherta and other Phyllopods (Pl. X XLV, fig. 9, ng; XXXI, fig. 8, G3, Gt; XXXII, fig. 2, ng; XIV, fig. 4, ng; XXXII, fig. 5, gang.), in which the ganglia are separate, connected by rather long transverse commissures, whereas in Nebalia the pair of ganglion are con- solidated and of the form of the Decapod ganglion, as also pointed out by Claus, who says that there is a very close resemblance in the form of the nervous centers to the ventral ganglionic chain of the Mysida. We have endeavored to obtain good sections of the brain of Nebalia bipes, and Fig. 65 (in the text) will serve to illustrate tolerably well the form and intimate structure of the supra-cesophageal ganglion. The brain is very small, and the section represented was the third from the front of the head. The ovaries (ov) pass into the head, the end of each ovary overlying the brain. The brain itself is composed of two lobes closely united, and seen in section the brain is as deep as broad, with a constriction passing around the outside in the middle. The histological structure is very simple, with nothing approaching the complex nature of the Decapodous brain. Each division or ganglion of the brain is composed of nucleated ganglion-cells, the nuclei large and distinct, as seen in Fig. 66 a, and imbedded in a fine granular substance ( punizswo- stance). At the lower part of each ganglion the fibers forming the com- missures are quite distinct. Whether the Ist antenne or both pairs are innervated from the brain Claus does not state, and we have been un- able to observe. It is probable, however, that at last the Ist antennal nerves arise from the brain, judging from Metschnikoft’s Fig. 25, wherein he shows a nerve descending from the under side of the ganglion, while the cesophageal commissures are directed backward; and we feel uncer- tain whether the descending nerves in our figure are the 1st antennal 438 GEOLOGICAL SURVEY OF THE TERRITORIES. nerves or the cesophageal commissure. Claus also likens the stalked eyes to those of Mysidw. In Nebalia no ears have been found. In the digestive canal, says Claus, we have a quite specific peculi- arity, together with approximations sometimes to the Amphipoda and Isopoda, and sometimes to the Myside and Podophthalmata. The short up curved cesophagus leads into a stomach with a complicated chitinous armature, in which an anterior and a posterior division can be distinguished. While in form and rel- ative size of both parts there is a resem- blance to the stomach of Amphipoda, so we may also observe in the position and number of the chitinous plates of the ap- ial _ paratus for triturating the food a true re- DE oo ie aa ean Semblance to the Isopoda, but also to the more enlarged to show the ganglion cells. pyloric division of the stomach of the My- roa oe sidxe, whose capacious and sack-like ex- panded cardiac division seems to correspond to the differently-formed cesophageal portion of Nebalia. The slender intestinal canal along its whole course is surrounded with a uniform layer of circular muscles, and on the inner side of the tunica propria is surrounded with a thick, fatty layer of epithelium; it reaches to the beginning of the last seg- ment, which is nearly filled by the muscular rectum (afterdarm). At the origin of the intestine (chylusdarm) arise two anteriorly and four (two larger than the others) posteriorly-directed liver-tubes; these four latter-named tubes or cceca are attached by a richly-developed fatty tissue of the serous membrane to the intestinal walls, and reach far into the abdomen. The two anteriorly-directed coeca reach to the anten- nal segment, and are frequently wholly enveloped by the fat corpuscles of their serous coat. (Compare our figure of N. bipes, Pl. XXX VII, fig. 6.) ‘The two anterior biliary ceeca manifestly correspond to those which we so often, though not always, meet with in Podophthalmatous larve (Phyllosoma, Sergestes-larve, &c.), but which, however, exist only in a rudimentary state in many Edriophthalma. The histological structure of the liver-tubes agrees closely with that of the intestine ; the circular muscles still remain, though scattered and absent at intervals. The - epithelium consists of smaller and larger cells filled mostly with large, fat cells, whose secretions, like a fluid tinged yellowish, fills the often widely distended cavity of the canals. Now, arising in a remarkable way on the under (or lower, wnterer) side of the intestine are two long ascending appendicular tubes, for the most part embedded in the fat body, which is enveloped by fat cells. The hinder intestinal appendages of Nebalia, in which we could not detect the colored secretion of the liver- tubes, remind one of the so-called malpighian tubes of the Gammaride, which arise at the beginning of the much longer rectum which passes through the three terminal segments of the abdomen. In Nebalia the relatively short rectum, by means of the numerous muscular bands sus- pending it from the intestine, performs the movements so generally ob- served in Phyllopods, by which the water is drawn in in an almost ryth- mical manner and then expelled. The anus, concealed by two triangu- lar chitinous plates of the terminal segment, opens between two small lateral flaps, which closely resemble those in the inner side of the furcal appendages of the Protozoéa larva of Penus. ‘Of the pair of tubular glands which serve in the body of Phyllopod PACKARD. ] | ANATOMY OF NEBALIA. 439 larvee as antennal and shell glands, but which in the Malacostraca un- dergo a substantial reduction, we find in Nebalia the anterior pair as slender glandular tubes in the basal joint of the 2d antenne. This re- lation of this gland, which is absorbed in the course of the metamorphosis, but in the Malacostraca, however, is generally present as a simple or winding glandular passage, affirms further the near affinity of Nebalia to the Malacostraca stem. Of the complicated shell-gland no remains survive in the Malacostraca. What we are accustomed to regard in the Decapoda as shell-glands is nothing more than the anterior gland which belongs to the maxillary region, but opens externally on the basal joint of the 2dantenne. But we can surely prove, after careful researches on living Malacostracan larve, that the rudiments or survivors of this gland are situated on the sides of the maxille (kiefer). In the Stomapod larvee I think I have found: such a survival in the shape of a simple, somewhat curved glandular tube; and also in this place the residuum of the shell-muscles are preserved. The shell or adductor muscles of Nebalia appear to be well developed, quite as in the shelled Phyllopods. On each side of the shell we observe, under the mandibles, somewhat dorsally, a large round impression with an upper and under somewhat curved row of muscle-facets. On the upper end of the group of mus- cles, however, on the inner side of the shell, is to be found a small gland- ular tube, which with a contracted neck extends to the region of the maxille, and is surely nothing else than the survivor of the true shell- gland of the Entomostraca.” Our sections of the body of Nebalia bipes show that in their general features the digestive canal and appendages are much as Claus de- scribes for the Mediterranean species. We were unable to get good sections of the proventriculus or kawmagen. Plate XXXVII, fig. 6, evidently passes through the stomach in front of the heart, which is much Fic. 66.—Section through the front end of the thorax of Nebalia bipes; ht, heart; i, intestine; ng, ganglion; vm, ventral muscle; add m, adductor muscle. Author del. larger than the intestine (fig. 7, in text). Fig. 66 (in text) is a section (No. 9) through the anterior part of the thorax, in the region of the ad- ductor muscle (add. m.); the heart (ht) is quite remote from the small intestine, which is smaller than the two anterior ceca. In Fig. 67 (in text) of section 14, through the same specimen at the end of the thorax, _ the heart (ht) is of its maximum size, and now we see sections of six 440 GEOLOGICAL SURVEY OF THE TERRITORIES. coecal tubes, the series of four lower ones being the four posterior tubes described by Claus as passing back into the abdomen. In this section the dorsal muscles (dm) of the posterior part of the body ap- pear, and the ventral muscles (vm) are larger than in section 9, while the ovarian tubes (ov) are smaller. Without translating in full Claus’ description of the heart ‘ and circulation we will only give ~~ his conelusions. The heart of Nebalia is a long straight tube a cee little thicker just in front of the middle, beginning over the max- illz just in front of the 1st thoracic segment (tergite) and extending to the middle of the 4th abdominal segment. It has two pairs of lateral large ostia for the entrance of the venous blood, and four pairs of dorsal arterial openings in the anterior part of the heart. Says Claus: “The heart combines the char- acters of Phyllopods and Mala- piste O1-—Seetion through the end of thorax of Nebalia costraca, while the tubular dor- biper, showing the six caea (cae), the heart (0), the sal vessel passing through twelve cles; vm, ventral muscles; nc, nervous cord; ov, ovary ; segments, in its form and in the Gate aa aOR greater number of ostia resem- bles the many-chambered dorsal vessel of the Phyllopods, so on the other hand the relation of the two ends with the head and abdominal aorte, together with the hinder pair of arteries, reminds us of the swift, regular, and in general complicated and vascular circulation of the Mal- acostraca. Of especial interest is the similarity of the shell, or cara- pace-circulation of the Stomapods and Mysid with Nebalia.” Of especial interest, says Claus, is the sexual apparatus, which com- bines in a surprising way in structure and form the peculiarities of Phyllopods and Malacostraca (Amphipoda), and also in position and topography retains, the primitive relation of the ovaries and testes. Both are slender, long tubes, which lie right and left on the dorsal side of the intestine from the sixth abdominal segment to the region of the stomach (kaumagen), and by means of a short cross passage open out on the thorax. In the male sex this efferent duct opens in the basal segment of the 8th pair of thoracic limbs, namely, in the same place as in the Malacostraca. Claus includes Nebalia among the Malacostraca, but when we con- sider the composite nature of the internal organs as described by him, we wonder that he failed to appreciate the independent, synthetic nature of the Phyllocaridan type, which, when we take into account the ex- ternal as well as internal organization, forbids our regarding Nebalia as a true Malacostracan, though the type of a group standing outside of, but nearer to the Malacostraca than are the Phyllopods. The development of Nebalia.—Our knowledge of the development of Nebalia is due to the distinguished Russian embryologist, who in 1868 published an elaborate account of the developmental history of Nebalia PACKARD.] RELATIONS OF NEBALIA TO THE DECAPODS. AAI geoffroyi. Unfortunately the pamphlet is in Russian, and only brief abstracts of it have appeared inGerman. But as ample and well-drawn figures illustrate the work we can state the salient points in the on- togeny of this interesting Crustacean. The yolk does not undergo total division, but by the subdivision of a large polar cell the yolk becomes surrounded by a layer of blastodermic cells. Soon after the rudiments of the two pairs of antenne and of the mandibles bud out, the abdomen also being differentiated from the rest of the body (Pl. XX X VIII, fig. 1). This is regarded as representing the free nauplius condition of other Crustacea. At a succeeding stage (Fig. 2) the two pairs of maxille and two pairs of thoracic feet bud out; and in a stage immediately succeed- ing (Fig. 3) the palpus of the mandibles elongates, the maxille are two- branched, and seven (or eight) pairs of thoracic feet are indicated. In a succeeding stage (Fig. 4) Nebalian characters assert themselves; such are the carapace and large rostrum, the biramous anterior pair of an- tenn, the unbranched 2d pair, the long mandibular palpus, the ab- sence of any rudiments of maxillipedes, and the eight pairs of thoracic feet (benopoda) and three pairs of abdominal feet (uropoda), all of which are now well developed. At this stage it may be seen that, as in spiders, the 1st pair of thoracic feet may represent the 2d maxille of insects transferred from the head to the thorax; so in Nebalia, the three first of the eight pairs of thoracic feet may correspond to the three pairs of maxillipedes of Decapods, which in early life, before the thorax is differentiated from the head, may have remained afterwards as a part of the thorax. An intermediate step is the retention in the Myside of the last pair of maxillipedes or the Ist pair of thoracic feet, so that these Crustacea have six pairs of feet. Moreover Nebalia at this time, in the absence of differentiation of thorax from the abdomen, and of thoracic and abdominal feet, the two sets being similar in form and development to each other, may also represent the Phyllopod stage. In the next stage, at the the time Nebalia leaves the brood sac of the mother, it is but one step removed, so to speak, from the adult form. Metschnikoft’s observations were made on Nebalia geoffroyi of the Mediterranean Sea. We have in the sections of Nebalia bipes observed stages of development in the young similar to the stages represented by Metschnikofi’s figure 13 or 14, and have found in the bottom of the vial in which the specimens were sent several young which had fallen out of the brood sac of the parent. Upon comparing these with Metsch- nikoif’s Fig. 19, or Fig. 68, in text, they are of the same form; the rostrum being large, the procephalic lobes large, the eyes small, the stalks not yet developed, while the maxillary palpus stretches back to the 1st abdominal feet; the thoracic feet are covered by the large carapace; and a 4th pair of abdominal feet have developed, while the caudal ap- pendages are as in the adult. In ali these features we see only a gen- eral resemblance to the Schizopods of any value, the similar earliest phases of development proving of no special importance. Comparison between the early stages of Nebalia and the Decapod (Schizo- pod) Mysis.—It would appear that if Nebalia were a Decapod that in its larval stage it should present a close homology with the Schizopods at a similar stage of existence. In Euphausia the young leaves the egg and becomes a free Swimming nauplius, and then a protozoéa, and at length a zoéa larva before assuming the adult condition. It is evident that since Nebalia passes its early stages in the incubatory pouch of the mother, that it should be rather compared with the young, when about ready to leave the mother, of some Mysis-like form. Happily Prof. G. O. Sars has afforded us the material for such a com- 449 GEOLOGICAL SURVEY OF THE TERRITORIES. parison. The early stages of Mysis, as worked out by Van Beneden and Claparede, and of Nebalia, are much alike; the formation of the blasto- derm is much the same. The nauplius stage in the egg is nearly iden- tical in both, but beyond this the parallelism ceases to be an exact one; Nebalia turns off and follows quite a different developmental path from Mysis or any Decapod. If we compare the young of Nebalia, taken from the brood-sac, with that of Mysis, as figured by Claparéde (Plate XVII, abf ant” ant Fig. 68.—Embrvo of Nebalia ready to hatch, enlarged; ant/, 1st antenne; ant’, 2d antenne; ab.f., abdominal feet or uropoda. The first maxilla crosses the thoracic feet. After Metschnikoff. fig. 6), or a more advanced stage, particularly that of Pseudomma roseum, as figured by Sars,! we shall find that many of the differential char- acters which, in the adult, separate the Phyllocarida from the Decapoda, are to be found in the young. In Mysis and allies at the same stage as Metschnikoft’s, fig. 18 of Nebalia, (our Plate XX XIII, fig. 4,) the 2d antenne are simple instead of being bifid as in Nebalia; there are no maxillipedes, and the maxille are, as in the adult, immediately suc- ceeded by the eight pairs of thoracic feet; moreover there are no ab- dominal feet in Mysis or Pseudomma, while three pairs are present in the young Nebalia. But with the exception of the lack of abdominal feet in the Myside at this stage, it may be thought upon the whole, as has already been stated by Balfour, that ‘the development of Nebalia is abbreviated, but from Metschnikoff’s figures may be seen to resemble closely that of Mysis. . . . There isin the egg a nauplius stage with three [pairs of] appendages, and subsequently a stage with the zoéa appendages.” It seems to us that the comparison” here made is, as regards any resemblance to a zoéa, loose and inexact, whether ap- plied to the Myside@ or to the Phyllocarida. The stage of the Myside succeeding the nauplius is characterized by the presence of the rudi- ments of eight pairs of appendages, the two pairs of maxilla, and the six pairs of thoracic feet of the Schizopodous type, while the zoéa has no thoracie feet at all, so that it would appear that the Schizopods do not pass through a genuine zoéa state like that of the higher Decapods. Nor on the other hand is the Nebalia stage represented by Metschni- koft’s fig. 18 (our fig. 4), a zoéa stage, for the embryo has the rudiments of eight pairs of thoracic feet, and besides those of three pairs of ab- dominal feet, while there is a well-marked carapace and rostrum, as well 1G. O. Sars, Monog. over Mysider, Heft 1. Taf. IV, fig. 23. 2Claus (Genealog. Gundlage des Crust. Systems, p. 31), as we find since writing the above, does not accept Metschnikott’s comparison of the young Nebalia with the zoéa, although he does not give the reasons for his dissent. PACKARD.] FOSSIL ALLIES OF NEBALIA. 443 as procephalie lobes with eyes, all foes parts not being developed in the embryo Myside. But whatever may be said of the FORGIMDIAN Ee between Nebalia and the Myside at an early period after the nauplius stage has been dis- earded, when we compare the later stage represented by Metschnikoft’s fig. 19 (our fig. 68, in text) with the latest larval stage of Pseudomma (see Sars’s figure, our Plate XX XVIII, fig. 5), then we see that the diagnostic ordinal characters of the Phy yllocarida have declared them- selves. There are to be seen in Nebalia the large movable rostrum, the compressed pseudobivalvular carapace, the lack of maxillipedes, the eight pseudophyllopod thoracic feet, four pairs of abdominal feet, out of the six of the adult. On the other hand, in Mysis of the same stage, the two pairs of maxillipedes are well developed, and the six pairs of remarkably long thoracic feet (the. first pair modified maxillipedes) are present. There is little to indicate that the Schizopods have descended from a Nebalia-like form, but rather from some accelerated zoéa form ; while, as we attempt in this essay to show, the Phylocarida have had no Decapod blood in them, so to speak, but have descended by a sep- arate line from Copepod-like ancestors, and culminated and even began to disappear before any Malacostraca, at least in any number, appeared. IIl.—THE PALEOZoICc ALLIES OF NEBALIA. Having studied the anatomy and development of Nebalia we are pre- pared to compare it with a group of fossil forms which are scattered through the older Paleozoic rocks from the lowest Silurian to the Car- boniferous. In a brief article’ Mr. Salter, nearly twenty years since, sketched out the characters and showed the relationship of Ceratiocaris and a number of allied forms to Nebalia in the following paragraph : ‘‘ Before the structure of Ceratiocaris was known, of which genus a reduced figure is here given, the rostral portion of Peltocaris could not have been understood. But a reference to the accompanying series of wood-cuts will show that a tolerably broad rostrum, placed in the same relative position, occurs in Ceratiocaris. In the recent Nebalia it is fixed, and in Dithyrocaris and other genera it is perhaps yet to be discovered. Again, Ceratiocaris, together with its movable rostrum, has a bivalved shell, yet habitually keeps its valves half closed, as I learn trom per- fect specimens. ey Salter then enumerates the characteristics of the fossil genera, begin- ning with Hymenocaris, which he considers the more generalized ty] pe, and in the wood-cuts which we partly here produce shows the geologi. cal succession of these genera, which also serves as a genealogical table- He regards them as Phyllopods, associating Estheria and Apus, regard. ing the latter as “the most complete and decided form, and it is one of the latest of the group, as it commences in the Trias.” He also says: “The links between these coal-measure forms and those of recent times are many of them wanting; but in Nebalia we have a good representa- tive of the compact, shield-shaped form of Ceratiocaris, the two valves soldered into one, and the rostrum attached, the eyes being still beneath the carapace.” It is evident from this that Mr. Salter regarded the fos- sil genera he enumerates as allied to and as the ancestors of Nebalia, and. as representatives of it in Paleozoic times. He evidently adopted the views of Milne-Edwards and others as to the Phyllopodous nature of Nebalia. 10n Peltocaris, a new genus of Silurian Crustacea, by J. W. Salter, Quarterly Jour- nal of the Geological Society of London, vol. xix, 1863, p. 87. A4A GEOLOGICAL SURVEY OF THE TERRITORIES. Discarding the Phyllopod forms, we here reproduce Salter’s figures and geological succession, which has been confirmed by the discoveries of Barrande and H. . Woodward. Salter’s / figure of Nebalia is, ¥ however, replaced by ‘an original one. In his article on the structure and systematic position of Nebalia,! Claus thus refers to the paleozoic forms: “Tt is generally considered that the oldest paleozoic crus- tacean remains whose shells and form of the body partly resemble Apus, and partly show a great simi- larity to Nebalia, for this reason are con- sidered to be Phyl- lopods, though we are without any in- formation as to the nature of the limbs. But now the instrue- tive error, to which the consideration of Nebalia gave occa- sion, will lead us to exercise greater cau- tion in the interpre- tation of such incom- plete and imperfectly known remains. “Tn Ceratiocaris Salter we have a great Nebalia-like carapace by which a Fig. 69.—1. Hymenocaris (Lingula Flags) ; 2. Peltocaris (Lower Silu- series of free seek rian); 3. Ceratiocaris (Upper Silurian) ; 4. Dictyocaris (Devonian) ; ments were covered, 5. Dithyrocaris (Carboniferous); (6. Argus); 7. Nebalia (Recent). and moreover 2 long well-separated lancet-formed rostrum. On the other hand, the form of the abdomen, with the powerfully developed telson beset with lateral spines, indicates a different form, which also finds expression in the appendages of C. papilio Salt. figured as antenne or thoracic ihmbs. If these representations indicate true limbs, then they remind us most of the larval limbs of Decapods. So also the position of Dictyocaris Salt. and Dithyrocaris of Scouler to the other Silurian fossils regarded as Phyllopods (Hymenoearis, Peltocaris) will remain problematical until Recent. Carboniferous. Upper Silurian. Devonian. Lower Silurian. Lingula Flags 1Siebold u. Kélliker’s Zeitschrift. xxii, 1872, p. 329. PACKARD.] THE ORDER PHYLLOCARIDA. 445 we have obtained more precise explanations as to the nature of their limbs. “It is in the highest degree probable, however, that all these forms are not true Phyllopods, but have belonged to a type of Crustacea, of which now there are no living representatives, but which, taking their origin from forms allied to the lower types of Entomostraca, have pre- pared the way for the Malacostracan type. Such a connecting link, which has served to the present day, we evidently find in the genus Nebalia.” In 1879,! without knowing the views of Claus, just quoted, we pub- lished the following brief notice of the leading characteristics of the group, and proposed that the paleozoic fossil forms, Ceratiocaris, etc., be united with the Nebaliade to form a separate order of Crustacea under the name of Phyllocarida. “The Nebaliadw, represented by the existing genus Nebalia, have generally been considered to form a family of Phyllopod Crustacea. Metschnikoff, who studied the embryology of Nebalia, considered it to be a ‘Phylopodiform Decapod.’ Besides the resemblance to the Deca- pods, there is also a combination of Copepod and Phyllepod character- istics. The type is an instance of a generalized one, and is of high an- tiquity, having been ushered in during the earliest Silurian Period, when there were, when we regard the relative size of most Crustacea, and especially of living Nebaliw, gigantic forms. Such was Dithyro- earis, which must have been over a foot long, the carapace being 7 inches long. The modern Nebalia is small, about half an inch in length, with the body compressed, the carapace bivalved as in Limnadia, one of the genuine Phyllopods. There is a large rostrum overhanging the head; stalked eyes; and, besides two pairs of antenne and mouth parts, eight pairs of leaf-like, short, respiratory feet, which are succeeded by swim- ming feet. There is no metamorphosis, development being direct. ‘‘ Of the fossil forms, Hymenocaris was regarded by Salter as ‘the more generalized type.’ The genera Peltocaris and Discinocaris characterize the Lower Silurian Period, Ceratiocaris the Upper, Dictyocaris the Up- per Silurian and the lowest Devonian strata, Dithyrocaris and Argus the Carboniferous Period. Our existing northeastern species is Nebalia bipes (Fabricius), which occurs from Maine to Greenland. ‘‘The Nebaliads were the forerunners of the Decapoda, and form, we believe, the type of a distinct order of Crustacea, for which the name Phyllocarida is proposed.” A slightly fuller account of the order was also published in the writer's Zoology,? and the order Phyllocarida was placed (pp. 325, 326) below Tetradecapods and Decapods, the scheme then presented being on the following page: On examining the figures of Salter and of Barrande, for we have been unable to study any of the fossils themselves owing to their extreme rarity, the relationship to Nebalia is very marked, as seen in the form of the carapace, the nearly free or detached rostrum, unless the separa-- tion took place after the death of the animal, and also of the rather long, slender abdomen. Upon examining theappendages at the end of the ab- domen there is to bé seen an important distinction from Nebalia; along, slender telson is usually present, with a single pair of large caudal sty- lets, or cercopoda, in form like those of Nebalia. But in Hymenocaris and Peltocaris the telson appears to be represented by a pair of small 1The Nebaliad Crustacea as types of a new order. By A. S. Packard, jr. American Naturalist, February, 1879, vol. XIII, p. 128. . 2American Science Series. Zoology for High Schools and Colleges, Ist edition, 1879. 12°. H. Holt & Co., New York. 446 GEOLOGICAL SURVEY OF THE TERRITORIES. (in Peltocaris minute) spines. In the presence of the telson in the typi- cal fossil genus Ceratiocaris we certainly have an important character separating the type with its allies from Nebalia, and allying them to the Decapods; and thus in the provisional synopsis of the order pre- sented farther on, we have placed the fossil forms in a separate suborder from the Nebaliade. CLASSIFICATION OF THE SUBCLASSES AND ORDERS OF CRUSTACEA. S j 3 > S S S SZ S S =) a o i Ss = Ss ° eS S = ~~ S S$ ~ ra i=) S S gy S (2) a RS LS aS = jointed, of which 5 or 6 segments extend beyond the carapace; the last one longest, and support- ing a strong, bulbous telson and two shorter appendages. Surface generally lineate, often finely so. C. papilio Salter, Siluria, 262, figs. 1,2, vol. 5. Great Britain. C. stygius Salter, Ann. Mag. Nat. Hist. 1860; Quart. Am. 1860, 156. Great Britain. _ inornatus McCoy, 1. c. 156. Great Britain. . murchisoni McCoy, |. c. 157. Great Britain. ', leptodactylus MeCoy, ]. ¢. 157. Great Britain. . robustus Salter, l. c. 157. Great Britain. ; . decorus Phillips, Mem. Geol. Sury. ii, Pl. 30, fig. 5. Great Britain. C C C C C C.? ensis Salter, 1. c. 159. Great Britain. C. vesica Salter, 1. c. 159. Great Britain. C. cassia Salter, 1. c. 159. Great Britain C C C C C C C . aptychoides Salter, Quart. Geol, Journ. viii, Pl. 21, fig. 10. Great Britain. . ludensis Woodw., Geol. Mag. viii, 3, 1871. (Over two feet in length.) . oretonensis Woodw., | ec. . truncatus Woodw., is Cc. .? brevicauda Salter; Bigsby, J. J. Thesaurus silur. 73, 1868. .? gigas Salter; Bigsby, J. J. Thesaurus silu:. 73, 1868. .? legumen Salter; “Bigsby. J. J. Thesaurus silur. %3; 16s. C.? perornatus Salter; Bigsby, J. J. Thesaurus silur. 73, 1868. C. bohemicus Barrande, Syst. Sil. 447, Pl. 19. - Bohemia. C. debilis Barr., 1. c. Pls. 18, 19, 26, 81. Bchemia. iC C. C. . decipiens Barr.,l. c. Pl. 21. Bohemia. docens Barr. ie c. Pl. 21. Bohemia. — inequalis Barr., 1. c. Pl. 19, var. decurtata. Bohemia. primulus Barr., "1. ¢. Pl. 18. Bohemia. ', scharyt Barr., I. ¢. Pl. 32. Bohemia. C. tardus Barr., 1. c. Pl. 18. Bohemia. C. longicaudus Hall, i6th Rep. State Cab. N. York, Pl. 1, figs. 4-7, 1863. Genesee. C. (Onchus) dewit Hall,’ Pal. N. York, ii, 320, Pl. 71, 1852. New York. C. maccoyanus Hall, Pal. N. York, ili, 420, 1859. New York State. Devonian. New York. C. acuminatus Hall, 1. c. 1859. New York. C. aculeatus Hall, 1. c. 1859. New York. ' Fig. 70.—Echinocaris punctatus ; abdomen, dorsal view, natural size. C. From Hall. C Genus ECHINOCARIS Whitfield, 1880. Carapace bivalve, valves subovate. Abdomen composed of several segments, each bearing spines on the posterior margin. Type, H. sub- levis Whitfield. E. sublevis Whitfield, Amer. Journ. Sc. 36, 1880. E. punctatus (Hall), 16th Rep. State Cab. N. Y. 74, Pl. 8, fig. 1. "1 he following species are of doubtful position (see; also, Whitfield, 1. c.): Ceratiocaris (Colpocaris) bradleyi Meek, Ohio Geol. Surv. Palzontology, Pl. 18, figs. 6a-e, 318, 1875. Ceratiocaris (Colpocaris) elytrotdes Meek, 1. c. Pl. 18, figs. 5a, 6, ¢, 319. Ceratiocaris (Solenocaris) striata Meek, 1. c. Pl. 1c, figs. 4a, b, ¢, 321. PACKARD] THE ORDER PHYLLOCARIDA. 451 E. armatus (Hall) = £. punctatus (Hall), Hamilton group, Devonian, New York. E. pustulosus Whittield, 1. c. 38, Erie shales, Devonian. Ohio. E. multinodosus Whittield, 1. ¢. 33, Erie shales, Devonian. Ohio. Genus DISCINOCARIS Woodward, 1866. Like the upper valve of a Discina, but with a wedge-shaped opening which éuts the disk nearly to its center. D. browniana Woodward, Proc. Geol. Soc. 502, 1866. Genus SPATHIOCARIS Clarke, 1882. Differs from Discinocaris in the presence of the “rostrum” or plate acting as another valve to cover the cleft, and also in its more nearly circular outline (Clarke). S. emersonii Clarke, Amer. Jour. Sc. xxiii, 477, June, 1882. 2 “SW es Fig. 71 A.—Echinocaris multi- Genus LISGOCARIS Clarke. nodosus. After Whitfield. Carapace in one piece, without evidence of dorsal suture. Periphery subpentagonal, lateral edges parallel, making sharp angles with the two anterior edges, which are re-entrantly curved, and meet in the axis of the carapace. As in _. i ‘ Spathiocaris, there is a cleft beginning centrally ee ee enc ts aU DT SES. at the highest point of the carapace. L. lutheri Clarke, 1. ¢. 478, 1882. _APTYCHOPSIS Barrande, 1872. Differs from Peltocaris in the rostrum being triangular instead of parabolical; and from Discinocaris in having no suture indicating the separation of the two principal valves. A. primus Barr. 1. c. 457, Pl. 33, 1872. Bohe- mia. Genus DICTYOCARIS Salter (1860). Carapace ample, bent along the dor- sal line, but not two-valved, largely reticulate, the area of the reticulations being convex. The shape of the car- apace is rudely triangular, pointed or rounded in front, truncate and pro- Fig. 72.—Discinocaris browniana, natural size, duced behind, and margined along the side view and disk, with the wedge-shaped ros- }]} 2 lo rong trum in situ. After Woodward. Monee and ventral edges by a st =) D. slimoni Salter, Ann. Mag. Nat. Hist. vol. 5, 1860, 162. D. ramsayi Salter, 1. c. 162. Genus DITHYROCARIS Scouler. Carapace large, apparently covering all but the last abdominal segment; “the rostrum minute or possibiy (but not probably) absent” (Salter). 452 GEOLOGICAL SURVEY OF THE TERRITORIES. Lower Carboniferous Rocks. The genus Argus seems to be the same as Dithyrocaris, although Salter does not express that opinion. Fig. 69° rep- resents Argus testudineus ; the surface of the body is striated. Dithy- rocaris pholadomyia Salter had a carapace 7 inches long. The genus Argus of Seouler is apparently the same as Dithyrocaris. D. tenuistriatus McCoy, Woodward, Geol. Mag. viii. Great Britain. D. belli Woodw. 1. c. Devonian, Gaspé, Canada. D. Neptuni Hall (Fig. 73), 16th Ann. Rep. State Cabinet, N. York. 75, Pl. I, fig. 9, 1863. Hamilton group, Devonian of New York. Fig. 73.—Dithyrocaris neptuni Bali; telson arid cercopoda, natural size. From Hall. Hall’s figure was made from a cast, no restoration having been at- tempted. From the size of the telson and the cercopods, it is evident that the animal must have been enormous, perhaps between two and three feet in length. Genus RHACHURA Scudder, 1878. R. venosa Scudd., Proc. Bost. Soc. Nat. Hist. XIX, 296. Pl. 9, fig. 3, 3a. March, 1878. Coal measures, Danville, Ohio. [) aN for) Q Vole 3 is 8 © Gr RAP aw PHYLLOPODA. a. LIVING SPECIES. . J. L. Friscu, Vom flossfiissigen seewurm mit dem Schild (Beschreibung von allerley Insecta in Teutschland, x, i, Taf. i). 1732. . R. RicHARDSON, Part of a letter concerning the Squilla aque dulcis (Philos. Trans. Royal Soc. London, vol. 38, No. 433, 331, f.). 1734. . J. TH. 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Heryricn RatuKe, Ueber Thiere welche in fast gesittigter Salzautlisung leben (Froriep’s Neue Notizen, ii, No. 27, 68-71). 1837. . H. Ratuke, Zur Fauna der Krim (Petersburg, 1836), 105-111, Tab. 6. 453. AD4 GEOLOGICAL SURVEY OF THE TERRITORIES. > 26. F. Ii. GuERIN-MENEVILLE, Note monographique sur le yenre Limnadia et descrip- tion d’une espéce nouvelle (Magasin de Zool., vii), 7, plate 21. 1837. : 27. Herc. Straus-DURKHEIM, Ueber Estheria datalacensis Riippell (Museum Sen- kenbergianum, ii, 117-128, Tab. vii). 1837. 28. AUDOUIN, Genre Cyzicus (Bulletin de la soc. entomolog. de France, 9-11). 1237. 29. N. Joty, Histoire dun petit crustacé, auquel on a faussement attribué la colo- ration en rouge des marais salans méditerranéens, suivie de recherches sur la cause réelle de cette coloration (Annal. d.sc. nat., 2. sér., xiii, 225-290, illustr.). 1840. 30. G. ZADDACH, De apodis cancriformis anatome et historia evolutionis. 4 plates. Bonne, 1841. 31. N. 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FRANZ LeypiG, Ueber Artemia salina und Branchipus stagnalis; Beitrag zur anatomischen Kenntniss dieser Thiere (Zeitschrift fiir wiss. Zoologie, iii, 280- 307, Tab. viii). 1851. 46. W. BAIRD, Monograph of the family Branchiopodiw with a description of a new genus and a species of the family and two Limnadiade (Proceed. Zool. Society of London, xx, 18-31, plates). 1852. - W. Baird, monovraph of the family Apodidz, a family of crustaceans belonging to the entomostraca with a description of a new species and two Ostracoda. (Proc. Zoogloical Soc. Lond., xx., 1-8, plates). 1852. 48. Ep. GRUBE, Bemerkungen iiber die Phyllopoden, nebst Uebersicht ihrer Gattun- gen (Wiegmann’s Archiv fiir Nat., xix, 71-172, 3 plates and appendix 247). 1853. 49. ED. GRUBE, Ueber die Gattungen Estheria und Limnadia und einen neuen Apus (Wiegmann’s Archiv. f. Nat., xxxi, 205-282, plates). 1865. 50. CHARLES GIRARD, On a new Entomostracan of the family Limnadid inhabiting the western waters (Proceed. Academy Natural Sciences Philad., vii, 3). 1854. 51. Livin, Branchipus Ondneyi, der Fezzar-Wurm (Neueste Schriften der nat. Ges. Danzig, v, 4tes Heft, pp. 10, plate). 1856. 52. A. KOZUBOWSKY, Ueber den miinnlichen Apus cancriformis (Wiegmann’s Ar- chiv. f. Naturg., xxiii, 312-318, Tab. xiii). 1857. 53. C. CHYZER and A. Toru, Beitrag zur Kenntniss des Branchipus ferox Edw. (Natur- freund Ungarns, ii, 1). 1858. 54. G. B. CRIVELLI LI, Di un nuovo Crestaceo della famiglia dei Branchiopodi Fillopodi, riscontrato nella provincia di Pavia (Memorie dell’ Instituto Lombardo di Scienze, vii, 113-120, Tav. 1). 1859. 55. CARL CLAus, Ueber die Estherien, insbesondere tiber Estheria mexicana (Beitriige zur Kenntniss der Entomostr., 12-25, Tab. ili andiv). 1560. 56. C. Ciaus, Ein Australischer Limnadia. Nachrichten von der k. Gesellschaft der Wissenschaften, 6. Miirz 1872. PACKARD.] BIBLIOGRAPHY. 455 57. C. Ciaus, Ueber den Korperbau einer australischen Limnadia und iiber das Miinnehen derselben. Zeit. f. wissen. Zool. xxii, 355. Taf. xxix, xxx. 1872. 58. B. von DyBowsk1, Beitrag. zur Phyllopoden-Fauna der Umegegend Berlins (Wieg- mann’s Archiv f. Nat., Xxvi, 195-204, plate). 1860. 59. J. LUBBOCK, Notes on some new or little known species of freshwater Entomos- traca (Transact. Linnean Soc, Lond., xxiv, 197-209). 1863. 60. KLUNZINGER, Beitrige zur Keuntniss der Limnadiden (Zeitschr. f. wiss. Zool. xiv, 139-164, plates). ‘1864. 61. LEREBOULLET, Observations sur la génération et le dévelopement de Ja Limnadia Hermanni Brongn. (Annales d. science. natur., 5. sér. Zoolog., v, 283-308, plate). 1866. 62. A. Frrescu, Ueber das Vorkommen von Apus und Branchipus in Boehmen (Ver- handl. d. zool. bot. Ges. Wien, xvi, 557-562). 1866. 63. R. BucuuoLz, Branchipus Grubei Dybowsky (Schriften der phys. 6k. Gesellschaft VAN Koniesberg, v, 93-107, plate). 1866. 64. KLUNZINGER, Ueber Branchipus rubricaudatus n. sp. (Zeitschr. f. wissensch. Zool., xvii, 23-33, plate). 1867. 65. E. 8. Morse. Proc. Boston Society Nat. Hist., xi, 404. 1866-’68. 66. E. 8. Morse. First Book of Zoology. New York, 1875, 120 (Estheria and Lim- nadia figured). 67. A. E. VERRILL. Descriptions of some new American Phyllopod Crustacea. Contr. to Zool. Mus. Yale College, No. iii. Amer. Journ. Sc., 244, xlviii. 1869. Ann. and Mag. Nat. Hist. London, 1869. 68. A. E. VERRILL. Observations on Phyllopod Crustacea of the family Branchipida, with descriptions of some new genera and species from America. Proc. Amer. Assoc. Adv. Se. for 1869. July, 1870. 69. W. LittyeBoRG, Limnadia gigas (J. F. Hermann) forekommande i Sverige in “Porhandlingar af Kongl. Vetenskaps-Akadem.,” Stockholm, 1871, 823-844, 24 plates. 70. W. LILLJEBORG, Synopsis Crustaceorum Svecicorum ordinis Branchiopodorum et subordinis Phyllopodorum. pp. 20. (Reg. Soc. Se. Upsaliensi tradita die vu, Apr. 1877. 71. A. S. PACKARD, JR. Preliminary notice of new North American Phyllopoda. Amer. Jonrn. Sc. and Arts, ser. 3, ii. August, 1871. 72. A. S. PACKARD, JR. Descriptions of new North American Phyllopoda. Sixth Re- port Peabody Acad. Se. Salem, Mass., 54. 1874. 73. A. S. PACKARD, JR. Synopsis of the fresh-water Phyllopoda of North America. Rep. U. $. Geol. Survey Terr. (F. V. Hayden in charge) for 1873. Zoology, 613. 1874. 74. A §. PackarD, JR. New Phyllopod Crustaceans. American Naturalist, ix, 311. May, 1875. 75. A. S. PACKARD, JR. Explorations of the Polaris Expedition. Amer. Nat. Jan- uary, 1877. 76. A. 8. PacKaRD, JR. Descriptions of new Phyllopod Crustacea trom the West. Bulletin U. S. Geol. and Geogr. Survey (F. V. Hayden in charge), iii, No. 1, 171. April 9, 1877. 77. A. 8S. PACKARD, JR. Occurrence of the Phyllopod Eubranchipus in winter. Amer. Nat., xii, 166. March, 1878. 78. A. 8. PACKARD, JR. Notes on Phyllopod Crustacea. Amer. Nat., xiv, 53. Jan- uary, 1880. 79. A. S. PACKARD, JR., A new Distomum parasite in the egg-sacks of Apus. (Disto- mum apodis) ’American Naturalist, 142. Feb. 1882. 80. FRIEDRICH BRAUER, Beitriige zur Kenntniss der Phyilopoden in Sitzungsberichte der k. Akad. d. Wissensch., Ixv. Band, lte Abth., 1 plate, 1-13. Wien, 1872. 81. FRIEDRICH BRAUER, Vorliinfige Mittheilungen iiber die Eatwicklung und Leben- sweise des Lepidurus productus Bose. In Sitzungsb. d. k. Akad. d. Wiss. Wien, Band Ixix, Ite Abth. 1-12, 2 plates. 1874. . 82. FRIEDRICH BRAUER, Beitriige zur Kenntniss der Phyllopoden. Sitzungsberichte der k. Akod, d. Wissen. Wien., Math-Naturw., Classe, xxv. Band, v. Heft, 583, 8 Tak. 1878: 83. G. O. Sars, Bemerkninger om de til Norges Fauna horende Phyllopoder in Vi- densk. Selsk. Forhandlinger, 3-7. 1873. 84. F. SPANGENBERG, Zur Kenntniss von Branchipus stagnalis. Zeits. fiir wissen. Zool., xxv. Supp. Heft, 1, Taf. i-iii. 1575. 85. I. SpANGENBERG, Bemerkungen zur Anatomie der Limnadia Hermanni Brongn. Zeits. f. wissen. Zool., xxx. Supp. Band, 476. Mai, 1878. 86. HEINRICH LENZ, Estheria californica Packard. Inaug. dissertation, 24-40, 2 plates. Rostock, 1876. 87. H. Nirscuer, Ueber die Geschlechtsorgane von Branchipus Grubi. Zeits. f. wis- sen. Zool., xxv. Suppl. Band, 281. Taf. xxii, Dec. 22. 1675. 456 GEOLOGICAL SURVEY OF THE TERRITORIES. 88. 89. 90. ke 92. 99. J. A. RyvEr, Description of a new species of Chirocephalus (Ch. Holmani). Enocced: a the Academy of Natural Sciences, Philadelphia, 3 wood-cuts, 148- 149. 1876 J. A. Ryprr, Description of a new Branchipod. Proceed. of the Acad. of Nat. Sciences Philad., 200-202 (Streptocephalus Sealii), 1 wood-cut. 1879. J. WLADIMIR SCHMANKEWITSCH. On Branchipus. Schriften deriii, Versammlung Russisch. Naturforschen, Zcolog. Theil. J. WLADIMIR SCHMANKEWITSCH. Sitzung der neurussischen Gesellschaft der Naturforscher in Odessa, Sept. 20, 1574, ii, Th. ii. W. J. SCHMANKEWITSCH, Ueber das Verhiltniss der Artemia salina Miln.-Edw. zur Artemia Muhlhausenii Miln. Edw. und dem Genus Branchipus Schaef. Zeits. f. wissen. Zoologie, xxv. Supp. Heft, 103, Taf. ti. 1875. . J. WLADIMIR SCHMANKEWITSCH, Zur Kenntniss des Einflusses der diusseren Lebens- bedingungen auf die Organisation der Thiere. Zeitsch. ftir wissensch. Zoologie, xxix, 429-494. 1877 CaruL I. GISSLER. Description of a hermaphroditic Phyllopod Crustacean (Hu- branchipus vernalis), American Natnralist, 136, xv. February, 1881. . Cart EF, GisstER. Evidences of the eifect of chemico-physical influences in the evolution of Branchiopod Crustaceans. American Naturalist, 280, xv. April, 1881. b. Foss1~ PHYLLOPODA. T. RuPERT JONES, A monograph of the fossil Estheriz. Lond. Palzont. Society, 134, 5 plates, 4°. 1862 . T. RUPERT JONES, On fossil Estherie and their distribution (Quarterly Journ. Geol. Soc. Lond., xix, 140-157.—Natural Hist. Review, 262-276. 1803. . T. RUPERT JONES, Note on Estheria Middendortii (Quart. Journ. Geol. Soc. Lond. xix, 73). 1863. H. LASPEYRES, Das fossile Phyllopoden-Genus Leaia Jones (Zeitschrift der deut- schen eeolow. Gesellschaft, 733-746, 1 plate). 1870. 100. A.S. PACKAI D, JR., A fossil Phyllopod Crustacean from the Quaternary clays of Canada. American Naturalist, 496, xv. June, 1381. 101. Joun M. CLARKE, New Phyllopod Crustaceans from the Devonian of Western New an Re wwOeS NSD York. Amer. Journ Sc., 476, xxiii. June, 1852. PHYLLOCARIDA. a. LIVING SPECIES. . HENRI MILNE-EDWAnRrpDs, Annales des Sciences Naturelles, tome xiii, 1828. . HENRI MItNE-Epwarps, Annales des Sciences Naturelles, 2. sér. , tome iil, 1835. . HENRI MILNE- EDWARDS, Histoire Naturelles des Crustacés, tome iii, P: ris, 1840. . Henrik Kroyer. Karcinologiske Bidrag. Naturhistorisk Tidskrift, ser. 2, li, 436, 1847. . ELIAS METSCHNIKOFF (Abstract of Embryology of Nebalia). Sitzungsberichte der Naturforscherversammlung zu Hanover, 1865, 218. Also Keferstein’s Jahresber- icht, 1867. . EIAs METSCHNIKOFF, Development of Nebalia (in Russian). 1868. 8°, 48, 2 plates. . Fritz MGLuER, Fiir Darwin. Leipzig, 1864. 5°. (Facts and Arouments for Dar- win. By Fritz Miiller, with additions by the author. Translated by W. 8. Dallas. London, 1869), 12, 144. . C. CLaus, Ueber den Bau und die systematische Stellung von Nebalia, nebst Be- merkungen iiber das seither unbekannte mannchen dieser Gattung. (Zeits. f. Ww. Zoologie, xxii, 323, Taf. xxv). 1872 . C. CLAUS, Nachrichten von den kénigl. Gesellschaten und der G. A. Universtiit, VAN Gottingen, No. 10, 1871. . C. Ciaus, Unter suchungen zur Erforschung der genealogischen Grundlage des Crus- taceen- “Systems. Ein Beitrag zur Descendenzlehre. Wien, 1876. . R. VON WILLEMOES-SuagM, On some Atlantic Crustacea from the Challenger Expe- dition. III. On a Nebalia from the Bermudas, pl. vi. Trans. Linn. Soe., 2d ser., A 26, 1875. A. S. PACKARD D, jr., The Nebaliad Crustacea as types of a new order (Phyllocarida) American Naturalist, xiv, 28, Feb., 1879. Annals and Mag. Nat. Hist. London, 1880. . A. S. PACKARD, jr., Zoology for High Schools and Colleges. New York, Dec., 1879. (Order Phyllocarida described.) “PACKARD.] BIBLIOGRAPHY. 457 oD. 36. Bye b. FOSSIL SPECIES. . McCoy, Annals and Magazine of Natural History, ser. 2, vol. iv, 412, 1850. 5. McCoy, Synopsis of British Palaozoic Fossils Cambridge Museum, tase. i, 136, Pl. I, E, 1851. . McCoy, Quart. Journal of the Geological Society of London, Feb., 1853, 13, 1853. . JAMES HALL, Paleontology of New York, ii, 320, pl. 71, 1852, . JAMES HALL, Paleontology of New York, iii, 420, 1859. 16th Ann. Rep. Stat. Cab- inet of Nat. Hist, New York, App. D. ’ Albany, 1863. . R. MURCHISON, Siluria, 236, 1854. . J. SALTER, On some new Crustacea from the uppermost Silurian Rocks. Proce. Geol. Soc. London. xii, 26, 1856. Quart. Journ. Geol. Soc. London, 33, xii, Feb., 1856. J. SALTER, On new fossil Crustacea from the Silurian Rocks, Annals of Natural Hist., 3d ser., v, 153-162. March, 1860. . J. SALTER, On Peltocaris, a new genus of Silurian Crust. (Quart. Journ. Geol. Soc. Lond., xix, 87-92), illustr., 1863. J. SALTER, On some tracks of Lower Silurian Crust. (Quart. Journ. Geol. Soe. Lond., xix, 92-95, illustr.), 1863. . J. SALTER, Memoirs of the Geological Survey of Great Britain, iii, 294, 1866. . ANGELIN, Pal. Scandin, Suppl. Pl. B, 1850. . HENRY WOODWARD, On the oldest known British Crab; notes on the species of the genus Eryon Desm., and on a new genus of Phyllopodous Crustacea (Quart. Journ Geol. Soc. Lond., vol. xxii, 49 3-505, 2 plates). 1866. . HENRY WoopWARD, On some new Phyilopodous Crustaceans from the Paleozoic rocks (Geolog. Magazin London, vol. viii, No. 3, 3-6, plate iii, 1-5). 1871. . HENRY WOODWARD, “On Fossil Crustacea (Geological Magazin Lond., vol. vill, No. 11, 1-4). 1871. . J. J. BiGsBy, Thesaurus Silur., 73, 1868. . JOACHIM BARRANDE, Systéme Silurien du Centre de la Bohéme, vol. i, suppl. Pragne 1372, 435-459. (Also Jahrbuch, von Leonhard und Bronn, Heft iii, 322, 1853.) . HENRY Woopwanrb, Geological Magazine, ii, 401, pl. xi, 1865. . J. SALTER and HENRY WOODWARD, Chart of Fossil Crustacea, 1865. . HENRY WOODWARD, Geological Magazine, iii, 203, pl. x, 1806. . R. P. WHITFIELD, Notice of new forms of Fossil Crustaceans from the Upper De- vonian Rocks of Ohio, with descriptions of new Genera and Species. Amer. Journ. Se., 3d ser., xix, 33. Jan., 1880. R. P. WAITFIELD, Geol. Surv. Ohio, Paleontology, iii. 8S. H. ScupprEr, Rhachura, A new Genus of fossil Crustacea (Rhachura venosa. Scudder. Danville, Ill., Bed, No. 14, Coal Measures). Proc. Boston Soc. Nat. Hist., xix, 296, Pl. 9, fig. 3, 3%. March, 1878. JOHN M. CLARKE, New Phyllopod Crustaceans from the Devonian of Western New York. Withaplate. Amer. Journ. Se., 476-8, xxiii. June, 1882, APPENDIX. A.-ON ARTEMIA FERTILIS VERRILL, FROM GREAT SALT LAKH, UTAH TERRITORY.! By Pror. C. TH. VON SIEBOLD, of Munich. [Translated by Dr. Phil. Carl F. Gissler, of Providence, R. I.] Having positively convinced myself several years ago that Artemia salina, which is known to inhabit in countless numbers shallow brackish water ponds along the shores of Europe, in those localities propagates parthenogenetically without males,? I put to myself the question whether this was also the case with other species of the genus Artemia. To solve this problem I conceived the idea of procuring live specimens of the brine-shrimp from the Great Salt Lake of Utah, which I knew to occur there in both sexes and in great numbers. The middle of March this year (1876) I obtained, through the kindness of Dr. Hermann A. Hagen, of Cambridge, Mass., a considerable quantity of dried mud from the Great Salt Lake, with which I experimented in the following manner: Toward the end of March, of the same year, I divided some of the dried mud into several shallow glass jars, pouring over it on the 6th of April artificially prepared sea-water, using common hydrant- water and Reichenhaller brine. On the 8th day of April already the water in one of these jars swarmed with Nauplii, the hatching of which I eagerly watched, as I observed many brown Artemia eggs on stirring up the mud infusions. The brood prospered excellently, the mud being evidently impregnated with organic matter, the latter serving as food during their different moults and stages of development; and already on April 16, about eleven days after hatching, indications of sexual characters could be perceived, in the male sex perceptible by a stouter swelling of the claspers. This sexual character, after which the dif- ferentiation of the organs of reproduction appear, refers to the organs of copulation only, and not to the true fructification organs, and was for my experiments of great importance. This early differentiation of the male and female individuals of Artemia fertilis gave me occasion to distinguish the males from the females, and to keep them separate al- ready at atime before the internal sexual organs, the testicles of the males and the ovaries of the females, began to develop. The second pair of legs of the six-footed Nauplius is, after the first moult, promi- Utah. Von Prof. C. v. Sieboldin Miinchen. Separatabdruck ans den Verhandlungen der 5¥ten Jahresversammlung der Schweiz. naturf. Gesellschaft in Basel, 1876. Basel, 1877. 8°. pp. 16. So much that is of great interest in connection with the doctrine of evolution and of parthenogenesis has been published regarding the Phyllopods, that we avail our- self of the kind permission to insert, as an appendix, the most important papers which have appeared. I am indebted to Dr. C. F. Gissler for this and the following transla- tions and abtracts. 2See my lecture on ‘‘ Parthenogenesis of Artemia salina,” in the Sitzungsberichte der mathematisch-physikalischen Classe der K. Akademie der Wissenschaften, of June 7, 1873, p. 163. 459 460 GEOLOGICAL SURVEY OF THE TERRITORIES. nently developed, serving as a rudder organ; after the subsequent moults this organ becomes gradually shorter, less movable, bent down, © loses its bristled margin, and in the females is transformed into two small, scarcely movable, tongue-like bent processes, while in the males the same develops itself into disproportionately large claspers with broad lobes, functionating as a catching and clasping apparatus. These robust claspers, bent downwards and backwards, betray the male sex, as above stated, in the earlier stages by an incipient swelling of the said rudder organs, while the same, after their hystolytic degeneration, re- main small in the females. In this way it was easy for me early to dis- tinguish the males from the females and, significant for my experiments, to keep them apart. The growth and prosperity of the carefully-separated sexes proceeded well in various jars with artificial sea water, and pains were also taken to add only boiled Utah mud to prevent any Artemia eggs from hatch- ing. Without this precaution L would eventually have received younger broods of different sexes together with the older ones, already kept apart, which would have interfered with my experiments, in which latter the utmost certainty was required to prevent the meeting of the two sexes before the setting in of concupiscense. Having raised a large number of carefully-watched virgin individuals in the above mentioned manner, I waited the period of concupiscence in one-half of their num- ber without giving them occasion to come in contact with any males, while the other half of virgins I placed together with a number of ma- tured male individuals for the purpose of getting fertilized by them. I succeeded in this, since the males very early, as already stated, betrayed their future sex and were vigorously grown up, and gave repeated indi- cations of sexual desires. They manifested the latter in their pugna- cious behavior, embracing themselves with their powerful claspers in such a manner as if they would perform copulation; many ot them clasped cther males, no matter how they struggled against it, and with such a violent fervor that they, as may be assumed, applied the claspers on alinost every part of their body. Such couples remained entangled for several days, Swimming around in the most unnatural positions. The testicles, filled with whitish zodsperms, presented themselves to the naked eye through the translucent body. I selected the most vigor- ous individuals, placing them ina jar together with boiled-up Utah mud and a number of virgin Artemiz, and had then very soon the pleasure to see that they did not refuse the ardent embraces ot the males, the females making no efforts to free themselves of their burden. The male with its claspers embraces the postabdomen of the female from the back, which region appears swollen by the ovisac. In this way both individuals, bearing their abdomens parallel above each other, swim about as if animated with but one will. From time to time such a couple swims along the surface of the mud, turns around its longitudinal axis. dorsal side up, thus whirling up the loose mud for the purpose of obtaining food. Occasionally the male, utilizing the embrace of the female, bends its postabdomen around for the purpose of inserting its two protrusile cylindrical copulative organs into the female genital orifice, whereby the closest contact with the female, as well as an afflux of spermatic particles, was effected> The actual process of copulation, as closely observed by me, was interrupted after shorter or longer intervals, but in incessantly long- continued embraces it was often repeated. One of these couples hung togethcr for three days. After copulation ensued, I transferred those females which were abandoned by their males and which females I re- PACKARD.] ARTIFICIAL REARING OF THE BRINE SHRIMP. A461 garded as fecundated into a new jar, into which they could eventually deposit their eggs. But to be sure that no new brood of Artemia was developed out of the Utah mud added as food, I again took the pre- caution to use only well-boiled mud in which any possible eggs would then be destroyed. The fecundated Artemia females, however, con- tinued to prosper in their new jar, and I soon perceived the activity of their inner generative organs. This activity manifested itself very soon in the two blind ovarial strin gs situated in their postabdomens; in the interior of those strings white, uniseriately-placed ovarial germs came into view, which latter grew more and more, their places of contact be- coming flattened. All “these eggs in their complete form possessed neither a germinal vesicle nor a yolk-skin. The latter is not formed until the uncovered eggs have entered the upper bent-inward-and-back- ward end of the ovarial strings, and then it represents a very tender trans- lucentand homogeneousegg-membrane. I should call these bent terminal portions of the ovarial tubes oviducts, since they enter after a short course a capacious cavity, the latter certainly functionating as an uterus. The uterus possesses in its walls a very ‘complicated muscular appa- ratus, which, through its active contractions, moves the contents of the uterus in various ways. One can now also observe six cell complexes in three pair of groups on the right and left behind each other, divided and fastened to the uterus walls, which in their organization and mean- ing fully correspond with the egg-shell glands, as observed and de- scribed! by me in Artemia salina, only with the difference that in Artemia fertilis three pairs, in A. salina only two pairs of such shell- glands occur. These glands at first appear perfectly colorless, becom- ing gradually amber-yellow, finally assuming a rust-brown color, with which coloration the secreting function of these glands begins. It was now interesting and striking to me in these investigations that the first lot of eggs that entered the uterus through the oviduct, which eggs were surrounded by but a delicate yolk- -membrane, did not yet receive any hard egg-shells, although they were incessantly moved to and fro by the muscular walls of the uterus. They remained without shells, because the shell-glands had not yet discharged their contents into the uterine cavity. Un the other hand, to my greatest astonishment, a perfect segmentation process was eoing on in the uncovered eggs, which could be closely followed through the tender and transparent yolk-skin. Finally, I perceived the red eye-dot of the now developed Nauplius through the yolk-skin, soon afterwards the entire brood of Nauplii escaping and rowing about in the water. Curiously enough, this parturitive act did not repeat itself in all those females of Artemia which gave birth once, although their uterus was repeatedly filled with tender-skinned eggs; in short, all fertilized females of Artemia fertilis became, after first. giving birth to live young ones, from this time ovip- arous.”, Whether now all females of Artemia fertilis show the pecu- liarity of always producing live young ones at the first process of propagation and then become oviparous, I can give no decisive answer. The observation seems to me important, which I here, though already mentioned, again repeat, that in raising Nauplii from the ‘¢ Dauer- 1 Opus citatum, p. 191. 2T had already occasion to make similar observations on A. salina, and refer to p. 190 of op. citat., and there I attempted to express presumptions as to the causes which induce the females of Artemia at one time to be viviparous and at other times ovipa- rous ; tbe correctness of those conjectures I cannot warrant, since I have not yet ac- quireil the necessary amount of experience on these striking phenomena. 462 GEOLOGICAL SURVEY OF THE TERRITORIES. eges”! contained in dried Utah mud, male as well as female Artemie, and both in about the same number were obtained. To these observa- tions I have to annex the following, which, as regards the questions what sex issues in the different manners of propagation in the Nauplii, in future will turn out to be important. Namely, I refer to the fact that also those Nauplii, which the fecundated, primiparous females of Ar- temia Jertilis, raised from ‘ Dauer-eggs,” ‘yielded in exactly the same manner, like those Nauplii hatched from ‘ Dauer-eggs” contained in Utah mud, male and female individuals of Artemia fertilis. Concerning the manner of propagation going on after (emmalig) vivi- parturition and oviposition of the fecundated females, I have to say that this process of oviposition occurs in the same manner and with the same repetition as observed by me in non-fertilized females, and which I shall describe later. As the second part of my report on the domestication (Zeuchtung) of Artemia fertilis I have to mention experi- ments through which I tried to force this: Branchiopod to produce par- thenogenetic generations. In how far I did or did not succeed in these experiments I cannot yet call to account, since I till now could realize only preparations and introductions for the same. I only want to state how | succeeded in obtaining the material with which I could convince myself whether Artemia fertilis, like A. salina, possesses the peculiarity under certain circumstances to propagate parthenogenetically. It was easy for me to procure the necessary material, since I kept separate, as already stated, a jar with Artemia, which showed in their earlier devel- oping stages indications of yielding female individuals. From this jar I selected such females in which the first traces of concupiscence were noticed, and those I raised separately in a jar with brine water and boiled Utah mud, watching them carefully to prevent any access of males, and to let them, as genuine virgins, become coneupiscent.? At the time when in these isolated virgins the generative organs attained maturity, which showed itself in the ovaries distended with germs, my particular attention was directed to the jar containing them. There I noticed that in these virgins the eggs entered from the ovaries into the oviduct, whence they accumulated in the uterine cavity, during which time the six above-mentioned shell-glands assumed a brown color. Later on the amber-colored secretion of the glands discharged into the uterus, flowing around the tender-skinned unfecundated eggs, which latter, kept in rhythmic motion by the contractions of the muscular walls 1 Above I make use of the word ‘‘ Dauer-eggs” (or permanent eg gs) avoiding the hitherto customary specification ‘‘ winter-eggs” as not quite proper. Of course (allerdings) most Phyllopods deposit two different kinds of eggs, one kind of which develops soon after being deposited, while the other kind hatches after a very long time, and in our climate, in most cases, after hibernation. But those latter ergs can also endure two or more winters under casual external conditions, if the neces- sary impulse from outside for the hatching of the eggs continues; I mean to say when the suitable moisture, giving action and completion for the development of those Phyllopods, does not come into effect. In this way it is accounted for that in such pools serving as a habitation for Phyllopods, but which remain dry for several years and which afterwards again become filled with water, the long disappeared Phyllo- pods suddenly reappear, as the there buried winter eggs (or better) ‘‘ Dauer-eggs,” under the influence of the water become animated to live activity out of the latent condition. 2 'To demonstrate during my lecture I prepared three jars with mud and salt water, into which I divided three different objects concerning Artemia in the following man- ner: One jar contained several full-grown males, the “second jar contained fertilized egg-bearing females, together with two entang led copulating couples, while the third jar, contained virgin females, bearing non- fertilized eggs. These Artemia arrived in goode condition, after being conveyed in their jars from Miinchen to Basel, and there could be exhibited alive during the lecture. PACKARD. ] PARTHENOGENESIS IN ARTEMITA, 463 of the uterus, became darker and darker and surrounded with a hard brown shell, so that the non-fecundated, differed neither in form nor. color or structure from the fecundated ones. The virgin Artemiz depos- ited their eggs some time afterwards, dropping them into the mud at the bottom of the jar. The uterus of such unfertilized females appeared to be empty after the eggs were dropped; their shell-glands were pale, but their ovaries again contained new germs, which gradually devel- oped, while the pale shell-glands, after some time, again assumed their brown color, and I surmised that they prepared themselves once more for ovipositing non-fecundated eggs. The same process reoccurred several times in virgins, the latter not differing therefore in this respect from fecundated ones. In this manner I succeeded in accumulating a large number of non-fecundated eggs in the mud of the jar prepared for the concupiscent, non-fertilized females. I must now draw your attention to the fact that such oviparous virgins were never viviparous before depositing eggs. For the success of my experiment on parthenogenesis this was a bad omen. It is evident, however, that the primiparturition of live young ones is not realized in virgin females of Artemia fertilis ; but it is, nevertheless, possible that the ‘“ Dauer-eges” dropped by the virgins possess the peculiarity of developing themselves without fertili- zation, and do yield females, and therein we would have again a con- tribution to our knowledge on the distribution of parthenogenesis. I shall preserve during the coming winter (1576-77) the different kinds of dried mud which are partly impregnated with fertilized, partly with non-fertilized ‘ Dauer-eges” of Artemia fertilis, for the purpose of examining next spring whether the mud with fertilized eggs alone, or besides it, also the mud with non-fertilized eggs, will yield Nauplii, when it will be of importance to learn from what set the parthenogenetic Nauplii develop themselves. B.—PROF. CARL THEODOR VON SIEBOLD ON PARTHENO- GENESIS IN ARTEMIA SALINA|! ABSTRACT. By Dr. C. F. GISSLER, Owing to the remarks expressed two years ago in my paper “ Beitrige zur Parthenogenesis der Arthropoden” (Leipzig, 1871, p. 197), I am in- debted to Prof. Carl Vogt, of Geneva (Switzerland), for a lot of live in- dividuals of Artemia salina, which arrived at Miinchen August 27, 1872. I was very pleased to have received seventy live and five dead speci- mens, together with a number of larve, in a jar of salt water. All the full-grown individuals were females, which was also the case with a num- ber of Artemize Dr. Vogt received from Professor Martins at Cette. I observed that in all the seventy specimens thus obtained the egg-sac was filled with embryos. The various behavior of this brood attracted my special attention. Having dissected the egg-sac of a dead individual, I noticed several live embryos escaping from the same, together with a few pear-shaped bédies of orange color sinking to the bottom. The lat- ter proved to be also embryos inclosed in a homogeneous thin egg skin. The outlines of the inclosed embryos could be distinctly seen through the egg skin, as well as the motions of the embryo. Such viviparous 1“Sitzungsberichte der mathematisch-physicalischen Classe zu Miinchen, 1873, Heft. II.” 2 464 GEOLOGICAL SURVEY OF THE TERRITORIES. Artemiz I also observed amongst the other live specimens. . After the -eseape of the brood the egg skins remained in the egg-sacs. But many Artemiz proved to be also oviparous. The egg-sac in such oviparous specimens then contained brownish spherical, hard-shelled eggs. In breaking this brittleshell between two glass slides the homogeneous inner egg skin could be noticed. Joly, who also observed this mode of multi- plication, supposed the season of the year had something to do with it. Vogt noticed that they became oviparous when kept in a more capa- cious vessel, and viviparous when kept in small jars. I, myself, did not succeed in raising more than two generations. Not a single male indi- vidual was obtained from the young Artemiz received as viviparous generation; only 35 females attained sexual maturity. Of these 35 females, on the 20th of October the largest ones had soft, white eggs in the egg-sac, which became gradually brown in a few days; some had their eggs deposited on November 5, involving at the same time a cer- tain mortality among my specimens, all having died by November 21, 1872. The deposited egg did not hatch. After this unsuccessful attempt I concluded to get some more fresh material, which was forwarded to me through the kind intermediation of Duke Carl Theodor of Bavaria, of whose active interest in natural science I was aware. On the 3d of December I received two bottles with 50 live Artemizw, which were collected near Capodistria by Dr. Syrski, of Triest, also a large bottle of marine mud and fresh sea water. The Artemiz were, though dead, still of a fresh appearance. They were all females, and their egg-sacs were crammed with brown eggs. After re- moving the eggs [ placed them in a shallow vessel with marine mud and sea water. Already four days afterwards I observed new-born em- bryos swimining about, and many more toward evening. I divided them on December 12 in two jars, marked with a and b. Owing to the marine mud containing much organic matter (which was probably not the case in the former experiment) they prospered well, shed their skins often, and developed into females. The jar destined for the specimens origin- ally received froin Capodistria I marked with e. The embryos hatched therein from the eggs of the killed original specimens and those embryos I divided into the two jars a and b. That the embryos thus hatched did not all come from the eg ges taken from the egg-saes of the original dead but still fresh specimens is quite obvious, as the marine mud very likely also contained eggs of Artemia, which were thus brought to development. Finally I got ‘fully convineed of this view, as in the “larger jars a and b gradually an immense number of young Artemiz grew up, whose number by far exceeded the sums of those embryos which I took from jar e, and which I placed into the jars aand b. In no ease could this superfluous brood have originated from the older, fully-raised embryos, as the latter were not yet sexually ma- ture when I noticed the bulky throng of continually forthcoming em- bryos. On examining a quantity of the remaining mud from Triest I found many Artemia eggs. The hatching of embryos in jar e kept on from December 7, 1872, till March 23, 1873. Some marine mud I placed also into jars a and b, and care was taken to replace the evaporated salt water, a water of 19 Beaumé having been used for this purpose. On January 12, 1873, I counted 31 full grown and 136 younger individuals, not counting the very youngest ones. In the ovaries of seven adult females I noticed on January 19 the first traces of egg-formation; on the 24th I saw the yellowish eggs in the ovaries in 18 adult ones; 4 of them had yellowish eggs in the egg-sacs, and 3 had brown ones; on January 26th 3 more had also brown eggs in the egg-sacs. PACKARD.] PARTHENOGENESIS IN ARTEMIA. 465 To verify whether those eggs were really unfertilized, I arranged another large jar with artificial sea water and marked it with fZ Into this jar I placed some Triest marine mud which had been previously boiled to destroy any eggs possibly contained therein. The adult females placed in this jar prospered well. The number of adult females in jars a and Db continually increased, counting, on February 1, 24 fe- males, all with brown eggs in their egg-sacs. Six of these females dropped their eggs on February 5, their ovaries again showing activity. IT again arranged another jar, bearing the letter 4, placing previously boiled toud into it and those 6 females, whose egg-saes, on February 16, contained for the second time brown eggs, and again the same day I placed 8 more specimens into it, taken from jar /, which afterwards prepared themselves for a third oviposition, so that 1 was urged to take for those 14 females another moderately large jar, bearing the letter 4, to allow them to deposit for a third time. “On March 2 this jar i was arranged with the 14 females, the latter depositing their sas during March; on April 15 ajar marked m was prepared with boiled mud placing 2 females into it from j jar 7, which were about to deposit for the fourth time. ©n May 4 one of the two deposited for the fourth time, and al- though a fifth series began to form, I did not prepare another jar; the specimen showed great weakness, and died subsequently. As a matter of course the females taken from jars a and b multiplied in the jars f, h, i,m. In jar f, out of which I took, up to February 28, 14 females and placed them into jar hk, L counted, on April 6, 39 females. It would be too tiresome to put down here all the notes as ‘wrote them down seriatim in reterence to further development of Artemia, and I shall here briefly state the result of my experiments. The eggs were for the greater part on the surface of the muddy bottom. On March 16, being the 40th day after my first raised virgin Artemiz deposited their eggs, I noticed two embryos of the Nauplius-stage, as tigured by Joly. For the sake of maintaining stricter control ot the embr yos, of whose parthenogenetic origin I had to be fully convinced, I placed these, as well as all those later hatched in jar f, into a smaller jar, 9, with some previously boiled Triest mud. On March 24 I had eight such embryos in jar g; counting on March 30, 22; and up to May 10 I had transferred 71 embryos from jar f into jar g. Henceforth the ue velopment in jar f increased rapidly (May 11, hatched 25, and May 49 embryos), so that up to May 23 I obtained from jar f 402 embryos os. In this manner I verified that from eggs deposited by virgin females of Ar- temia salina, which were not fertilized by any male sperm, a brood can de- velope. The empty egg-shells were found to be partly floating on the surface or hidden in the mud at the bottom. The fresh unhatched egg never swain on the surface, and the empty egg-shells on the bottom all showed a crack. Seventeen embryos were removed from jar g and placed in a jar marked k, with a quantity of prepared (boiled) Triest mud. This was done for better observing the sexual development. Of these 17 indi- viduals 5 were nearly full grown on April 30, with no indication of ova- ries, though with beginning egg-sac formation; two other individuals of those 17 Artemiz did not yet show, though ‘fall grown, any sexual differentiation. On May 10 I transferred from jar k those specimens which approached sexual maturity into a jar marked o, together with some unprepared fresh-water clay-mud. ‘These 14, in jar o transferred Artemia develop- ing into egg-bearing females, prospered well in the salt water of the new jar, and filled, as usual, their intestine with mud as if they had had ma- 30 H A466 GEOLOGICAL SURVEY OF THE TERRITORIES. rine mud. I had to take fresh-water mud because the marine mud be- gan to show signs of decomposition. On May 22 the four oldest individuals in jar o had brown eggs; also all the others attained maturity by May 29, so that I was sure that these 15 females would soon deposit for the first time their eggs. How many successive generations of Artemia salina retain the fac- ulty to reproduce parthenogenetically without males remains to be ex- amined. Joly made his observations with Artemiz from Southern France in 1840, and supposed that these Artemiz must be either her- maphroditic, or, if really males existed, that a single fertilization was sufficient for many generations. It would be of interest to re-examine the specimens of Artemize of the localities cited in literature of the years 1840, 1755 (Schlosser), 1830 (Thompson), 1851 (Leydig). Very likely the result would be that par- thenogenesis in Artemia often occurs. The examination of the ovaries and the occurrence of viviparous and oviparous individuals led me to the conclusion that oviposition appears in Artemia only when the egg-shell glands have so fully developed that the necessary quantity of congealing matter can be recreated, as only by this can the eggs obtain a solid, durable shell. Surrounded with such a shell the eggs obtain the power, hidden away in mud or even perfectly dried up, to endure the mest unfavorable external condi- tions and preserve the faculty of development after long periods of time. But if the development of the egg-shell glands has not been fully attained the conditions for the formation of a solid and durable shel! are wanting. The eggs of such Artemie then only receive a very thin egg skin, in consequence of which the favorable influences for the de- v elopment of the embryo will act upon the egg contents from outside, thus accelerating the embryo formation. C.—ON THE RELATION OF ARTEMIA SALINA MILNE-ED- WARDS TO ARTEMIA MUEHLHAUSENIT MILNE-ED- VARDS AND TO THE GENUS BRANCHIPUS SCHAF- FER. By W. J. SCHMANKEWITSCH.! {Translated by Dr. C. I*. Gissler. With Plate XXXIX.] In the session of the Neorussian Society of Naturalists at Odessa, held September 20, 1874, I made an addition concerning this matter to the observations made in former years, and now If have again to com- municate the following later results. I shall here briefly state that Artemia salina M. Edw. , Joly (Branchipus arietinus Grube var. Schman- kewitsch, Artemia arictina Fischer var. Schm.), a very variable form, yields not only by domestication but also in a state of nature even at a gradually increased concentration of the water, a form similar to Arte- mia muehlhausent Milne-Hdw., Fischer, which I had occasion to observe in the closed Kajalniker Salt Lake ee ian) near Odessa during the years 1871 to 1874, inclusive. In 1871, on the occasion of a great spring flood, the embankment which separated the lesser saline water of the upper portion of the Ku- jalniker Lake from the more saline portion of the lower part of the same lake broke, whereby the water of the latter became diluted to 8° Beaumé. At the same time Artemia salina appeared in great numbers, probably | Zeitschrift fiir wissensch. Zoologie, xxv, ltes Supplementheft, 1875. PACKARD. ] TRANSFORMATION OF ARTEMIA. 467% brought along with the flood from the upper portion as well as from the surrounding brine ditches near the same. After restoration of the embankment the density of the, water of the lower part rapidly increased, showing already in the summer of 1872 14°, in 1873 18°, at the beginning of August 1874, 23.59, and after a continued drought in September. of the same year | 25° of Beaumé’s areometer, at the latter time the lower part of the lake beginning to deposit salt. Simultaneously Artemia salina gradually degraded from eeneration to generation, so that toward the end of the summer of 1874 the majority of individuals were without furcal lobes, showing then all the specific characters of Artemia muehlhausenti (Fig. 6). In 1871 Artenvia salina, or better, one of its varieties, had moderately large furcal lobes, and on each of them eight to ten, seldom 15, sete, distributed over both sides and the tips (Fig. 1). In the successive generations in the beginning of the summer of 1872, these furcal lobes were already smaller, with but 3 to 5 or 3 to 4 seta, the salt water then showing 14° Beaumé (Plate XX XIX, Figs. 2 and 3). In the same season of 1873 and at 18° B. the furcal lobes were still smaller, representing short conical knobs with but one, two, seldom three, sete (Fig. 4). Toward the end of the summer of 1874, many individuals still possessed conical knobs or protuberances instead of furcal lobes, without or with but one seta on tip, but the majority of them were entirely destitute of fureai lobes and sete, as is the case in Artemia muehlhausentt with which these degraded examples were identical in their smaller size as well as in other characters (Figs. 5 and 6). J also obtained the same results by domesticating Artemia salina in salt water of gradually increased density or concentration, the examples obtained being identical with those from the Kujalinker Lake at the end of the summer of 1574 (Artemia muehlhausenti), yielding also the same transitory forms. : By a reverse treatment, 7. e., by gradually diluting the salt water, I succeeded with Artemia muehlhausenit in producing already, after sev- eral weeks, a furca in the form of conical knobs, with one terminal bristle, by which treatment also the development of other parts of the body assumed a direction toward the higher specialized varieties of Artemia salina, this being at. variance with the retrograde development taking place in condensing the salt water. It is remarkable that the gills of these animals enlarge in proportion or in ratio with the density. of the water, so that in the form without furcal knobs (Artemia muehlhausenii) the surface of the gills is much larger in proportion to the size of the body than in Artemia salina. The gills of the former especially enlarge in width. I draw the inference that as the water of higher density. contains less oxygen these Crusta- ceans adapt themselves by gradually enlarging the surface ot the breathing apparatus. Concerning the gills, I have to state that they are elongate in Artemia salina and oval in A. muehlhausenti (Figs. 7and 8). The width of the gills in A. salina average scarcely half of their length, in A. muehl- hausenti two-thirds of their length. As regards the length of the body, I may mention the following measurements, showing the proportionate sizes of the gills; In Artemia salina the average length of the gills at a density of 10° B. is the one- twenty-first part of the body length, the width being the one-thirty-ninth part of the same. In Artemia muehlhausenii the average length of the 468 GEOLOGICAL SURVEY OF THE TERRITORIES. gills at a density of 24° B. is one-eighteenth part; their width is the one-twenty-eighth part of the body length. In measuring the Artemia salina the furcal lobes were not counted in, which would have made the difference still greater, considering the larger bulk of the body of Artemia salina compared with A. muehl- hausentt. It appears that the species (Arten) of the genus Artemia are liable to undergo, also, progressive developments at a gradually lessened density of the salt water. The nature of those salt-water pools yields the con- ditions necessary for their progressive growth, which pools, after a number of years by continued washing of the briny soil, may turn into fresh-water pools. Indeed, Artemia salina inhabits, also, such salt-water pools in the neighborhood of the lake in which occurs, at a low density of the water, also Branchipus spinosus Grube; at a still lower density, Branchipus ferox Grube, and another species of Branchipus with hook- like bent furcal lobes, which latter species I described as Branchipus medius in the “Schriften der dritten Versammlung russischer Natur- forscher.” In artificially domesticating Artemia salina in gradually diluted salt water I obtained a form with the characters of the genus Branchipus, (B. Schaeffer) which might be regarded as a new species of Branchipus. I had already occasion to discuss this point in the *‘Schriften” of the Russian Naturalists, third session, and in the “ Schriften” of the Neo- russian Society of Naturalists (Vol. II, Bai 2), and again have to state as follows: The only two characters separating fie genus Branchipus from the genus Artemia are the following: Firstly, that Artemia, inclusive of the genital segment (two segments together), possesses eight apodous postabdominal “segments, with the last of these eight segments nearly twice as long as the penultimate (Ifig. 9c), while Branchipus has nine such segments, of which the neighboring segments, by twos, show but a small difference in length; and, secondly, the existence of a physiclogi- cal difference, parthenogenesis occurring in Artemia, which phenomenon has not yet been observed in Branchipus. This is a negative and ill- defined character. The first mark of distinction seems to be more important, but nnder- goes changes in Artemia under the influences of the surroundings, where the character of the genus Branchipus appears especially, than when several generations of Artemia are domesticated in gradually diluted salt water. I have convinced myself, that the last long eighth segment of the post- abdomen of Artemia is homologous with the two last segments of the post- abdomen in Branchipus, namely the eighth and ninth. In the progressive growth of several generations of Artemia in gradu- ally diluted salt water the last apodous eighth postabdominal segment of Artemia subdivides itself into two segments, whereby nine apodous segments are formed (Figs. 10e and d), as in Branchipus. Branchipus, however, in its youth and towards the end of its Jast larval state, has but eight abdominal segments, of which the last is also as long as in Artemia. Also without artificial domestication we can convince our- selves of the homology of the last eighth apodous segment of Artemia with the same two last apodous segments of Branchipus. In the species of Branchipus occurring in this region we find fine bristles distributed around the posterior end of each postabdominal segment, except in the last ninth segment. Every bristle arises from the mid- dle of a complex of small tooth-like spines which are of extraordinary PACKARD. ] TRANSFORMATION OF ARTEMIA. 469 size in the male of Branchipus spinosus. Such bristles we also find in Artemia in the same places and similarly distributed (lig. 9d), only that they do not arise out of a complex of dentate spines, but out of the middle of a complex of cuticular cells, which can scarcely be distin- tinguished from the surrounding tissue (Fig. 11). It is of some importance that in Artemia not only near the end of each segment do we find such circularly placed bristles, but also in or a little above the middle of the last long eighth postabdominal segment, 4. @., on that spot where the articulation ought to be, and where it is actually found in Branchipus, between the eighth and ninth segment, and where in Artemia this articulation after domestication of several gener- ations in salt water of successive lower density, @. e., under such con- ditions, is formed, which may be serviceable to progressive develop- ment.! Under the same conditions the complexes of cuticular cells just men- tioned transform; out of their midst bristles develop by degrees in both sexes of the domesticated Artemiz, into complexes of denticular spines, as they are found in both sexes of Branchipus. (Fig. 12.) These denticular spines are small and of equal size in both sexes of Branchipus ferox ; in the female of B. spinosus they are also smak, but in the males of extraordinary size; in Branchipus medius (described else- where) they are large in both sexes, somewhat larger however in females than in inales. At the same time, in domesticating Artemia, all other characters change progressively toward Branchipus; as, for instance, the length of the furcal lobes, the number of their bristles, and so forth. After such results we unwillingly arrive at the conclusion that the Artemia usually occurring in salt water of great density is nothing else than a degraded form of Branchipus under the influence of its surround- ings, which latter form usually inhabits fresh water or salt water of low density. On the other hand we have in Branchipus a higher developed form of Artemia, which has transformed in a progressive direction. The cause of this may not only be the different concentration of the water, but also its temperature. In nature Artemi@ mostly inhabiting salt lakes represent the summer forms, while Branchipus, otten populat- ing dried-up pools, represents the spring or fall form. in domesticating, L observed that a high density of the water retains the growth and the development of specific characters of these animals, while a simultaneous higher temperature evokes sexual maturity earlier than the complete development of limbs; higher temperature together with higher density of the salt water also contribute to retrogradation of forms and their degeneration. Of course, as I convinced myself, a gradually increased density of the Salt water, even at a lower temperature, tends to degradation of forms; for such a water, besides its mechanical influences upon the organism, contains less oxygen than less saline water and much less than fresh water, which plainly shows itself in artificially domesticating these animals, and which point I have already referred to. The following are the principal results of my investigations: 1. In artificial domestication of several successive generations of Ar- temia salina Milne Edw. in salt water of gradually increased density we obtain a form identical with Artemia muehlhausenti M. Edw. 2. Artemia salina M. Edw. is also apt in a state of nature after a 1 See Plate II of the “Schriften” of the third meeting of Russian N aturalists, ‘Loo- logical Part. A470 GEOLOGICAL SURVEY OF THE TERRITORIES. small number of years, and a comparatively short series of generations, in a salt lake with inereased density to transform itself into a form identical with Artemia muehlhausenti M. Kdw., whereby this form is enabled to remain constant, as long as the surroundings are not changed. 3. Artemia is apt, in artificially domesticating several generations in salt water of gradually decreased density, to progressively develop towards the genus Branchipus, obtaining thereby its generic characters, nine apodous segments. 4. In a state of nature salt-water ditches of different density, inhab- ited also by the higher specialized forms of Artemia, yield the condi- tions for progressive development of Artemia into Branchipus. 5. The size of the fureal lobes in Artemia, the number of bristles and their distribution on the tips and sides of the lobes, are, together with the other generic characters, dependeat on the concentration of the salt water inhabited by Artemia. 6. At a lower density of the salt water occur also in certain brine ditches Artemie with pretty long turcal lobes, with a considerable num- ber of bris(les (up to 22 distr ibuted over each lobe), similar to Branchipus. 7. The only characteristic features distinguishing the genus Branchi- pus from the genus Artemia are: Firstly, the presence of eight apodous postabdominal segments, whereby the last eighth segmentis nearly twice as long as the preceding, while in Branchipus there are nine such apodous segments, of which neighboring segments, by twos, show but a trifling longitudinal differ- ence. Secondly, parthenogenesis occurs in Artemia, while in Branchipus it is not vet known to oceur. 8. The last long eighth postabdominal segment of Artemia is homol- ogous with the last two postabdominal segments ot Branchipus. T have now to append a few words on the parthenogenetic propaga- tion of our Artemia. I had already observed parthenogenesis in Artemia in 1871, while ar- tificially domesticating several isolated generations. It being something new to me at that time, I devoted more attention to investigations on the influence of surroundings on Artemia relative to morphology. Of three isolated generations of @ Artemia salina 1 obtained, while artificially domesticating them, by parthenogenetical propagation, in every density of the salt water that sustained their life, only females. . . . [mentioned in the “Schriften” of the third meeting of Rus- sian naturalists at Kiew, . . . that the males appear in the lake in great numbers at a moderate density of the salt water. For such moderate density I took the density of the Hadsehibei Lake in the summer of 1870, 1t having been literally filled with Artemia, whence they were thrown on the shores in piles by the waves, where they decayed. However, f committed a mistake, overlooking an error in the protocol of the third meeting at Kiew, having said in my printed report that only at a mean (moderate?) density of the water, similar to the density of the preceding year (1870), by domestication as well as during the summer in the lake males appear, instead of having said, only at a moderate density of the water, similar to that of the preceding year, by domesti- cation as well as during the summer in the lake the males ought to ap- pear. As I noticed at the time, that the males of Artemia appear in the Jake at a certain density of the water, I assumed, aiter I could not ob- tain them either at a higher or lower density, that they still ought to make their appearance at the density for which I took the salt water in the PACKARD. ] TRANSFORMATION OF ARTEMIA. 471 summer of 1870, then not yet being aware that, according to Professor Siebold’s investigations, no males could be developed! The same error crept into an extract of the protocol, sessions of the zoological part of the third meeting of Russian naturalists at Kiew contained 1 in this journal (Zeitsch. f. w. Zoologie), and this gave Professor von Siebold occasion for a timely remark.? Taking advantage of the present occasion to correct the mistake, observing that if was not printed in my paper, although the latter, together with the report, was prepared in the same session, I have yet to. add that Artemia salina becomes accustomed to gri dual changes in the concentration of salt water in the lake, as well as in do- mesticating them, and then becomes fitted to stand a very high or very low density of the water, so that either of them form a suitable envi- ronment. In rapidly changing the concentration of the salt water the same is rendered unfit to sustain life, changing the manner of obtaining food, and produces, at the same time, in a state of nature, the appear- ance of males in forms to which parthenogenesis is peculiar. I had already observed this in Artemia in the lake, but saw this es- pecially in Daphnia with artificial domestication of non-isolated females, that the males of the domesticated species first appear on the most ex- treme life-sustainable limits of the surrounding elements, 7. ¢., as well at a too low as at a too high temperature. If we domesticate the fresh-water species, Daphnia magna Leydig, in weak salt water, which they stand well, there appear, at this compara- tively rapid heightening of density of the salt water, males and fertil- ized eges at such a moderate temperature, at which ordinarily the same species in fresh water propagates parthenogenetically. In the Hadschibei Lake occurs Daphnia rectirostris Leydig, at a den- sity of the salt water of 5° to 8° B., especially in spring and fall; the Same disappearing in summer at a higher density of the salt lake, while before the females often in the middle of the summer cease to pro- pagate parthenogenetically, bearing as in fall fecundated eggs in ephippia. Altogether I produced during the artificial domestication of Daphnia the appearance of males and fecundated eggs through rapid augmenta- tion of the density of the salt water as well as through rapid increase of temperature. However it is difficult to say which will be the mean of concentration for a known species of Artemia, because a slightly less- ened density, though-favorable for the growth of the individual, weakens its power ct propagation, while a heightened density augments (or sup- ports) propagation, on the other hand this being a hindrance for the development of the individuals. The undiscovered mean of density, it seems to me, must be between these two points, the most extreme limits of the favorable condition of the surrounding elements being then out- side of those two points. On these limits we must find a density at which the males appear in the lake in great multitudes, as severel observations and analogous in- vestigations on Daphnia have demonstrated. I therefore recede from my opinion that the males of Artemia appear at a mean density of the salt water, if the mean density is determined between that of favoring the development and that of assisting the pro- pagation. Until now I have found the greatest number of males of Artemia sa- lina in the Hadschibei Lake in the middle of the summer of 1870, at a 1C. von Siebold, Beitriige zur Parthenogenesis der Arthropeden. 1871, p. 224. 2C. von Siebold, Ueber ‘Parthenogenesis der Art. salina. Extract of ‘the sessions of the Royal Academy of Sciences at Miinchen, 1873, p. 190. 472 GEOLOGICAL SURVEY OF THE TERRITORIES. strong evaporation after continued drought, the salt water then rapidly reaching a high concentration. I have yet to add afew words on the geographical position of the lake and the salt-water ditches inhabited by Artemia salina. Two great salt lakes, the Hadschibei and the Kujalnitzky, are situated about 7 or 9 versts from Odessa towards Nikolajeff. These two lakes (Russian, limane) were formerly two broad river entrances and ocean bays, into which two rivers formerly poured. At present these two small draining rivers no more deserve their names. The ‘‘limanes” were subsequently cut off from the sea by broad stretches of sand, the Peresippe, and were transformed into salt lakes. Only in the lower part of the Kujalniker-Limane, separated by an artificial embankment from the upper part for the purpose of obtaining salt, is the salt deposited. The Hadschibei-Limane showed with my areometer 5° B. as the low- est and 12° B. as the highest concentration. The salt-water ditches are distributed over the saline soil in the neigh- borhood of the lake, situated between the lakes and the seashore along the Peresippe to near the city of Odessa. In the various ditches occurs salt water of various densities from nearly fresh water up to water of 5° Beaumé. Only the more salty ditches of 4° to 5° B. are inhabited by a (ziem- lich ausgebildet) developed form of Artemia salina, often associated with Branchipus spinosus. In less saline ditches occurs Branchipus ferox and Branchipus medius. Similar results, as regards the evolution of the form, I have also obtained from Daphnia, Oy clops, and Canthocamptus, and I promise to soon publish these investigations. REMARKS.—1. I have especially endeavored in the above writings to draw attention to the fact that in domesticating Artemia salina in gradually diluted salt water, after several generations and at a pro- gressive development, I obtained a form presenting the most important, morphological characters of the genus Branchipus, so that such a form was at one time regarded by me as a new species of Branchipus. The principal generic characters of. Branchipus I regard as the nine apodous postabdominal segments. Although we obtain in progressively domesticating Artemiw the characters of the genus Branchipus, and although, also, the other char- acters change in the direction toward Branchipus, such an artificially domesticated Artemia, for many reasons and marks of distinction, can only be considered as a lower form of a Branchipus, representing, con- sequently, a transitory form from Artemia toward Branchipus, and an intermediate form between these two genera. Such a form can also be looked at as a prototype or radical type of these two genera. 2, An important circumstance is that in those Branchipus observed by me, a few bristles are distributed in a circle around each post- abdominal segment just before the articulation, and that in Artemia such bristles occur also in a circle at a little above the middle of the last postabdominal segment. I mentioned above that in Branchipus each such bristle arises out of the middle of a complex of dentate spines, which are of very large size in the male of Branchipus spinosus. I find it necessary to add that I found such dentate spines in both sexes of the species of Branchipus examined by me only on the ventral side of the postabdomina! segment just before the articulation, at which location they could be plainly seen. It is weil known that in the male PACKARD. ] TRANSFORMATION OF ARTEMIA. A738 of Branchipus spinosus groups of dentate spines occur only on the ventral side of the postabdomen just before the articulation. In the same places fine bristles arise out of groups of circulatory cells in Artemic living in salt water of high density, which cells, by domes- tication of several generations of Artemia in gradually diluted salt water, transform into groups of small dentate spines. 3. Under the name of postabdomen I mean the last nine segments of the pesterior section of the body, or all apodous segments which are frequently called postabdomen. Artemia has eight such segments. After all, it seems to me that not all apodous segments deserve either the term abdomen or postabdomen, since the first two segments, bearing the external genital organs, are more sharply defined or insected from the following segments, being also somewhat shorter and broader than the latter, having therefore more resemblance with the precediug limb-bearing segments, It appears to be more proper to add the two connate genital seg- ments to the preabdomen, calling postabdomen all the other apodous segments; this view concurring ‘also with the developmental history. According to the latter view we have seven apodous segments in Branchipus and six in Artemia. D.—CONTRIBUTION TO A KNOWLEDGE OF THE INFLUENCE OF EXTERNAL CONDITIONS OF LIFE UPON TUE OR- GANIZATION OF ANIMALS. By WLADIMIR SCHMANKEWITSCH.! {Translated by Dr. C. F. Gissler.] I published in 1875 in the Russian language, in the Transactions of the Neo-Russian Society of Naturalists (Vol. III, 2d part), a paper under the title ‘‘Some Crustaceans of the salt and fresh water s, and their rela- tion to the surrounding elements.” ? After the further elaboration of the material, I shall publish the entire contents of my labors, at present submitting only the part which I re- gard as the more complete. I.—Some instances illustrating the influence of salt-lake surroundings upon the life and development of several crustaceans. 1 Zeitschrift fiir Wissenschaftliche Zoologie, XXIX, 429-494, 1877. 2 The contents of the paper are the following: Chapter I. The genus Cyclops (€. bicus- pidatus Cls. and C. odessanus n. sp.. C. brevicaudatus Cls., C. brericornis Cls., C. serrulatus Fischer. C. tenuiformis Cls., C. minutus Cls.). Enumeration of the species and races of this genus from the neighborhooa of Odessa. Diagnosis of the undescribed forms of Cyclops. The indication of forms necessary to compare the characters of the known species of this genus. General remarks on Cyclops brevicornis and C. brevicaudatus. Effect of the surrounding element upon the forms of Cyclops under artificial domesti- cation. Chapter IJ. Cletocamptus genus novum (family of Harpactidee), Cl. strémit and Cl. retrogressus, and domestication of the latter in changed surroundings. Chap- ter III. Transfuga gen. novum (fam. Harpactide), Tr. salinus n. sp., and Tr. lacustris n. sp. Chapter IV. The relations between marine forms and fresh-water forms in the family of Harpactidee. Chapter V. The genus Daphnia. D. magna Leyd. varietas, D. rectirostris Leydig ( Moina rectirostris Baird) of salt and fresh waters. Daphnia degenerata n. sp. and D. rudis n. sp., both marine forms. Chapter VI. The genera Artemia and Branchipus. Artemia salina Milne-Edwards. The generations of Artemia salina receiv- ing the characters of Art. Milkausentit. Branchipus ferox Chyzer varietas. Branchipus spinosus Milne-Edw. Branchipus medius mihi. The characters of the genera Artemia and Branchipus. The transformations of the branchial sacs and posterior gill-lobes in Artemia and Branchipus under the infiuence of the surroundings. A474. GEOLOGICAL SURVEY OF THE TERRITORIES. For the purpose of illustrating this, | have chosen Daphiia rectirostris Leydig (Moina rectirostris Baird) and Branchipus ferox Chyzer. Daphnia rectirostris occurs here in large numbers in fresh-water basins, brine ditches, and also in the Chadschibaisky Salt Lake. In the latter they occurred at a concentration of from five to eight degrees of Beaumé’s areometer. ‘Two characters are seen in the Daphnia rectiros- tris living in so diversified elements, the former depending on the latter. It appears firstly, that in salt water, and especially in the more saline Chadschibai Lake the middle temperature is lower, ¢. e.. the temperature more favorable for the life of Daphnia rectirostris than the temperature favoring the life of the same Daphnia in fresh water, so that the Daph- nia, being in reality a summer form of the fresh waters, changes in salt water into a fall form, occurring till the beginning of winter in the salt lake at a concentration of 7° to 8° Beaumé in immense quantities, even remaining viviparous at a temperature at which the individuals of the fresh-water generations of the same species could live no longer. Sec- ondly, the individuals of the salt-iake generations of Daphnia rectirostris represent a degraded or retrograde form of the fresh-water generations of the same species, differing from the latter the more the higher the conceniration of the salt-water basins in which they occur increases, so that the individuals of the salt lake difter more from the fresh-water ‘forms than the individuals living in salt ditches. So much do the forms of Daphnia rectirosiris from the salt lake differ from those of the fresh waters that they could be regarded as a separate variety of Daphnia rectirostris, althou gh it is but a transformed gener- ation retarded in its development, and changed under the influence of the surroundings of Daphnia rectirostris inhabiting the fresh waters. On account of various observations and experiments, I presume that the peculiarities of the salt-lake form of Daphnia rectirostris are entirely dependent on the properties of the salt water which they inhabit. Daphnia rectirostris cannot stand in summer a density of the water of the salt lake of 6° B., while it lives in great quantities in the same salt lake at a density of 8° B. in the fall, ‘toward the end of October and in November, being than viviparous, that is, at such a season in which the fresh- water form of our Daphnia has alre eady ceased to live. This is not an extraordinary phenomenon, considering that a certain aeration of the water is unconditionally necessary to sustain the life of Daphnia rectirostris, and that it is unimportant by which means the aeration of the water is regulated. Agreeing with the physical law the less the aeration of the salt water, the higher its density becomes, which results that fresh water must contain more air than any salt water of the same temperature. It consequently follows that also in a salt water of certain concentration at a corresponding lower tem- perature the same quantity of air as in fresh water could be contained. It is obvious that the quantity of air in the water of the Chadschibai Lake toward the end of October and at a density of 8° B. could approxi- mately be the same as that in fresh water during the summer, and therefore the processes of nutrition in the organism of Daphiia rectiros- tris could in reality be as favorable in both the fresh and salt water. Though analogous in general, they ditfer singly from each other, as, for instance, by the higher pr essure of the more dense water, which density again depends on the quantity of salt and the lower temperature of the water. Dependant on such differences between salt and fresh water are also partly some differences in the organization of the eal and fresh water forms of Daphnia rectirostris. In the females of the Chadschibai Lake, the penicilli or fascicles of PACKARD. ] TRANSFORMATION OF ARTEMIA. A475 knobbed setz (Tast-borsten) are but little developed, being scarcely fitty times shorter than the antenne themselves, while in the females of the fresh water the same sensitive penicilli are moderately long, and only six times shorter than the entire antenna. In the males, the sen- sitive bacilli are also shorter than in those males inhabiting fresh water. The small hooks situated near the sensitive bacilli on the tips of the male antenne of fresh water are strongly curved with pointed tips, while in the males of the Chadschibai Lake those hooks are shorter, less curved, and with blunt tips. Of the two pointed pale sensory threads situated on geniculated protuberances of the first posterior third section of the male antenne, the posterior one is a little shorter than the anterior thread, the latter coming out a little more in front. These threads are in the males of Daphnia rectirostris of the Chadschi- bai Lake, not in a straight, but in a screw-like line. The distance between one thread and the other is considerable, which character in the fresh-water males is much'less prominent. The fresh-water individ- uals of this species have in their earlier stages a period during which they resemble in this, as well as in other respects, the mature forms of the salt lake. Besides the differences observed in the antenne of the salt-water generations of Daphnia rectirostris, our attention is called to the num- ber of slender ‘gefiederten,” or, better, finely toothed spines, which occur on the lateral surface of the postabdomen of Daphnia rectirostris, running laterally seriatim and nearly parallel with the direction of the rectum. Leydig! called them finely feathered spines, which I would have called triangular, laterally finely dentate plates. However this may be, we observe in our fresh-water forms of D. rectirostris on each side 11 to 13 of these spines or plates, only 7 to 9 in the salt-lake form, meaning here, as a matter of course, mature individuals only. In younger specimens there are less spines than in the adults of the same surroundings, and therefore the young fresh-water forms have the same number of spines at a certain age as the adult forms of the Chadschibai Lake, which demonstrates the retarded development of the latter. Furthermore, our fresh-water Daphnie (D. rectirostris) are nearly color- less, or of a slight yellowish color, while the same species in the salt lake are of a reddish color. The so-called winter eges of the former have an ochreous or orange-colored yolk. Those of the latter are red throughout. The bristles in general are less numerous in the salt-lake form of the Daphnia than in the fresh-water form, and the average size of body in the latter is also less than in the former, although the differ- ence is but slight. | The generations of D. rectirostris inhabiting our salt ditches repre- sent in every respect a transitory form between the fresh-water form and the salt-lake form, which lake has a higher density of the salt water than the water in the salt ditches, where it fluctuates between 1° and 5° Beaumé. In domesticating Daphnia rectirostris I also convinced myself that the salt-lake form can also live at a lower concentration of the salt water, only requiring herein a higher temperature, than that fit for them in the very saline lake; that is, it wants a summer but no fall temperature. In this less concentrated salt water the degradation of individuals is considerably diminished with the generations, so that they finally resemble the individuals of this species from salt ditches, i. e., they approximate the fresh-water form. In so domesticating, 1 Naturgeschichte der Daphniden, Leipzig, 1860, p. 175, Tab. X, 76. 476 GEOLOGICAL SURVEY OF THE TERRITORIES. during a rather brief duration the sensory threads on the tips of the antenne become nearly three times longer than before the beginning of domestication. We now find in comparing the fresh-water generations with the salt- water generations of Daphnia rectirostris that the latter generations not only changed in consequence of the immediate effect of the surrounding elements, but also in consequence of retarded development under their influence; and, furthermore, that the sexual. maturity shows itseif earlier in the salt-water generations than the complete typical development of the body parts. The termination of the sensory antenna, the color of the body, the lesser pinnulation of the bristles in the salt-water genera- tions are principally dependent upon the immediate effect of the sur- rounding elements. The smaller number of the above-mentioned spines on the postabdomen principally depends upon the retarded develop- ment under the influence of changed surroundings. In the latter case the individuals commence, without awaiting the development of their body parts, to augment, and are in that state a complete animal form. Branchipus ferox affords a still more characteristic example of the in- fluence of the salt-lake element. Milne-Edwards,! whose words Grube? repeated in his diagnosis of this species, gives a brief description of Branchipus ferox from the neighborhood of Odessa. Chyzer*® completed his description from Hungarian specimens. The diagnosis by Chyzer of this species differs so much from that of Milne-KMdwards that both authors could not possibly have had one and the same form of Branchi- pus, as we shall see later on. It is difficult to understand why Milne- Edwards does not mention the two so important characters of this species, which ought to rank with the principal characters which Chyzer enumerates. This is the conspicuous length of the egg-sac, and espe- cially the iact that the abdominal appendages or fureal lobes are bristled only on their inner edge. To this latter peculiarity Chyzer especially points out the characteristics of Branchipus ferox. It is evident that Milne-Edwards had a very closely allied form to that of Chyzer’s, since in the neighborhood of Odessa, wherefrom Milne-Edwards’s form came, generations of this species occur in salt, brackish, and fresh water, which, owing to their dependence of the density of the water basins, consider- ably differ in their characters. The generations inhabiting salt-water ditches of about 5° Beaumé differ as much from the individuals inhab- iting fresh water, especially the Hungarian forms deseribed by Chyzer, as any species will differ from another one. Had I not found all pos- sible transitory forms between fresh-water and salt-ditch forms, had I not convinced myself of the variability by domestication of this form, J should have regarded the salt-lake specimens as a new form. Tor some time I really took them for a variety of Branchipus ferox Chyzer. At present, and after So many convincing results, I can only condition- ally regard this form as a variety. To demonstrate how much the salt-lake generations of Branchipus ferox (from the salt-water ditches) differ from the Hungarian fresh- water Specimens, compare the following characters: The egg-sac of the salt-lake Branchipus ferox reaches in its length only to the beginning, or to the middle, of the fifth apodous segments, but as the following sixth, seventh and eighth segments are longer than the anterior seg- ments, the egg-sac reaches scarcely to the middle of the postabdomen, 1H:stoire naturelle des Crustacées, III p. 369. 2Bemerkungen tiber die Phyllopoden, Archiv f. Naturg p. 142, 1853. 3Nauna Ungarns Crustaceen. Verhandl. der zoologisch-botanischen Gesellschaft in Wien, 1858, p. 516. PACKARD.] TRANSFORMATION OF ARTEMIA. AGT counting in all apodous segments, while in the Hungarian forms the length of the egg-sac equals the whole postabdomen, excluding the ab- dominal appendages. Besides, in Branchipus ferovw of the salt-water ditches the egg-sac is not spindle-shaped, only elongate, often entirely oval, 7. e., not only shorter, but also broader, as in the form diagnosed by Chyzer. In our salt-water ditch forms the furcal lobes average in length the eighth part of the body length, inclusive of the furcal lobes; in Chyzer’s Hungarian form, as shown by the measurements, the fureal lobes average the fourth and a half part of the whole body length in- cluding them, that is, they are much longer in the Hungarian form. The most important difference consists in that while in Branchipus ferox of our salt ditches the fureal lobes have both edges bristled, in the form described by Chyzer only the inner edges of the lobes are bristled. Lastly, our salt-water ditch form measures, inclusive of the abdominal lobes, seventeen to twenty-two millimeters, the Hungarian form twenty- nine to thirty-four millimeters. Our salt-water form approaches in all other respects the diagnosis of Chyzer, and does not disagree with the determinations of Milne-Edwards and Grube. Besides the difference between the specimens of our salt-lake-water and the Hungarian fresh-water forms of Branchipus ferox, we find, after Strict examination of the matter, that the bristles of the fureal lobes in our Salt-water-ditch forms, only in young animals shortly before becom- ing sexually mature, commence at the base of the lobes in one height, and that on getting older the number of bristles is lessened along the exterior edge, and that in the adult, and especially in old individuals, the bristles on the exterior edge of the furcal lobes will be seen to com- mence more than twice lower than on the inner edge of the same. At a length of the fureal lobes of 2.5™™, in the adult form, the bristles be- gin on the inner edge at a distance of 0.24™™ from the base of each lobe, but on the exterior edge they begin at a distance of 0.52™™ from the base of each lobe. The bristles on the exterior edge of the lobes are in adults of this form more than twice shorter than those on the opposite inner edge, especially on the first half of the fureal lobes. The younger the individuals are the more trifling is the difference between the bristles of the inner and outer edge of the lobes. Yurthermore, in the salt-water ditches of low density such generations of Branchipus ferox live, whose individ- uals have an average size of about 22™, In these larger specimens the exterior edge of this or that abdominal appendage in the adult state has no bristles from base to the middle of the lobes. The bristles of the exterior edge are also shorter and more sparsely distributed than in the preceding form. Their egg-sac usually reaches down to the middle of the fifth apodous segment, and is a little longer than the egg- sac of the preceding form. ‘The ditches with nearly fresh, scarcely saline-tasting, water harbor also still larger specimens of Branchipus ferox, measuring some 25"™ in average length. In these large individ- uals in mature age the exterior edge of either furcal lobe is without bristles from base down to over the middle of each lobe. The remain- ing bristles are again still more sparsely placed, and also shorter than in the preceding form; the egg-sac is also a little longer. Specimens of Branchipus ferox, collected by me in ditches on Taman Island, in the neighborhood of the city of Kertsch, represent another link in the series of transitory forms between the extreme generations of the salt-lake and Hungarian fresh-water specimens. In the Taman specimens, which have a length of 50™", the egg-sac reaches to the middle or to the end of the fifth apodous segment of the abdomen, the fureal lobes having nearly the same length as those of the Hungarian 478 GEOLOGICAL SURVEY OF THE TERRITORIES. specimens; but in the adult state, on their exterior ‘terminus of the lobes, remain more or Jess short, sparsely placed bristles, the less the older the specimens are. As the smallest number of bristles, 1 found seven; so that at 6.9"" length of a lobe its exterior margin was bristled only up to a distance of 1.5™". As the highest number of bristles in mature specimens, I counted fifteen; so that at 6.8"" length of a lobe its exterior margin was bristled up to a distance of 3.4" from the tip of the lobe. To explain the formation of such a remarkable character as the miss- ing of bristles on the exterior margin of the furcal lobes im generations of Branchipus ferox inhabiting fresh-water ditches, we need only be reminded that these lobes are the longer the less dense the water is in which they live, and that in the real fresh-water generations of this species the furcal lobes are the largest. I have also observed that these lobes distend at a wide angle in swimming; the wider they distend the longer they are. In addition, the exterior margin of these lobes contin- ually cut the water, being therefore in a higher degree, subject to the mechanical influence of the water. Even if the pressure of the salt- water be higher then are the furcal lobes of the salt-water forms of this species much shorter, and, besides, we may say that the salt-lake gen- erations do not fully grow up; therefore, remaining provided with the principal characters of the young fresh-water forms. The fresh-water generations of Branchipus ferox have, amongst all European-_species of Branchipus, the longest fureal lobes. The domestication of several generations of this species in sait water of various concentration verifies also the effect of the surroundings. I therefore can see no necessity of admitting here an influence of nat- ural selection and to add new unknown factors to solve this problem. One of the most remarkable phenomena is the fact that in our shallow marine district so rich in salt-water basins (closed lakes and salt-water ditches), even in pure fresh water the typical fresh-water form of Bran- chipus ferox Chyzer does not occur, but only a form approximating in a certain degree those of the lowest generations of this species, inhabiting our salt-water ditches, connecting it with the Artemia; above all with the extreme race of Artemia salina (varietas a), which also lives in our salt-water ditches. This is not the only example of such an abberration of form. In the fresh waters of the neighborhood of Odessa we do not find the real Daphnia magna Leydig; however, one of its races occurs, representing an abberration toward Daphnia pulex Leydig! of a lower erade. The generations of our fresh-water Daphnia magna variety, distribute themselves also in a few salt citches, where they form a still greater deviation from the typical form. In more saline ditches (of about 3° Beaumé) oceur such forms of Daphnia, bearing the characters of another, simultaneously reminding one of Daphnia magna varietas, D. pulex, and partly also of Daphnia reticulata and D. quadrangulata Leydig. I described this form under the name of Daphnia deqgenerata? j - Regarding it as a degraded form of those ancestors, which gave origin to the existence of Daphnia magna and PDP. pulex, I actually convinced myself in examining generations of Daphnia degenerata at difterent seasons of the year and at various densities of the salt water, and also, by domesticating them, that it is a changed and degraded form of our 1 See my reports in the ‘‘Schriften” of the Neorussian Society of Naturalists, Vol. II, Part 2, pp. 196-216. 2 Opus citatum, pp. 228-232. I have to add the following: The sensory antenna of the female of D. degenerata is provided on its upper surface with the same bristle as occurs in D. magna. PACKARD. ] TRANSFORMATION OF ARTEMIA. AT9 variety of Daphnia magna, the latter variety being itself again an inter mediate form between the typical Daphnia magna and D. pulex. If we would restore the middie radical form, which gave origin to Daphnia magna and D. pulex, we would receive a form most similar to our Daph- nia magna varietas, in the production of a still farther allied, a prototype for the largest number of Daphniz, we would arrive at a form most similar to Daphnia degenerata from the salt-water ditches. Such ex- amples show that, owing to the neighborhood of salt waters in which the generations of the fresh-water species distribute themselves and in which they change under retardation of development, the species them- selves in fresh waters of such districts deviate to a certain degree jrom the typical form, t. e., they change toward the direction of the next lowest species of their genus. In consequence of the existence of such an ele- ment in these districts the area of distribution of the species changes; but as the center of this area will be found somewhere between the fresh-water and the salt-lake e'ement, the aberration of the fresh-water generations in the neighborhood of salt-lake waters, in which the gene- rations of the fresh-waters pecies already considerably changed them- selves and become retarded in their development, is easily understood. The salt ditches, which distribute themselves on saline soil near Odessa between the sea and the two salt lakes, the Chadschibaisky and the Ku- ‘jalnitzky, become fresh-water ditches after gradual elevation, and sim- ultaneously begin to become populated with fresh-water generations, whereby these generations form, to a certain degree, changeable transi- tions toward the more changed salt-lake forms. Some of the ditches six years ago containing salt water of about 3° to 4° Beaumé, and inhabited by the salt-water species, Branchipus spinosus Milne Edw., now contain nearly fresh water, and are populated this year (1876) with the fresh- water forms Daphnia magna Leydig varietas and Cyclops brevicaudatus Claus, slightly changed in the direction toward the lower forms. In re- lation to the latter, a transitory form of Cyclops brevicaudatus varietas b' and Cyclops brevicaudatus Claus, was to me of great interest. In the real fresh-water Cyclops brevicaudatus the extreme inner one of the four furcal bristles is twice as long as the extreme outer, or actually the twenty- fifth part shorter than the double length of the last outer bristle; in gener- ations inhabiting less saline ditches the extreme inner bristle is, on an average, the sixth part shorter than the double length of the extreme outer. In Cyclops brevicaudatus varictas b. the extreme inner fureal bristle is but little (one-quarter) longer than the extreme outer. The adult forms of the changed generations of Cyclops brevicaudatus in the less salty ditches exhibit nearly the same relation of body parts, as seen in the young, immature, pure fresh-water forms of the same species; but the ma- ture individuals of said variety correspond in this point with the younger indiwiduals of the species. To this I have to refer also the interesting influence of the surround- ings upon the development of specimens of Artemia. The growth of the specimens of Artemia salina in salt water of high density and at the same temperature proceeds at least twice as slow as the growth of speci- mens of Branchipus ferox in less saline water. Abstractedly from the fact that the growth of specimens of Artemia salina requires much time, sexual maturity appears much earlier in proportion to the full de- velopment of body-parts, than in Branchipus. At a high concentration 1Consult my paper in the “Schriiten” of the Neoruss. Soc. of Naturalists, vol. 11. part 2, pp. 32 to 36, and 74 to 77. Also on the domestication of Cyclopide, ibidem, pp. 84 to 95. A480 GEOLOGICAL SURVEY OF THE TERRITORIES. of the salt water, only inhabitable by Artemia, and especially at suffi cient warmth, the mature sexual products show themselves already at a time when the provisional parts of the second, lower antennz were scarcely dropped, ¢. e., when they have not yet left the last larval stage. Artemia lives a much longer time in the larval state than Branchipus, indeed the longer, the higher the concentration of the water for Artemia and the lower for Branchipus. Between the fresh-water Branchipide and those Artemice which can still live in a salt-lake self-depositing salt, there is a relative great difference. Accordingly we must allow that we can produce, by corresponding domestication of generations of Arte- mice, already in their larval stage, but in any case in the last period of the latter, before the second antennew have dropped their provisional parts, sexual maturity. Carl Vogt’s observations have shown that the eyes appear much later in Artemia than in Branchipus,' and I presume that this is applicable to those Artemiz which are in relation to Bran- chipides, degraded forms of the latter. I have to mention the circumstance that the concentration of the salt water vigorously stimulates the multiplication of Artemia. The highest increase of a given species of Artemia is brought about by a density of the salt water which is a little higher than that generally assumed as the mean for this species; therefore under such conditions which hin- der, to a certain degree, the growth of the individuals and the develop- ment of their body-parts. Cn the other hand the most rapid growth and the progressive development of body-parts happen to appear at such a concentration of the salt water, which is a little below the mean for a given species, and at which density the propagation of the indi- viduals decreases. In Artemia salina I observed the highest multipli- cation in a state of nature ata density of the salt water of 10° to 12° Beaumé’s areometer and with summer temperature; the highest devel- opments of body-parts I noted at 5° to 79 Beaumé, and at the same tem- perature. Between these limits must be the mean density of the salt water for our Artemia salina; Ihave also to remark, that the density of the salt water, together with the temperature, and independently of the same, influences the growth and the propagation of these animals. It appears that the parthenogenetic reproduction in Artemia does not only depend upon the temperature, as in Daphnia, but also upon the density of the salt water. I observed at least viviparous reproduction in Ar- temia salina in stronger saline water at such a low temperature at which viviparturition in the same species does not occur in less saline water, although it does not hinder viviparturition at a comparatively higher temperature. In all such cases the quantity of air contained in the water and dependent upon temperature, as well as upon concentration of the salt water, plays an important role, regulating many of the fune- tions of life. Perhaps the variability of the concentration of the salt water yields, in Artemia, one of the main causes of parthenogenesis, the latter not being yet known to occur in Branchipodide, inhabiting prin- cipally fresh water. Density and temperature of the salt water in their influence upon Artemia are combined in such a manner that, when the existence of an Artemia-like form in fresh water is possible, the same can only exist at a nearly summer and possibly high temperature. The lower the density of the salt water the higher a temperature is re- quired, if Artemia shall preserve its form at least in its principal char- acters. In this sense, Branchipus stagnalis, which, according to the - 1“ Revue scientifique de la France et de l’étrang.,” 2. series, 1873, No. 27, pp. 632 to 633. Also in ‘‘ Meeting of Swiss Naturalists” in Freiburg 1. s., 1872. Sage TRANSFORMATION OF ARTEMIA. A81 statements of the authors (Leydig, Claus, Spangenberg) has eight apo- dous segments of the abdomen, represents in its principal characters an Artemia-like form; however, it remains to be determined whether this species is peculiar to summer temperature, of which we have a few inti- mations. It seems that the dependence of the quantity of air in the salt water upon its density, beside the mechanical effect of such a water, forms one of the main factors of the sexual and specific characters of Artemia, whose forms are distributed according to the various densities of the salt water, as the species of a known genus are dispersed ac- cording to geographical latitudes, or also after their appearance at dif- ferent seasons (annual species). Moreover, a certain concentration of the salt water is, probably again in consequence of a certain quantity of air, in accordance with the physiological processes in Artemia. I here omit the respiration and the changing of the gill-saes of Artemia with the changing of the concentration of the salt water, simply men- tioning the circumstance, that we most rarely find males with those lowest degraded forms of our Artemia, bearing the characters of Arte- mia Milhausenii, living at the highest density for Artemia, and that, as we will see, the males of that race of Artemia salina (varietas b.) in salt ditches occur, which are most progressively developed and which live, in comparison with our other forms, at the lowest density of the salt water, as will be explained later on. Il.—ON THE GILL-SACS AND THE POSTERIOR BRANCHIAL LOBES IN ARTEMIA AND BRANCHIPUS. I shall speak in this section of the relation of these appendages in Artemia and Branchipus to their external life conditions. First we have to agree as to the determination of these parts. The gill-sac in these forms is called by C. Claus (in his paper on Branchipus stagnalis and Apus cancriformis) ‘“‘ Kiemensaickchen”! (gill-sacklet). Grube calls it “unterer Branchialanhang” (lower branchial append- age). 8 Fischer called it “‘unterer Branchialsack”? (lower branchial sac). The posterior branchial lobes are called by Claus (ibidem) ‘ hinteres Branchialblatt” (posterior branchial leaf); by Grube, ‘‘oberer Branch- ialanhang” (upper branchial appendage); by S. Fischer, ‘‘ oberer Branch- ialsack” (upper branchial sac). The first which demands our attention is that the gill-sacs and poste- rior branchial lobes in Artemia and the salt-lake Branchipus enlarge in length and more so in width during the domestication of specimens, or still more of generations of these forms in salt water of increased density. Specimens ot Artemia salina taken from the Chadschibai Lake, show- ing a density of 9° Eeaumé, I divided into two equal vessels, gradually diluting the salt water in one of them, but increasing the density of the salt water in the other. I kept the water in both vessels at equal height. In both vessels were old and young growing specimens. Both jars stood near to each other and were, with the exception of differently- concentrated water, as regards temperature and all other influences, under the same circumstances. The experiment lasted for four weeks, during which time I daily measured the length and width of the gill- 1“Abhandlungen der kéniglichen Gesellschaft der Wissenschatten zu Géttingen,” vol. xviii, 1873. 2“ Bemerkungen tiber die Phyllopoden” in ‘‘Archiv fiir Naturgeschichte,” 1853, p. 141. 3 Middendorf’s Sibirische Reise, St. Petersburg, 1851, vol. ii, part 1, p. 151. ol H 482 GEOLOGICAL SURVEY OF THE TERRITORIES. saes and the posterior branchial lobes of the domesticated mature speci- mens of both vessels, measuring also the length of the body, finding also the ratio between the length and width of these appendages to the length of the body, inclusive of the furca. The resulting figures gradually in- creased with the strength of concentration of the salt water in one or the other vessel in two different directions, the animals showing in the fourth week of domestication a very considerable difference, which plainly illustrated the increase of the length, and more so of the width, of said appendages at a heightened density of the salt water, and also the de- crease of those parts at a reduction of density of the water. Toward the end of the fourth week the salt water in both jars attained a difference of 10° Beaumé, the gradually-diluted salt water showing then 3° Beaumé ; the salt water of gradually-increased density indicated 13° Beaumé. To compare the size of the gill-sacs and posterior branchial lobes of Ar- temia salina at decreasing and increasing density of the salt water, in measuring I searched for figures which indicated which part of the body- length the length and width of these or those appendages in these or those specimens formed. During the fourth weck of the above-men- tioned period of domestication I obtained the following figures as aver- age results in two diverging directions: At a decreased density At an increased density of the salt water the gill-sacs yielded in length the 24, 3, in length the 22, 4, in width the 46, 5 in width the 40, part of the entire body-length; the posterior branchial lobes yielded in length the 17, 6, in length the 16, 8, in width the 38, 9 in width the 34, 9 part of the entire body-length. I have to remark that toward the end of the period of domestication the resulting figures in the measurements showed considerable oscilla- tions. The cause of it is that in salt water of extremely decreased or extremely increased density the animals soon became so short-lived that the older individuals, as well as the younger just before or soon atter becoming sexually mature, died. ‘The relation of the body-parts in such young, though sexually mature individuals, resembles in some degree the relation of the body-parts in young immature individuals in another surrounding element, then normal for the species; for we observeralso a slight retardation of growth in a suddenly produced ex- treme decrease of the density of the salt water the same as in the in- crease of the density of the salt water. In insufficiently gradually diluting the salt water the individuals of Artemia salina die, as it were, of debility, which cause lies probably in the heightened oxidation in the organism dependent on the increased quantity of air in diluted salt water. The highest development of the furca and the greatest number of its bristles are not incongruous with the lowest density of the salt water which this species can endure for a longer or shorter time, but it is congruous with a concentration not much lower than that peculiar to the species. The more gradual the concentration of the salt water in the domestication of successive generations of Artemia salina is changed the more deviates the mean (for this species) favorable concentration from that concentration which is the mean for it in free nature. In comparing Artemia salina with those degraded forms and genera of this species exhibiting the characters of Artemia milhauseni, living PACKARD. ] TRANSFORMATION OF ARTEMIA. 483 at a very great density of the salt water, approaching the natural deposition of salt, or having attained the latter already, we find a great difference in the size of the gill-saes and the posterior branchial lobes, since the appendages mentioned are considerably larger in the latter than in Artemia salina. To see this, we compare specimens of Artemia salina from the Chadschibai Lake at 9° Beaumé in the first half of Sep- tember with the degraded genera of this species! taken from the Kujal- netzki salt lake at 24° Beaumé, also in the first half of September of the same year, that is, at very different density of the salt water and at nearly the same temperature. Hereby we receive in middle average, and omitting fractions, the following figures: In Artemia salina in Septem- In degraded specimens of Ar- ber at 9° Beaumé— temia salina with the char- acter of Art. milhausenti at 24° Beaumé— the gill-sacs yielded in length the 23, in length the 18, in width the 44 in width the 28 part of their body-length; the posterior branchial lobes yielded in length the 17, in length the 15, in width the 36, in width the 24 part of their body-length. The length of the body of Artemia salina was here taken together with the furcal lobes, exclusive of their terminal bristles, in the same manner as in the above stated experiment; the body-length of the specimens with the characters of A. milhausentt to the end of the abdo- men, as they have no abdominal furea. Since the fureal lobes form a part of the body of Artemia salina and partake of the nutrition like the other body-parts, I have not excluded them in my calculations, although, too, the relations without this furca, which is of inconsiderable length, in comparing the specimens of this or that species, scarcely vary. I also add that I took here, as well as in the above stated experiment, the gill- saes and posterior branchial lobes of the eighth pair of legs, though they are not the largest in this leg. These appendages in mature specimens inerease in size from the first to the sixth pair of legs, on the following legs becoming somewhat smaller, without, however, there being much difference between the sixth and eighth pair of legs. The comparison in any case loses nothing, as the specimens have been compared after one and the same pair of legs. I took these appendages from the eighth pair of legs, coming nearer the mean figure, which would express their size in all pairs of legs. Not less different is also the form of the gill-sacs in the degraded generations with the character of Artemia milhausenii and in Artemia salina. For comparison it is better to take the gill-sacs from the mid- ‘dle pair of legs, as they are of smaller size on the first two or three pairs of legs, and as if not fully developed, having a somewhat deviat- ing form in the last pair of legs, gradually broadening towards the end, becoming in Artemia salina, as well as in specimens with the characters of A. milhausenii, nearly uniformly rounded. In comparing the gill-sacs of the middle pairs of legs of Artemia salina and Art. milhausentt we see that these sacs in Artemia salina are of an elongated form and that Qenr 1Compare my report in the Zeitschrift f. wiss. Zoologie, 1875, vol. xxv, Ist supple- mental part. 484 GEOLOGICAL SURVEY OF THE TERRITORIES. the width of the sac nearly amounts to the halfof its length, while they have an oval form in Art. milhausenii, the width of the bag nearly amount- ing to two-thirds of its length.' In long continued domestication in salt water of gradually increased density L obtained, after several successive generations of Artemia salina, specimens in which the gill-sacs and posterior branchial lobes had the same form and size as those of the specimens with the characters of A. milhausenii, out of the Kujalniker Lake at 24° Beaumé, and in which still other characters appeared peculiar to them in free nature. It is important that in young individuals of A. salinain a certain age the gill-sacs and posterior branchial lobes have nearly the same size and form as in the mature individuals, with the characters of Artemia milhausenit, with the difference that in young individuals directly after quitting their larval state, and even, also, until they liberate themselves trom the provisional parts of the second antenne, the largest of these appendages are not on the sixth pair of legs as in the mature forms, but on the fourth pair. Under the same circumstances under which in mature specimens of Artemia salina the gill-sacs on the fourth pair of legs amount in their length to the twenty-eighth and in their width the fifty-sixth part of the whole body-length, the gill-sacs in the young specimens (in the above-mentioned age) of the same pair of legs measure the seventeenth part of the body-length in length and the twenty- seventh part in their width; but at the time at which in mature speci- mens (at low temperature) of A. salina each gill-sac measured, on the sixth pair of legs, in its length the twenty-fourth, in its width the forty- eighth part of the body-length, in young specimens of the above-men- tioned age each gill-sac of the same pair of legs measured in its length the nineteenth and in its width the thirtieth part of the entire body- length. In young individuals of Artemia salina of this age the gill-saes of the eighth pair of legs corresponded, together with the posterior branchial lobes, in form and size with the same appendages of the same pair of legs in the mature individuals, which have the characters of A. milhausenti, inhabiting most saline water (about 24° Beaumé). In any case, on the whole, these appendages are, in the young specimens of A. salina of the stated age, considerably larger than in mature speci- mens of the same species, being, also, as it must be in the course of de- velopment, larger on the anterior pair of legs to the sixth than on the following pairs. In the young individuals of the age stated the gill-saes measure on the third, fourth, and sixth pairs of legs in their mean length together the eighteenth and in their middle width the twenty-ninth part of the whole body-length, but in mature specimens of this species and under the same conditions the gill-sacs of the third, fourth, and sixth pairs of legs measure in their middle length together only the twenty. eighth and in their middle width the fifty-sixth part of the body-length- From the fact that the gill-sacs and posterior branchial lobes of the young individuals of Artemia salina of the stated age correspond in form and size with the same appendages in the mature individuals bearing the characters of A. milhausenii, we can infer that the latter is a gener- ation of A. salina retarded in its development in consequence of the ap- pearance of sexual maturity before the full development of the parts of the body. However, such an inference would be but partially true. The individuals with the characters of A. milhausentt not only exhibit retarded development under the influence of their surroundings, but they are also the result of the demand of the same element—the result ‘Consult my report in Zeitschrift f. w. Zoologie, 1875, vol. xxv, 1st suppl. part, Tab. VI, figs. 7 and 8. PACKARD.] TRANSFORMATION OF ARTEMIA. A485 of the influence of the organism upon the surrounding element. The hightening of the density of the salt water is naturally accompanied by — a decrease of aeration in such a water, but this decrease again must produce in Artemia an enlargement of the breathing surface, 7. ¢., the surface of the gill-sacs. Concerning the posterior branchial lobes, they (partly also the gill-sacs) have to enlarge themselves in water of high density as auxilliary organs of locomotion, perhaps they also serve as auxilliary organs in respiration, especially in Artemia, wherein the pos- terior branchial lobes are marked out for their greater tenderness, than generally in Branchipus, in which they often are margined with tooth- like spines or little-developed bristles, being, as it were, the beginning of bristles and spines developed on the other branchipeds. According to Leydig’s view the gill-sacs of Artemia and Branchipus do not serve as special respiration organs; but the investigation of Maus! and Spangenberg? make it in the highest degree probable that the inference that the gill-sacs, but not the posterior branchial lobes, are not special respiration organs, is a proper one. Such a conclusion will also be made by the corsideration of these appendages in their re- lation to the surrounding element, under which latter I not only mean the density of the salt water, but also the temperature; toward the latter the gill-sacs are especially sensitive in a high degree, as we shall see further on. From such a great sensibility of these appendages toward the sur- rounding element, we must assume that they have a considerable size in specimens with the characters of Artemia milhausenii, not only owing to retained growth of A. salina, whose younger specimens have larger appendages, but also in consequence of their accession, owing to auy- mentation of their mass, due to the surrounding element, owing to the high density of the salt water. The fact serves as a proof that, in com- paring young individuals of Art. milhausenti with individuals of Art. salina ot the same age, we find the appendages in the former of con- siderably larger size. Only a much earlier state of growth of Art. salina relatively agrees with the later state of age of those individuals, bearing the characters of Art. milhausenii, inhabiting salt water of much higher density than Artemia salina. Beside the interesting changes occurring during the course of development of generations influenced in a known manner by the surrounding element, we here observe an accession and, as it were, an accumulation of mass in the known parts reacting upon the element and developing according to the demands of this element. f call this a direct influence of the surrounding element, and moreover such an influence, toward which the organism keeps active, and I dis- tinguish it from another likewise direct influence of the same element, toward which the organism, so to speak, passively submits. As an ex- ample of this latter influence, I mention the retrograde development of the abdominal furca of Art. salina in salt water of high density, whereby the furca becomes as if atrophied, and, indeed, independently of the sexual maturity in specimens, appearing earlier than the full develop- ment of the body-parts. That influence of the element upon which de- pends the change of form, owing to the changed point of appearance of sexual maturity, I call the immediate influence ot the surrounding element upon the organism. In Artemia, and also to some degree in 1 “Zur Kenntniss des Baues und der Entwicklung von Branchipus stagnalis und Apus cancriformis.” In the ‘‘Abhandlungen K. Ges. der Wissensch. zu Gottingen.” Vol. XVIII, 1873, p. 19. 2 “Zur Kenntniss von Branchipus stagnalis.” Zeitschrift f. w. Z., vol. xxv, 1st supplemental part, pp. 23 and 37. A86 GEOLOGICAL SURVEY OF THE TERRITORIES. other species of crustaceans examined by me, we can observe all these modifications of the influence of the surroundings upon the organism. The formation and full development of the gill-sacs and posterior branchial lobes depend in Artemia and Branchipus not only on the salt-quantity of the water, but also on its temperature; since by a low- ering of temperature the size of the gill-sacs decreases, by a heightening of the temperature they enlarge. 1 do not possess sufficient measure- ments concerning the posterior branchial lobes by which I could attest with correct figures the change of these appendages by temperature, although I obtained unmistakeable results, according to which they, contrary to the gill-sacs, but in a less degree, enlarge by lowering the temperature. Putting tempor anily the posterior branchial lobes aside, I shall treat of the gill. sacs only. In measuring the. gill-sacs in specimens of Artemia salina, gathered in the first halt ot September out of the Chadschibai Lake, I was sur- prised at the figures obtained by the relation of their size to the length of the body, deviating far from the figures received in measuring the suminer-forms, although the density of “the salt water in the lake was but little lessened. Later in the fall, the specimens of Art. salina collected out of the Kujalniker Lake, at a density of the salt water of 15° Beaumé, had even a little smaller gill-sacs than the specimens collected in sum- mer at 9° Beaumé, from the Chadschibai Lake. Subsequently, I di- vided the young and old specimens taken from the Kujalniker Lake at a density of 13° Beaumué inte two sections and domesticated one section at an average temperature of 14° [Réaumur?] the other section at an average of temperature of 7°-+- Réaumur. A considerable ditfer- ence showed itself after two weeks, those individuals living at a lower temperature, but kept by me at a uniform concentration in both jars, had their gill-saes, especially in width, considerably smaller. In indi- viduals living i in higher temperature, each gill-sae on the eighth pair of legs on the average amounted to the twenty-second part in “length and the forty-second part in width of the whole body-length; in individuals living at a lower temperature the gill-sac of the same pair of legs gave the twenty-fifth in length and the fiftieth part in width of the body ‘length. It seems that temperature has upon the gill-saes a more vigorous effect than the concentration of the salt water; on the other hand, the density of the salt water has a stronger inflaence on the posterior branchial lobes. The circumstance is hereby illustrated, that in the first, red variety of A. salina (varietas a, description farther on), the gill-sacs are smaller, but the posterior branchial lobes are lar ger than in A. salina. Not to mention so many figures, I point to the width of these append- ages, since in these forms they differ in length little from each other. In measuring the specimens of A. salina at a density of 15° Beaumé, and the specimens of the first, red variety at a density of 16° Beaumé, at one aud the same (moderately low) temperature, I found that the width of the gill-sacs of the eighth pair of legs in A. salina was the thirteenth, but in the stated variety it was the forty-ninth part of the body-length, and that in A. salina the width of the posterior branchial lobes was the thirty-fifth, but in the red variety it amounted to the thirty-seeond part of the whole body-length. In this manner, besides the fact that the specimens of this variety were collected at 2 higher density of salt water than the specimens of A. salina, their gill-saes are nevertheless smaller than in the latter; but the posterior branchial lobes are larger in the variety than in its species, this corresponding already with the larger quantity of salt contained in the water. Such PACKARD. ] TRANSFORMATION OF ARTEMIA. 487 a phenomenon is only explicable by the fact, that in a state of nature, on the average, a lower temperature is, together with a higher density of the salt water than with A. salina, peculiar to the first variety of A. salina (varietas a). The gill-sacs, as special organs of respiration, must become smaller by a lower temperature, whilst the posterior branchial lobes, as the auxiliary organs of locomotion, must enlarge by the greater density of the water dependant on the lower temperature and the higher con- centration. But since the density of the salt water depends more on its concentration than on temperature, it is obvious why, by domestica- tion of Artemia, we observe more changes in the posterior branchial lobes by the concentration of the salt water than by temperature. The first of these varieties of A. salina (varietas a.) corresponds amongst our forms of Branchipus mostly with the species Branchipus spinosus Milne-Edw., according to the relation of the gill-sac and posterior branchial lobes and some other characters, together with the element which it inhabits. Brunchipus spinosus is characterized among our forms of Branchipus in a similar manner as the first variety of A. salina, and A. salina by small gill-sacs and large posterior branchial lobes, only herein Branchipus spinosus is the difference in size of these append- ages considerably larger. Such a phenomenon also fully corresponds with that element which Branchipus spinosus among our salt-water forms of Branehipus principally inhabits. It lives, in comparison with our other Branchipus forms, in a lower temperature, but at a higher con- centration of the water. Especially in younger age and ata certain time the gill-sacs and posterior branchial lobes much resemble the ap- pendages of the mature specimens of the stated variety of A. salina (varietas a.), and altogether in younger age of the specimens of Branch- ipus there is a certain period when their leg-appendages in measure- ments more approach the appendages of the mature forms of Artemia than the appendages of mature forms of the same species of Branchipus. For comparison we take mature individuals of Branchipus spinosus and young individuals of this species, some time after they quitted their larval state, when the section between the eighth and ninth apodous segments of the abdomen has scarcely just been formed, and the furea is still two or two and a half times shorter than the section consisting of the two last segments of the abdomen, and which is homologous with the last (eighth apodous) segment of the abdomen in Artemia. In the mature Branchipus spinosus the furca equals the section consisting of the last two apodous segments. We obtain the following proportions: In the old specimens of In the young specimens of Branch. spinosus— Branch. spinosus— the gill-sacs amounted in length the 40, in length the 24, in width the 118 in width the 61st part of the whole body-length; the posterior branchial lobes amounted in length the 19, in length the 16, in width the 37 in width the 28th part of the whole body-length. The first variety of A. salina (varietas a.) is in relation to this, especially concerning the gill-sacs, between the species A. salina and the young specimens of Branchipus spinosus. I only kept the figure of the measurement of varietas a. of A. salina at such a salt capacity 488 GEOLOGICAL SURVEY OF THE TERRITORIES. of the water, at which it (the variety a.) forms the transition to the cor- responding variety of A. milhausenit, that is, at 15°, 16°, and 18° con- centration after Beaumé’s instrument. In concluding, it results that at such a concentration of the salt water, at which the above stated meas- urements of A. salina showed themselves, 7. ¢., at 9° Beaumé, and the temperature of the month of September, we must obtain the following figures for this race: The gill-sacs The posterior branchial lobes must amount in their length the 25th, _ the 16, 5th, in their width the 52d the 34th part of the whole body-length. The variety Branchipus ferox, hereabouts living in salt water ditches, and to which is peculiar a lesser concentration of the salt water, how- ever at a higher temperature than that peculiar to the species Branchipus spinosus, yields the following figures, in relation to the gill-sacs and posterior branchial lobes: The gill-sacs The posterior branchial lobes amount in length to the 24th, the 20th, in width the 56th the 43d part of the whole body-length. The variety Branchipus ferox (from salt-water ditches) is, in its leg- appendages and according to the element which it inhabits, in propor- tion to Artemia salina as Branchipus spinosus is to varietas a. of A. salina. Especially those generations of A. salina which live in salt-water ditches of about 4° Beaumé, or the generations of the second variety of A. sa- lina (varietas b.) are in relation to gill-sacs and posterior branchial lobes and some other characters, alsoin the element in which they live nearer the salt-lake generations (from salt-water ditches) of Branchipus ferox (varietas). I must add here that the legs themselves are longer in Branchipus fero.e var. and in A. salina than in Branchipus spinosus and in A. salina varietas a., and that only on this account the posterior branchial lobes of the forms of the one or the other category relative to length have no great differences. But the length of the legs corre- sponds with that temperature and with that concentration of the salt water which is peculiar to each of these forms.! Concerning Branchipus medius mihi, we can nevertheless recognize abstractedly from the point that it forms a too isolated species in its characters and in the relation-figures of its gill-sacs and posterior bran- chial lobes, the result of the effect of the element in which itis dis- tributed, as I have mentioned in the description of this species.’ The knowledge of the effect of the surrounding element upon the gill- sacs and the posterior branchial lobes in these animals is important because the differences of size between these appendages, according to authors (Milne-Edwards, S. Fischer, Grube), represent no important species-characters. It is here the place to add a few remarks which show how far the life of A. salina depends on the air-capacity (actually the oxygen of the 1Consult any paper in the ‘‘Schriften der Neurussischen Gesellschaft der Natur- forscher,” 1875, vol. iii, 2d part, pp. 297 to c00. 2Tbidem, pp. 305 to 313 PACKARD.] TRANSFORMATION OF ARTEMIA. 489 air) of the salt water. By changing the air-capacity of the salt water by a changed concentration of the water, we can at least explain a num- ber of interesting phenomena in the life of Artemia. 1. If we in certain limits dilute the salt water too much in domesti- eating Artemia, then the animals become, by the too much reduced con- centration of the salt water, transparent, attenuated, their intestinal canal empties and becomes translucent, the gill-sacs often blacken, and the animals will die at the bottom of the jar, as it were, of debility. Butif we in time notice at the excessive dilution of the salt water the sckness of the animals, and if we, instead of augmenting the concentration of the salt water, heighten its temperature a few degrees, the diseased animals will become animated, the intestinal canal fills itself, the mo- tions become more rapid, the animals leave the bottom of the jar, doing well in such diluted salt water at a corresponding higher temperature. It seems tomethat such a temperature supplants the superfluous air of the diluted salt water, which in the organism of the animals produced a too great oxidation, leading to weakness, during which the nutritive sub- stances could not replace the consumption. If by too strongly diluting the salt water the Artemia is consumptive, on account of want of nour- ishment, owing to the dying off of those microscopic organisms on which Artemia lives, these animals would not have revived so soon after a cor- responding increase of temperature. Moreover, microscopic organisms appear in the diluted salt water in great number, even Infusoria, while Joly! observed that Artemiz are omnivorous, and that they principally live on the lowest organisms of the vegetable kingdom peculiar to the salt lakes, such as various forms of Chlamidomonas, zoospores of Clado- phora, &c. 2. If we, in domesticating Artemia, excessively increase the concentra- tion of the salt water and not sufficiently gradually, its alimentary canal becomes solidly constipated, the animals keep nearer the surface of the water and die there, especially during exuviation, which is hereby just as difficult to overcome as in too much diluted salt water. However, if we in time in this case lower the temperature, instead of diluting the salt water, the animals, even at a too high concentration of the salt water, revive, doing well in such a water with, to a certain degree, low- ered temperature. It seems to me that in this case such a combination of high concentration and temperature is formed, bearing to the equi- librium of aération in the water, 7. e., the quantity of air in the salt water is lessened by the increase of its concentration for just so much, as it is, according to physical laws, heightened by lowering the temperature. A want of nourishment in very saline water is here out of question, since such a water is inhabited by immense numbers of simple organisms, and even at a concentration, allowing self-deposit of salt, great quanti- ties of a red Monad occur, which is known under the name of Monas dunalit Joly (Diselmis dunalit Dujardin=Chlamidomonas dunalit Raben- horst). 3. If we gather out of a salt lake the adult Artemia, together with their larve, and dilute the salt water to excess, then the larve will soon expire, while the adult individuals long after resist the dilution of the salt water. It appears that the larve of Artemia die faster in too strongly diluted salt water, because the small stock of material in the organism is not sufficient toward the intense oxydation in consequence of an excess of oxygen in such a water. 4, Ina broad jar and at alow surface of water these animals also 1 Joly, Sur ’Artemia salina. Annales des sciences naturelles, vol. xiii, Zoologie, pp. 246 and 255. 490 GEOLOGICAL SURVEY OF THE TERRITORIES. prosper in such non-diluted salt water, which was taken from the salt lake at a middle concentration peculiar for this species (Artemia salina), but they do not prosper so well in a narrower jar with higher water-sur- face, as they soon die in such a water. In the same narrow vessel and at the same high water-level these animals will still prosper if the salt water is proportionally diluted. In this latter case the animals are so circumstanced, as in more Saline water in the broader jar with lower water-level. The diluted water contains more air, it being more pene- trable and better adapted for gas exchanges. 5. Accepting the fact that the water in a salt lake at a given time shows 10° Beaumé, and that it is populated with crustaceans of the genus Artemia, if we now take two equal vessels, placing in one of them water of this salt lake and a certain number of specimens of one genus of these crustaceans, and placing in the other jar specimens of the same animals out of the same salt lake, diluting the salt water to 7° or 6° Beaumé, a large number of animals will die in the first vessel under the same conditions, while keeping up the initial concentration of the water, but in the second vessel the majority of the animals will remain alive. In the second case, that quantity of air is as if restored, which is wanting in the first, apparently by the influence of the vessel itself, as the water in the vessel is under different conditions from that in the salt lake. This is all the more so the case with a summer-like tempera- ture. 6. The animals prosper also in a non-diluted salt water better at a temperature lowered to a certain degree than at a higher temperature, yet they do much better in diluted salt water, when the concentration of the salt water has not been reduced above a certain degree. 7. Finally, the enlargement of the surface of the gill-sacs in Artemia with the increase of concentration of the salt water proves, as mentioned already above, apparently the dependence of Artemia in this relation principally on the reduction of air-capacity of such a water, even if the gill-sacs, according to their location and formation, as it were, in these animals represent moditied organs of locomotion. It remains for the physicists to determine how considerable is the solubility (the coefficient of assumption or of capacity) of the oxygen of the air in salt water when the variation of its concentration varies. In relation to this I can find no accurate data. IIIl.—THE GENERA ARTEMIA AND BRANCHIPUS, AND THE RELATION OF SOME OF THEIR SPECIES TO THE SURROUNDING ELEMENTS. In the whole order of Phyllopoda the species of the genera Artemia and Branchipus are apparently those which are most sensitive to the influence of the surrounding element, in such a sense that a modifica- tion of the surrounding element is capable of producing in their genera- tions in a pretty short time visible mutations in theirforms. A change of the surrounding element can even in one and the same generation produce such a variation of some parts of the body that it is difficult, in a state of nature, to immediately distinguish those forms which are most closely allied to each other. The species of these genera have been found by me mostly in salt lakes and salt ditches (Artemia exclu- sively), whereby they distribute themselves in such a manner that each species is peculiar to a certain concentration, and the change of this con- centration in artificially domesticating their generations produces a change of form in the direction towards the next species or race which lives in another concentration of salt water, toward which side the PACKARD. ] TRANSFORMATION OF ARTEMIA. A91 change of concentration in the artificial domestication yielded. The temperature hereby co-operates with the concentration of the water. Relating to this, the forms of the genus Artemia deserve special atten- tion. 1.—Artemia salina Milne-Edwards. This species occurs here in the closed Chadschibai and Kujalnitzki Lake and in the salt-water ditches. It sustains a fluctuation easily noted in the variation of body-parts, and in its growth at a fluctuation of the concentration of the salt water from 5° to 12° Beaumé, in which limits it was found by mein the water basins. Ataconcentration of the salt water which is higher than 12° (and still more than 15°) Beaumé, our Artemia salina commences in its generations to exhibit transitory forms towards Artemia milhausenit Milne-Edw., the latter living by a far greater concentration of the salt water than Artemia salina, that is, at self-deposition of salt or not far from it, 7. ¢., at 24° and 25° Beaumé, To the description of Artemia salina given by the authors we have to say, that the representation of characters of this species, as altogether of the whole genus Artemia in the present time, is very inexact and vague. Firstly, we find mentioned that Artemia possesses but six terminal segments, while there are eight, since we have to count also these two first apodous segments of the posterior part of the body, on which, in the species of Artemia-genera, the external genitals occur. Grube,! in making of Artemia a section or a sub-genus of the genus Branchipus, repeats the mistake of his predecessors, saying, in the dia- gnosis ot the group Artemia ‘‘ segmentis apodibus sex.” Only in Artemia milhausenti, which lives at a very high concentration of the salt water, are the articulations between the segments, especially between the more pos- terior ones, some what less distinct; but we can nevertheless, at least in specimens bearing the characters of this species from our districts (also from the Krimea), always distinguish them, especially in fresh material which has not been preserved in weak alcohol for along time. In the lat- ter case, even in Artemia salina, only with difficulty can we see the articu- lations of the abdomen. If in any region Artemia milhausenti cecurs with connate, apodous segments, be it in some or all specimens, then it is very likely that we, even in such an Artemia, cannot count six apo- dous segments. Secondly, it has been considered hitherto as the prin- cipal characters of the genus Artemia, that in the species of this genus the abdomen ends with a short furca, whose branches are bristles only on the end, and such a diagnosis of the genus Artemia we discover even in the very latest zoological hand-book. Grube? repeats in the diagnosis of his group Artemia in the genus Branchipus the characteristics of the genus Artemia of his predecessors, in saying: Appendicibus caudalibus brevibus, apice tantum setosis aut nullis. Our Artemia and two of its varieties, which I shal! mention later on, have the bristles not only on the end but also on the sides of the fureal lobes, just as in the species of Branchipus, which usually only have more bristles. Besides the Arte- mia salina from the district of Odessa I have the same distribution of bristles on the furca in specimens of this species brought from the neigh- borhood of Astrachan and the Krimea. We have here dry years with a hot summer where the concentration of the salt water in the Chad- schibai Lake is too high for Artemia salina. Then many specimens of this species have, especially in summer, bristles only on the end of the 1“ Bemerkungen iiber die Phyllopoden” in ‘‘Archiv fiir Naturgeschichte,” 1853, p. 139. 2 Opus citatum, ibidem. 492 GEOLOGICAL SURVEY OF THE TERRITORIES. furca, the furca being at the same time shorter and less bristled, as un- der opposite physical conditions. If we compare the descriptions and illustrations of Artemia salina of the various authors, we find that they agree less among themselves than they do compiled from specimens of Artemia salina, or taken from the deseriptions of specimens gathered under various physical conditions, that is, at various concentrations in combination with temperature. Milne-Edwards! says: That on each furcal lobe in Artemia salina occur three or four bristles, while Grube? states, in his diagnosis, that 5 to 8 bristles occur on each furcal lobe. We find in Artemia salina from our district, under various behavior of the surroundings, on each lobe of the furca 4 to 12 bristles, seldom more. In the third form, living in salt ditches in the neighborhood of Odessa and the Krimea, we find 12 to 22 bristles on each lobe of the pretty- well developed furca. I take the latter form to be another variety or race of Artemia salina, though it obviously originated from generations of this species with progressive development under the influence of salt- water ditches, having a lower saline capacity than the salt lakes, popu- lated with Artemia salina. In those cases, where in our Artemia are more than five or six bristles on each lobe of the furca, the bristles are distributed not only near the end but also on the sides of the furcal lobes. The specimens of Artemia from the very saline Kujalnitzki Lake, having but three, two, one bristles on the end of the fureal lobes, or lacking them altogether, in the latter case having a very slightly de- veloped furca, with the other parts moditied ; those I take to be tran- sitory forms between Art. milhausenti and Art. salina; altogether the distribution of bristles on the furea, the number of bristles, and the shortness of the furea itself can not. serve aS an important distinctive character between the genera Artemia and Branchipus, and much less SO as a point of distinction between the species of Artemiz. In Artemia salina, as one of the most constant points of distinction, we observe the termination of the superior antenne or antenne of the first pair. The upper antenna here terminates with two protuberances or papille of the form of a truncated cone, one of which is somewhat stouter than the other. At the terminus of the stouter, broader cone, we notice three moderately short spines, only one of which can be seen on the terminus of the thinner cone. Each spine is a litle curved, having at its base a quadrate, yellowish, light-refracting body. These four spines are the olfactory bristles of these animals. Immediately under the terminus of the upper antenna, near the end of its upper surface, arise three moderately long and usually curved bristles. Beside the mentioned terminations of the upper antenne we have to complete the description of Artemia salina by the following characters. In Artemia the posterior part of the body consists of eight apodous seg- ments, the first two of which bear the external genital organs, but the last eighth segment is twice as long as the preceding, being homo- logous to the two last apodous segments of the Branchipodes. The furca in Artemia salina is of very variable length. In our Odessa A. salina the furea is on the average six times shorter than the prolonged last abdominal segment.- The bristles of the furca are also of very variable number. We notice in our Artemia salina on each lobe of the furca from four to twelve bristles, which are not only near the end of the lobes, but for the greater part distributed along their sides, at least if there are more than four or six bristles on each lobe. Toward autumn at a lowering of temperature and dilution of the salt water of the Chad- 1 Histoire naturelle des crustacées, Vol. III, p. 370. 2“ Bemerkunken itiber die Phyllopoden,” Arch. f. Nat. 1853, p. 144. /PACKARD.] TRANSFORMATION OF ARTEMIA. 493 schibai Lake by rain, the furea becomes in the late generations longer and the number of bristles greater, since under these conditions the growth of Artemia salina is less retained and the sexual maturity ap- pears not so early, that is, not earlier than the complete development of the body-parts, which, however, is not so well defined in this species, being, as it were, but a relative matter. Also the termination of the upper antenne, being the most constant character of this species, modi- fies to a certain degree. For instance, I found in the autumn of one year, at low temperature and diluted salt water of the Chadschibai Lake, in many individuals of A. salina near the end of the upper an- tennee five olfactory bristles, instead of the normal number of four. In domesticated generations of this species in-gradually diluted salt water we perceive also five olfactory bristles on the upper antenne. With the distinctive characters of A. salina we have also to include the form of the gill-sacs. They are in A. salina of an elongate form, their width being on the average twice less than their length. This character dis- tinguishes A. salina from A. milhausenit, in which the gill-saes are of oval or more rounded form, being on the average two-thirds as wide as long. As another important point of distinction of A. salina from the nearest allied races, [ mention the proportional size of the posterior part of the body constituting the apodous segments; the anterior part from the beginning of the head to the end of the last leg-bearing segment, i. e., to the beginning of the first apodous segment and the posterior part of the body, from the beginning of the first apodous segment to the end of the last segment before the beginning of the furca. The furca does not come into account, as its length is variable, being for instance in A. milhausenit, with which the other forms must relatively also be com- pared, entirely missing. We find that in A. salina the anterior part of the body is somewhat shorter than the posterior; proportionate to it as five to six or as fivetoseven. This relation of the parts also depends upon the concentration of the salt water in which these generations live. In reduced concentration the posterior part has an inferior size than in the higher concentration. Altogether the postabdomen of A. salina becomes longer and more slender with increased concentration. In many of our specimens with the character of A. milhausenti, which live at self-deposition of salt or nearly so, the anterior part of the body is twice shorter then the posterior part. To the most variable characters of A. salina we must reckon that reddish layer which lines the anterior part of the alimentary canal in the shape of a tube, which layer Joly! calls the liver, and Leydig? the stomach, as he separates it from the following part, the alimentary canal to the anal orifice. For better distinction I shall call the anterior part the stomach part of the tract, the second, the posterior part. The stomach part of the tract terminates in Artemia about in the middle of the seventh apodous segment, but the length of this part depends upon the concentration of the salt water inhabited by the generations of this species, and partly also from the growth (age) of the specimens. At high salt capacity of the water this part of the tract does not reach to the end of the sixth apodous segment of the abdomen; at lower salt ' “Sur Artemia salina” in Annales des Sciences nat. 1840, pp. 238 to 239. 2. Leydig, ‘‘Ueber Artemia salina und Branchipus stagnalis,” Zeitschrift f. w. Z. 1851, pp. 283 to 264. 3 The first part of the tract Claus calls ‘‘Magendarm,” the second part, the ‘ End- Darm” in his ‘‘ Zur Kenntniss des Baues und der Entwicklung von Branchipus stag- nalis und Apus cancriformis,” l. ¢., as above. 494 GEOLOGICAL SURVEY OF THE TERRITORIES. capacity of the water, but especially in autumn, it exceeds by far the beginning of the eighth abdominal segment. Likewise this part is longer in old individuals than in young, otherwise sexually mature speci- mens. If we examine, relative to this, specimens on the extreme concen- tration-limits of the salt water, we find a great difference amongst them. In A. milhausenit the stomach ‘part of the tract scarcely reaches to the beginning of the sixth apodous segment, but in our species of Branchi- pus this part terminates not far from the anal orifice. Finally, we must mention as a character of our A. salina the following: The claspers, or the lower antennz in the males, are much broadened on their second joint, having such a form as the male claspers of A. art- etina, according to a drawing of S. Fischer.! On the anterior part of the male claspers, between the head and the protuberances, serving to clasp the female with, near the bent-down margin, there are two groups of ten-pin-shaped teeth or spines, in one group on each side. It appears that these denticulate groups corre- spond as rudiments of the well-known appendages, occurring on the claspers of many species of Branchipus, as for instance in Branchipus spinosus. Such bundles of teeth or spines occur also in that form of Artemia examined by Ulianin from Sebastopoiis, and which was re- garded by him asa race of Branchipus arietinus Grube (= variety of Avt. arietina Fischer). Artemia salina Milne-Edw. varietas a.—This form, called by me Arée- mia salina var. a., approaches the species Artemia salina so much that, beside its larger size, no other distinct characters exist by which we, with the general variability of so many characteristic points of the Artemiz of this species, could distinguish the same. However, if we have speci- mens before our eyes of this or that form, we must confess that we have to do with forms differing so much that we even could regard them as different species of the genus Artemia. A view of profound truth has been expressed already in 1871, by Professor C. Th. von Sieboid, on the comparison of descriptions of Ar- temia salina ot various authors. Siebold says:? ‘In comparing the vari- ous descriptions and illustrations given of Artemia salina, we become convinced that probably with this species-name entirely different species or races were marked out, and therefore a revision of the species of the genus Artemia by carcinologists would be recommendable, though this, however, would necessitate a comparison of vast material, especially as the hitherto insufficient diagnoses of the species of Artemiz, without reference to the characteristic formation of the male heads, have been compiled.” Further on Professor Siebold, in perusing the descriptions of the second antenne of the males in Artemia salina and that of the postabdomen of this species, foresaw what is now actually corrobo- rated. I find two principal races of Artemia salina, one of which is of smaller size, the Artemia salina, but the other is Artemia salina varietas a., and there are, besides, still other changes of its generations depend- ing on various concentrations of the salt water, including also those degraded and modified generations of the two races of Artemia salina, which are, as I suppose, recorded in zoological literature under the name of the species of Artemia milhausenii. The main distinctions of the variety a. of the species Art. salina forms another mean length of it. Accepting as the mean length of Artemia salina six lines, we must accept eight lines of French foot for 1Middendorft’s sibirische Reise. St. Petersburg, 1851, Vol. II, 1st part. Table VII, fig. 32. 2“ Beitriige zur Parthenogenesis der Arthropoden.” Leipzig, 1871, p. 203. PACKAnD,] TRANSFORMATION OF ARTEMIA. 495. the mean length of Artemia salina var. a. As a rule the specimens of this variety are two lines or nearly so larger than the specimens of the species. With the mean size as a point of distinction, the fact may serve to show that the posterior part of the body in this variety from the begin- ning of the first apodous segment to the end is somewhat longer than in the normal species. The anterior part of the body in Artemia salina is in proportion to the posterior part in most cases as 5 to 6 (or 5 to 7 in higher concentration of the water), but in this variety usually as 5 to 8, slightly fluctuating to this or that side in different salt capacity of the water. The postabdomen in this variety is not only longer, but also slenderer than in the normal species. The furea is longer in the variety than in the species, and the number of bristles on the furca is also greater in the variety. If the furca in the species is six times shorter than the last prolonged segment of the ab- domen, then it is but four times shorter than that segment in the race. Lut we also meet with specimens of the species with such a proportion of the furea to the last segment, as in this variety, and again we see fureal lobes in specimens of the variety with the same proportion to the last segment as in the normal species. In Artemia salina occur from 4 to 12 bristles on each lobe of the furca, rarely more; in the variety a. of Artemia salina there are from 8 to 15, but seldom more. In this race, aS well as in the species, we find however also less than four bristles on each furcal lobe; there occur three, two, and one bristle on each lobe, especially in more concentrated water; but such specimens and generations must, by modifications of other structures, be regarded as transitory forms between Art. salina and A. milhausenit. The claspers or second antenne of the males of the variety are less broad than in the males of the normal species. The groups of spines or teeth on the anterior part of the claspers, near their base, are some- what better developed in the males of the variety than in the males of the species A. salina. The second antenne of the females of this race are a little smaller and narrower than in the normal species, just as the inale claspers are narrower than in the species. The specimens cf the variety a. of Artemia salina are of a far darker red color than the specimens of the species, although there occur also specimens with the same color amongst the latter. The variety a. of A. salina is usually of a red color, and is found here in the Kujalnitzki salt lake, but Art. salina is usually of a grayish or reddish-gray color, occurring principally in the Chadschibai salt lake, in which occur also specimens of red color,’ which represent, as it were, the points of aber- ration of the species toward its race (var. @.). In the variety a. of Artemia salina the gill-sacs are a little smaller; the posterior branchial lobes, on the other hand, a little larger than in the normal species. According to the other structures, it does not differ from the species Artemia salina; and all that was said relative to the influence of the surrounding element about the species refers also to the variety a. of A. salina. All the characters of this variety correspond with the circumstance that specimens of them, in comparison with the specimens of the spe- cies, prosper better at a higher concentration of salt water, but at a lower temperature. ! The specimens of the species are about 14™™ length, the specimens of this variety 17 or 18™™, The summer generations are in one, as well as in the other form, a little smaller than the tall generations. 2The Kujalnitzki Lake has more saline water than the Chadschibai Lake. A496 GEOLOGICAL SURVEY OF THE TERRITORIES. Important for my purposes is the following remark of Dr. Nitsche concerning Branchipus Grubvi (von Dybowski) from the neighborhood of Leipzig: “Further on it exhibited the remarkable circumstance that two races of this species occurred: a larger one about 20 to 22™™ long, and a smaller one about 15"™ long. These lived in various ditches, and those inhabited by the larger race contained far less specimens than those inhabited by the smaller race.”! The existence of two races of different sizes of Branchipus Grubii and the circumstance that the specimens of these races lived in different ditches is of importance. It would be interesting to learn? whether this ‘‘ratio quantitatis” between two races occurs at any time of the year (which I do not accept). In- formation about this latter point would especially be of value, whether the specimens of these two races occurred together in one and the same. ditch. Artemia salina Milne-Edw. varietas b., like variety a., in reference to the species, represents, so to speak, another branch of the middle radi- cal form, from which it, together with the normal species, originated in the distribution of generations in a modified element; this second variety (var. 0.) represents in its distribution in an element of lesser concen- tration of the salt water the progressively developed generations of the species itself. Variety 6. occurs in salt ditches near Odessa and Sebastopolis. In salt ditches near Odessa I found it at a concentration of 4° Beaumé, while at the same time in the other salt ditches of higher concentration specimens of A. salina occurred. The length of the specimens of variety b. scarcely differs from the length of specimens of the normal species; its postabdomen, however, is shorter and stouter than in the species; the furca is by far longer and more bristled than in the normal species. The postabdomen (exclusive of the furca) is in this race also a little shorter than the anterior part of the body, at least in the young, though sexually mature specimens, while the same somewhat elongates with age. As the posterior part of the body elongates with the growth of the specimens to mature and old age, and likewise in heightening the concentration of the salt water, we can presume that it is in A. salina var. b. either shorter than the ante- rior part, or equals it, or is scarcely longer than the same, while in the species A. salina the posterior part of the body is considerably longer than the anterior.2 Only in the young specimens of the species itself, some time before becoming sexually mature, the posterior part of the body is still shorter than the anterior. In any case, such a character cannot sharply demarcate this variety from the normal species. There are other characters by which we can distinguish them. The furca of the variety b. does not show any simple conical protuberances at the end of the abdomen like two prolongations of the same, but real—even if not segmented from the end of the abdomen, but only by a transverse easily noticed ring, separated at the sides from its base—divided fae lobes. They are rather large and more developed than in other forms of Artemiz. They have ‘the Shape of lancet-like plates, tapering 1H. Nitsche: ‘‘Ueber die Geschlechtsorgane von Branchipus Grubii (von Dyb.).” Zeitschrift, f. w. Z., vol. xxv, p. 231. irom Dr. Nitsche we cannot expect to hear all the singularities referred to the race of Branchipus Grubei. Especially inquiring into the structures of the sexual organs of Branch. Grubii, which formed the topic of his dissertation, Nitsche sufficiently pointed out the existence of two races of Br. Grubii, calling it a remarkable circum- stance. ’The postabdomen is on the average longer and slenderer in the species of Artemia than in those of Branchipus. PACKARD. ] TRANSFORMATION OF ARTEMIA. 497 toward the tip, with sides oe ends bristled, whose number fluctuates on each lobe between 12 and 22. The furcal lobes are in length only two and a half times shorter than the last abdominal segment. This last (eighth apodous) prolonged segment of the abdomen differs here in the important peculiarity that it possesses, a little above its middle, often a more or less distinct transverse ring, like an articula- tion, as existing between the eighth and ninth apodous segments of the abdomen in the species of Branchipus, in which the furcal lobes are in the majority strongly developed, as it were, on account of the ninth apo- dous segment, which is rather short with them. This transverse ring is just below the last sensitive bristles, occurring in A. salina a little above the middle of the eighth apodous segment of the abdomen,! as also at the end of each of the anterior apodous segments just before the segmentations. If this transverse ring on the eighth prolonged apo- dous segment was more conspicuous in variety b. of A. salina, and if it was of ‘constant occurrence, then we would have a form with nine apodous abdominal segments, which is one of the principal characters of the genus Branchipus. But since there is no actual segmentation on the eighth apodous abdominal segment of variety b. of A. salina, this race forms, remaining with the genus Artemia, a transitory link be- tween this genus and the genus Branchipus. With the latter genus the examined race possesses by far more harmony than the other hith- erto known forms of Artemie. The prolonged, laterally and terminally, bristled furcal lobes, the transverse ring between these lobes and the abdominal end, the shortness of the postabdomen, the lesser length in proportion to these parts in other Artemia forms, the greater thickness of the segments of the postabdomen, the more or less distinct traces of segmentation on the last (eighth) apodous, homologous with the two last (eighth and ninth apodous) segments of Branchipus, likewise also yet other less conspicuous characters of Artemia salina varietas b., demonstrate this. Amongst the characters in which the examined Artemia-form incline to the genus Branchipus I will note two more. One of them consists in the presence of groups of spines on the ventral and lateral surface of the postabdomen, on the end of the third, fourth, fifth, sixth, and seventh apodous segments, anteriorly of each segmentation, and a little before the middle of the eighth apodous segment before the more or less notice- able transverse ring on this segment. On some segments occur two ageregations, one on each side, but on others occur four aggregations arranged circularly around the segment. Irom the middle of each ag- gregation arises a sensory bristle, which, together with the groups of spines situated near their base, can easily be seen under a magnifying power of 350. In A. salina and its variety a. occur, instead of groups of spines, on the same spot groups of cuticular cells, which do not rise above the surface of the integument (from which they are somewhat differentiated), and which give rise to one bristle arising from their midst. These complexes of cuticular cells in A. saling and in its variety a. are homologous with the mentioned complexes of spines in race b. of A. salina and the species of Branchipus. In domesticating several successive generations of the species A. salina in gradually diluted salt water, I obtained, together with the other corresponding characters on the post- 1On this spot of the last segment of the abdomen we obtain the segmentation in the species A. salina by domesticating several of its generations in eradaually diluted salt water. Compare my paper in the ‘‘Schriften” of the third meeting of Russian natu- ralists at Kiew, Zoological section, pp. 71 and 87; also, my paper in Z.f. w. Z., xxv, 1871. 32 H 498 GEOLOGICAL SURVEY OF THE TERRITORIES. abdomen, the development of groups of spines from the above-men- tioned groups of cuticular cells. However, these cuticular cells also commence in free nature in fall generations of the species A. salina to point themselves on their tips and to elevate themselves above the in- tegument. ‘To be sure under such external conditions the enlargment of the furea and the number of their bristles testify in these specimens to a lesser retention of growth than in summer at higher salt capacity of the water and at higher temperature. These cuticular groups of cells, or, in known cases, these denticular groups of spines occur- ring near the base of the sensory bristle on the abdomen of A. salina and its varieties, are homologous with the minute denticular spines occurring near the base of the sensory bristles on the lateral sur- face of the postabdomen in both sexes of Branchipus ferox and B. spinosus. Concerning the large spines on the ventral surface of many apodous segments (from the third to the eighth) of the abdomen of the males of B. spinosus, they apparently represent a phenomenon inde- pendent of the sensory bristles and their basal denticular groups of spines, or both structures are so connected with each other that the substituted sexual characters can be connected with the sensory or- gans, for which we have to take the large ventral spines of certain ab- dominal segments of the male B. spinosus. Beside these large spines, occur, exteriorly of them, at the side of the segments, in the males as well as in the females of this species, groups of minute denticular spines, each with a sensory bristle. The last of such conspicuous characters of the variety D. of A. salina, approximating this form to the genus Branchipus, consists in the fact that the male claspers on the anterior ventrally-directed side near the margin between the rugose protuberances and the middle have not only at the sides a complex of teeth, but also that they have on these spots several protuberances or integumental duplicatures. It seems to me that those teeth occur on that spot where certain appendages on the male claspers of many species of Branchipus oceur. The claspers themselves are considerably smaller in the males of this race than in the species A. salina. Still further on a cireumstance in the biolog gy of A. salina var. b, points to the inclination of this form towards the species Branchipus. It is that the males of this variety evidently occur comparatively more frequently than in the other forms of Artemia. Of sixteen specimens brought to me indiscriminately from the Krimea, six of them proved to be males.1 Such a percentage of males I never met with in other species of Artemia, among which the males are generally rare. Near Odessa L had succeeded hitherto in finding but one female of this variety, together with B. spinosus in a salt-water ditch of 4° Beaumé, none of the other forms of Artemia occurring there. Variety b. of A. salina, however, lives among all forms of Artemia known to me at the lowest concen- tration of salt water in salt ditches, in which live also several species of Branchipus, some at higher, others at lower concentration of the salt water. This circumstance is of importance, inasmuch as in species of Branchipus, which do not indicate such a difference in figures as the species of Artemia, parthenogenesis is unknown, while it without doubt exists in Artemia, and in this number probably also in variety b. of A. salina, being yet solely on the limits of the genus Artemia. Very rarely ‘In the summer of 18761 found in the neighborhood of Sebastopolis, in sev eral salt-water ditches and smaller salt lakes of lesser salt capacity of the water, progress- ively developed generations of 4. salina; nearly half of their number were ‘males. PACKARD. ] TRANSFORMATION OF ARTEMIA. 499 do we find males in the degraded generations of A. salina already hear- ing the characters of Artemia milhausenii, and which live in the most saline water. However, we can plainly notice that in the salt ditches and in very small salt lakes drying up in summer, that the males of Ar- temia appear in immense numbers at a certain time of the year, and at a certain concentration of the salt water, as I observed it at a compara- tively rapid evaporation of the water of the salt-water basins at the time of continued drought. Here we have to give ourselves the solu- tion of the question about the change of this physiological function in consequence of the distribution of generations of a species in another element, together with a certain variation of other functions, and of the animal organism. Referring to this I mention but one of the sides, to which variety b. of A. salina inclines to the genus Branchipus. This variety has with the species the other structures in common, with the exception of those less noticable aberrations depending upon the element, 7. ¢., principally from the lower concentration of the salt water, together with their own organization. So, for instance, are the gill- saes in the variety a little smaller, but especially narrower than in the species; likewise in.the body more of a gray than a reddish color, and more transparent. This form most closely approaches the variety of Branchipus ferox of our salt ditches, but perhaps it is the radical form of B. ferox and B. spinosus. Consequently we have, therefore, here three closely allied forms of Artemia: A. salina, A. salina var. a., and A. salina var.b. The species A. salina inust justly be regarded as a double form, consisting of A. salina and its first variety (var. a.), as these two forms in long past times must have originated by division and formation of races of their generations from one for both middle forms. Regarding the second variety (var. b.), it represents a form originated from A. salira, and be- came distributed in salt ditches of lesser salt capacity, and it is likely that also a similar offspring of the second variety exists. These three forms, however, have so many different characters that they in any case can be recognized as varieties amongst themselves. We find such cases also in other widely-distributed species of Crus- taceans,' for instance, in Cyclops bicuspidatus Claus, and especially in Cyclops odessanus n. sp., where two (Cyclops bicuspidatus) or still more (C. odessanus) near, but still differing forms under certain external con- ditions, each living in either its peculiar pond in one and the same, or also in different water basins, and where each under certain external conditions or at another season of the year obtains preponderance at least in the number of specimens. But the forms of Artemizx have the preference before other Crustaceans, inasmuch as the surrounding ele- ment includes less complicated conditions, which by the observer can be kept under better control. Among the forms of Artemis we may regard A. milhausenii as one of the most retrogressively developed ones; but as one of the most pro- gressively developed forms we have that which I provisionally call variety b. of A. salina. Parallel to this A. milhauseniti lives in very saline water, near the self-deposition of salt, or near the same (about 23° to 25° Beaumé), but variety b. of A. salina lives in comparatively less saline water (4° B.). ; Our A. salina does not fully agree with that examined by Joly,’ 1 Consult my paper in the ‘‘Schriften” of the neorussian Society of Nat. 1875, vol. Il], 2d part. 2 Joly, Sur Artemia salina, Annales des Sc. Nat. 1840. 500 GEOLOGICAL SURVEY OF THE TERRITORIES. occurring in the south of France. Our A. salina is rather a middle form between A. salina Joly and our large race of A. salina (var. a.). The considerably prolonged furea and the rather thin female claspers (males were unknown to Joly) of A. salina Joly recall these parts in the mentioned variety, but the body-length and the proportional length of the abdomen agree with the same characters of our A. salina. The mean concentration of the salt water Joly mentioned for his species corresponds better with the mean concentration for our variety a. of A. salina. Besides, according to the drawing of Joly, in his Artemia salina the sixth apodous (Joly’s fourth) segment of the abdomen is a little longer than the seventh, but in our A. salina the sixth apodous abdom- inal segment is usually a little shorter than the seventh; still it be- comes longer only at too high concentration of the salt water and also in younger stages of the specimens. In mature specimens of our A. salina is the sixth segment especially longer when the concentration of the salt water does not change from year to year, but in a shorter time, as, for instance, from spring towardsummer. The relative length of the sixth and seventh apodous abdominal segments in our A. salina may also serve as a measure for determining the age of already nature speci- mens at a given concentration of the salt water, since the seventh apo- dous abdominal segment prolongs with the age, and when this segment in heightened concentration of the salt water, also in mature specimens, ‘remains equal with the sixth or shorter, it indicates that sexual ma- turity appears under such conditions a little earlier than the full devel- opment of the body-parts. In variety a. of our A. salina is the sixth apodous abdominal segment generally somewhat longer than the seventh, which corresponds with the illustration of Joly and the usually not sexually mature specimens of our A. salina. The male claspers of our A. salina are, as alluded to above, of the same form as figured by S. Fischer for his A. arietina (Middendort’s sibir. Reise, vol. II, part 1, Pl. VII, fig. 32), but the termination of the upper antenne separates, according to the description and illustration of S. Fischer, this form trom Artemia salina. Concerning the diagnosis of A. salina Grube (Branchipus salinus Grb.) it remains unknown wherefrom Grube took the statement, that in this species there are eleven bristles on the edges of the terminal plates (lobus tarsalis Grb.) of the legs. The lobus tarsalis Grb. is the palette of Joly, as expressed by Grube, but Joly points out 30 to 38 bristles on each such plate. I believe that this is a mistake in Grube’s diagnosis, and that Grube counted eleven bristles from Joly’s illustration on an- other foot-plate of Art. salina, that is, on one of those plates which Grube! calls himself lobt tibiales. This mistake in Grube’s diagnosis can be sufficiently cleared up by the comparison of the description and illustration of Joly with Grube’s diagnosis and synonyms, which Grube mentions for the terminology of these lobes in these animals after various authors. I wonder that I have not hitherto succeeded in finding that species which 8S. Fischer described from the neighborhood of Odessa? under the name of Artemia arietina. The principal and Very great difference of A. arietina consists, according to Fischer, in that the terminations of the first pair of antenne in this species are divided into two branches, whereby the end of one branch bears two olfactory bristles, but the end of the other bears two prolonged bristles, while in all Artemize collected 1“¢Bemerkungen tiber die Phyllopoden,” Archiv f. Nat. 1853, p. 141. 2 Middendort’s Sib. Reise, Vol. II, part i, pp. 156 to 157. PACKARD. ] TRANSFORMATION OF ARTEMIA. 5OL by me here and in the Krimea an entirely different ty pe of structure of the first antenne predominates, there being on the scarcely biramous end of the antenne of the first pair four olfactor Wy bristles and three rather long bristles. Also at my visiting the Krimea last year (1876) I found the same Artemize as near Odessa. It is the same Artemia salina with its two forms (a smaller, the Artemia salina, and a larger the variety a. of A. salina), and moreover with its ditferent variations, 2 as they depend upon the different concentrations of the water in a Known salt lake (the specimens with the characters of variety b. of A. salina and those with the characters of A. milhausenit). Beside the lake near Eupatoria I also visited five other small lakes near Sebastopolis. Out of one of these lakes, the second on the Chersonesis and at the same season of the year, Ulanin! obtained Artemiz and, as communicated to me by the author himself, alcoholic preparations already rather injured, which he deseribed as a variety of A. arietina Fischer (Gr. arietinus Grb.). 8S. Fischer described his A. arietina also from alcoholic speci- mens, but we ought from all Crustaceans, Artemide the least, not to describe them after alcoholic specimens, as in them especially the num- ber and the relation of the postabdominal segments remain concealed from any observer who does not succeed in obtaining live material. Unhappily also the systematic deseription of the Artemia and Branchi- pus has hitherto remained still the same, as founded in literature by descriptions from alcoholic specimens. Such misrepresentations arise from this, that, for instance, in one species, Artemia salina, the second antenne of the male, while in another species, Artemia milhausenti, under the same name, the second antenne of the female have been described (cornes céphaliques, Milne Edw. Hist. nat. des erustacées), as the males of this species were not yet known,” about which I shall speak further below. For those uninitiated in Artemia and the singularities of its literature, such diagnosis may form a source of many errors, which I have elsewhere endeavored to clear up.° 2.— Generations of Artemia salina Milne Edie. receiving the characters of Artemia Milhausenti Milne Haw. Artemia mithausenitt has been described by authors under various names (Branchipus milhausent Fischer von Waldheim, Art. salina Rathke, Art. miihausentt S. Fischer) from alcoholic specimens, and therefore we find various contradictions and inaccurate accounts in the descriptions of this species. Other authors (Milne Edw., Grube) bor- rowed accounts from the former for the diagnosis of this species. If the forms occurring in nature and those obtained by a certain domesti- cation from A. salina and its first variety (varietas a.) agree with those which have been described by the authors under the name of A. mil- hausentt and synonyms, or, better expressed, if there is in a state of nature no other A. milhausenit than the degraded and modified form of A. salina, which receives with the generations after a certain time and by heightening the salt capacity of the salt lake the characters of A. mit- hausenit, then A. milhausenti, owing to the manner of its origin and the . “Schriften der kaiserlichen Ges. der Liebhaber der Nat. Anthrop. und VOolker- beschr. Moskau. Vol. V, part i, page 96. 2C. von Siebold, Beitriige zur Parthenogenesis der Arthropoden, 1871, p. 209. 3 Consult my paper: Explications relatives aux différences qui existent entre PAr- temia salina et VArt. milhausenii-et entre les genres Artemia et Branchipus. Bi- blioth. Universelle et Revue Suisse. ‘Archive des sciences phys. et natur. Geneve.” Vol. 57, No. 224, 1876, pp .358 to 365. 502 GEOLOGICAL SURVEY OF THE TERRITORIES. infirmity of its characters, in which, however, it differs from the nearest forms, as one species differs from another species, does not represent an independent or original species. At constant high or little changed concentration of the salt water, this form is able to produce entire series of generations with the characters of A. milhauseni, like an original species. Even if the generations of our form with the characters of A. milhausenti are qualified at a certain behavior of the surrounding element to preserve their distinctive specific characters, then these generations only represent a degraded and modified torm of A. salina, or, indeed, two closely allied forms of A. salina, of which one represents the changed generations of A. salina, the other the changed generation, of the first rariety (varietas a.) of this species. In a short treatise in Zeitschrift f. w. Zoologie, Vol. X XV, first sup- plementary part, I have spoken of the changes of the generations of A. salina produced by heightening the salt-capacity of the water in nature and by artificial domestication, whereby they received the species char- acters of A. milhausenit. Without repeating the same, I will only point out that, together with the modifications of the postabdomen of A. salina the other parts also gradually changed in the direction toward tenia milhausent?, t. €., the postabdomen ‘became more slender and longer, the female clasper S narrower; the leg-parts also changed them- selves, whereby the number of bristles and fimbriate spines of the leg- lobes lessened, and the gill-saes (Claus) changed from elongate to oval, thus comparatively increasing their size. We obtained finally all the peculiar characters of A. miéiausenii, as they were described by the authors. The specimens with the characters of A. milhausentt in the Kujal- nitzki salt lake justly represent a degraded and changed form of A. salina and its first large variety (a.), for that we also distinguish two different forms of individuals with the characters of A. milhausenii. Some correspond with the specimens of the species, others with the mentioned variety of A. salina. Even if the characters of the species and this variety of A. salina, through degradation of their individuals, become somewhat obliterated, it is nevertheless still possible to distin- euish individuals originating from this or from that form. Those cor- responding with A. salina have about 10™ length, those of the men- tioned variety are about 12™™ in length. In the former the post- abdomen is a little shorter, and the posterior or apodous segments is shorter than the double lew. gth of the anterior part of the body, and is in proportion to it on the average as 8 to 5, but in the latter the posterior part of the body is equal to twice the length of the anterior part, ora lit- tle shorter, in the proportion in the latter case of 9 to 5. In both species this relation moreover depends upon the age of the already sexually ma- ture individuals, since in already olderones the posterior partof the body is longer. Moreover, the former have a less dark red color, and their rounded abdominal end is somewhat broadened and as if flattened in the direction from above downward, but the latter have a more dark red color and the abdominal endisless broadened, only rounded. In this way the specimens of A. milhausenit have two forms, but the difference of their characters is scarcely sufficient to regard one of them as a true race in relation to the o:her, and the less so, as the deviation of the indi- viduals of the one or the other category on one or the other side, accord- ing to age, even at the time of sexual maturity, allows some transitory stages to be recognized between them. It is only apparent that some represent a degraded form of A. salina, but that others represent a de- graded form ot variety a. of A. salina. It is necessary to remark, that PACKARD. | - TRANSFORMATION OF ARTEMIA. 503 the former already at 20° Beaumé represent a just as far degraded or retrograded form as do the latter at 23° or 24° Beaumé, and that the former occur principally in one, but the latter in another, now cut-off part of the Kujalnitzki salt lake. For better distinction I shall call the former the smaller, the latter the larger form with the characters of A. milhausenit. Did this Artemia, with the characters of A. milhausenii, one form of A. salina, change by the influence of the surroundings, or one by the influence of the same in the development-retarded form? To this ques- tion the characters themselves, and the course of postembryonal devel- opment of this modified and also in development retarded form, answer. Not ouly characters show themselves in this form peculiar to the younger age of A.salina, and originated from retarded development, but also newly acquired to the surrounding adapted characters. The young individuals of A. salina and its variety have, as is known, in the begin- ning no furca, but it develops much later. This circumstance testifies that in adults with the characters of A. milhausenii no furca has been formed, owing to retarded growth. But we must consider that in those transitory forms between A.salinaand A. milh., which in mature and old age have a little-developed furea, with a very small number of bristles, have, in still young age, just before the appearance of sexual maturity, and shortly after the same, a still more developed furea, with a larger number of bristles preserved, than tn old age, during which this part at one and the same salt capacity of the water more degrades. This phenom- enon can still be better noticed in the domestication of suecessive gen- erations of A. salina in salt water of gradually increased concentration, wherein that period, during which the furea mostly develops, shortens with each following generation, the development of the furca becoming a weaker one, appearing tn shorter time-spaces. It is important that this period includes the space of time immediately before and partly also after the appearance of sexual maturity, in the beginning of mature age; also in those specimens in nature in which in later, mature, and old age altogether no furca exists, a little developed appears in said pericd, partly with bristles, or only in later generations, by the inilu- ence of the surroundings in the same direction, this phenomenon of char- acters of higher original form is more and more obliterated. Ail these phenomena prove that the absence of the furca in the forms with the characters of A. milhausenit depends upon retarded development of the organization of the generations, rot only from the appearance of sexual maturity still before the full development of the body parts, but also from the immediate influence of the salt water of higher concentration, at which the appendages just beginning to develop became as if atro- phied. There are many similar examples of retrograde development of the form and of the individual. The greater length and slenderness of the postabdomen in the speci- mens with the characters of A. milhausenii compared with the part in mature and still more in younger A. salina, proves with certainty that the organization of such specimens in this relation depends almostentirely upon the immediate influence of the element, but not upon an indireet influence, 2. ¢., from the mechanical pressure of the salt water, and the later appearance of sexual maturity, and not from the retained growth and the appearance of sexual maturity before the complete development of the body-parts. Had the postabdomen of the specimens with the char- acters of A. milhausenit formed as a consequence of retarded growth and in comparison to A. salina earlier and before the full development of the body-parts ensuing appearance of sexual maturity, this postabdo- 504 GEOLOGICAL SURVEY OF THE TERRITORIES. men would have remained comparatively short and stout in the conduct of these parts im the young A. salina, in which the furea is not yet de- veloped, or it would be in any case shorter and stouter than in the mature A. salina. Ladmitthatin further degradation of the generations with the characteristics of A. milhausenii the postabdomen ¢ could have become even, if not shorter, yet less shorter, than in the mature A. salina, but Lonly speak of what has really been the case in these specimens. The circumstance that at a higher salt capacity of the water, the growth of the degraded specimens of A. salina is going on slow, and the sexual matn- rity appears in time late, gives its postabdomen the chance, as if in contrast with the degrading influence of the element to prolong, and the latter perhaps also retains the prolongation of the abdomen, espe- cially in combination with the heighteped temperature, which also, according to the time, awakens the sexual maturity earlier. In A. milhaus enti, described by Rathke! under the name of A. salina, is the posterior part of the body, consisting of apodous segments, also shorter than the anterior part, although the ‘description, illustration, and figures of this author stand in great contradiction to each other. Irom the de- scription of this author it follows that this Artemia in summer lives in a concentration of the salt lake reaching self-deposition. Liven if the postabdomen in our specimens with the characters of A. milhauseni is larger than in A. salina, there is nevertheless in transitory forms, in which the degradation did not yet reach the extreme limits, a post- abdomen somewhat longer than in the specimens which in the further generations live at a higher eoncentration, lacking the fureca already, as is especially noticed in the summer gener ations. The length and slender- ness of the postabdomen prove in any case, especially in our speciinens with the characters of A. milh., the dependence of the organization of these specimens upon the immediate influence of the surrounding, de- pendent upon the retarded development aud sexual maturity appears earlier than the full development of body-parts, since on the whole the postabdomen of these forms is longer and slenderer than in the young, and also even in the mature forms cf Art. salina. Contrarily the gill-sacs also prove the retarded developmens of A. milhausenit if they are also in their development simultaneously adapted to the demands of the surroundings. ‘That is, in young specimens of A. salina exists a period in which their gill-sacs have nearly the same form as in the mature individuals with the characters of A. milhausentt. Likewise the gill-saes are in the mature individuals with the characters of Art. milh. larger than in mature individuals of A. sulina, especially in relation to width and in the comparison with the length of the body in these or those individuals. But the young individuals of A. salina now have larger gill-saes than the full-grown ones, there being a period in their development in which the gill-sacs are in length and width so in proportion, as is the case in ma- ture specimens with the characters of A. milhausenti. This apparentiy points to the exclusive dependence of the gill-sacs upon retarded devel- epment of the form in the latter specimens, but this only seems to be so. Jf we domesticate generations of A. salina in gradually diluted salt water this period appears, during which the gill-saes of the young Artemia have the measure of the gill-sacs of the Tae ee specimens with the characters of A. milhausenii, always earlier, i. e., it approaches the beginning of development; in the domecmeian of these generations in an opposite direction, this period always appears later; ¢@. e., it ap- 1H. Rathke, Beitriig. zur Fauna der Kvim. pp. 395 to 401. PACKARD.] TRANSFORMATION OF ARTEMIA. 505 proaches the end of the development, so that the young specimens of one and the same age, but, from a different element, do not correspond in this relation, and the younger age of the former concurs with the later age of the latter. Since the whole development of these or those speci- mens proceeds similarly, so must the development itseif depend upon the immediate influence of the surroundings, after which the organism of these or those forms develops, whereby that in the generations sums up what the external conditions in them produces; and what they as a consequence of the influence of the surroundings acquire. Here we must imagine the transfer of the course of development of a single in- dividual upon the course of development of particular animal forms. From all this it results that the gill-sacs of the young individuals of A. salina are in a certain age similar to the gill-saes of the matwre individ- uals of A. milhausenti, but the gill-sacs of the young individuals of this latter species are at the same period still larger, and obviously represent an addition in the organization of this form in comparison with A. salina, and a result of the influence of some force. This force was the sur- rounding element of a certain composition, that is, the large salt capa- city of the water alone, or in combination with heightened temperature. Hence, we see that the gill-sacs in A. milhausenti, together with some other parts of the body, testify to the retrograde development of this form under the influence of the surroundings as well as of the immedi- ate influence of this element. It is worthy of remark that the fact that the adaptation to the element is accompanied by a retarded development of the generations, as in other cases the adaptation to the element in these animals is accompanied by a progressive development of the gen- erations; in another element by the, as regards this species, typical de- velopment of the body parts and sexual inaturity. In the one and the other case the element effectuates a change of form in a direct and in- direct manner. Of course, nature effects this in a great measure, not so much by the change of the element as by distributing generations of a species in a highly varied element. Touching now the question, whether the specimens with the charac- ters of A. milhausenii, which in the course of several years and a com- paratively small number of generations issued from A. salina in the Kujalnitzki Lake, at a gradual heightening of the salt capacity, do repre- sent a species, or at least a variety, I must answer in the negative. If it turns out that the actual Artemia milhausenii of the authors, according to its structure and origin, is equal to the degraded specimens of A. salina, then it has no right to be regarded as a species proper, yea, not even to be a variety of A. salina, or of any other species, since the man- ner of its origin under the mentioned conditions contradicts the prevail- ing conception of species and race. Species and race possess a compar- atively great endurance of characters, and must originate in consequence of more or less widely spread distribution of generations of their pre- ceding or contemporary forms in a differentiated element (without natural selection or with it), but not owing to the modification of the surround- ing element in a given locality, and moreover in a brief space of time, in the course of perhaps four years.! Even if the change of the element at a certain rate of slowness can favor the change of form, the main cause of their origin must, neverthe- 1The lowest organisms appear, by certain changes of the surroundings, in an incon- siderable space of time to represent definite series of forms, which we are accustomed to hold as species. The beginning of my papers in this direction relative to the low- est organisms, forms my article in the ‘‘Schriften” of the Neorussian Society of Nat- uralists, 13876, vol. iv. 506 GEOLOGICAL SURVEY OF THE TERRITORIES. less, ie in the disposition of the generations to distribute themselves in much varied elements, that is, to distribute themselves beyond the limits of that element, at which, in the generations, the typical characters of the species preserve, regardless as to the causation of such distribution, by increased augmentation of the individuals, or of such external influ- ences, like modification of the element in a given locality. Our individ- uals with the characters of A. milhausenti actually represent the degraded and modified generations of A. salina, by the itself rapidly changing ele- ment which also influences the Artemie living init. Similarly, like cer- tain annual species, which with their generations are much distributed, according to the seasons of the year, represent rather great differences in spring and summer forms. As the most extreme generations of the seasonably distributed species deviate from their species-type toward the nearest allied forms, as is seen, for instance, in Cyclops brevicaudatus Claus, and Daphnia magna, Leydig, var.,! so likewise deviates Artemia salina with its generations at the most extreme limits of endurable concen- tration of the salt water toward the forms allied to them. But there is a great difference between these phenomena. Artemia salina changes during the course of several years in the direction toward A. milhausenii, passing through a comparatively large series of generations, and whereby we, in comparison, finally obtain a far greater modification than any hitherto known deviation in the generations distributed sea- sonally. If there actually exists in nature a self-sustaining species, A. milhausenti, like an A. koeppeniana Fischer, besides the degraded gen- erations of A. salina and similar forms, then such degraded generations of the highest species of Artemiz represent transitory forms toward the lower species of this genus, and indicate the element under whose influ- ence the latter originated. This element must be a salt water of great concentration, together with heightened temperature. It is possible that in long-continued duration of the salt-lake element peculiar to the tow- est Artemiz, the degraded generations of the higher species of this genus still more degenerate, rendering their characters more permanent, but the forms themselves more independent, even it the principal condition of the origin of independent forms consists in the distribution of genera- tions of these forms producing species in a heterogeneous element, but not (or less) in the modifications of the element of a known district or of a certain water-basin. It seems to me that, with a very gradual increase ot the concentration of the salt lake, the species populating tt will rather die off in this location, than producing a new self, sustaining itself with the element modifying species. In view of such phenomena a strict scrutiny of such lowest Artemize as A. milhausenit is unconditionally necessary; all the more, since these Species were described by the authors for the greater part from alcoholic specimens, and moreover at a time in which the modifying effect of the salt water upon the Artemiz was yet entirely unknown. To solve the question, whether A. milhausenii exists as a Self-sus- taining species, I visited during the middle of July, 1876, the Krimea and examived specimens of Artemiz: from that salt lake, which is located near the Tatare village Sakki on the way between Hupatoria (Koslov) and Simpherpolis, from which the authors (Fisher von Waldheim, H. Rathke, 8. Fischer), who described the Artemia mi/hausenti obtained their Artemiz. I saw that in this lake occurred already at the self-depo- sition of salt specimens fully answering the descriptions of Artemia 1Consult my paper in the “Schriften” of the Neoruss. Soc. of Naturalists. 1875. Vol. iii., Pp. 18 to 44 and 206 to 214. PACKARD.] TRANSFORMATION OF ARTEMIA. 5O7 milhausenii of the authors (exclusive of their mistakes), and likewise oe- curred in it at the same time specimens of the transitory form toward A. salina Milne-Edw., whose specimens here were in various degrees of degeneration in the direction of Ar/emia milhausenii. They were all such specimens as those found by me at the end of summer, 1873, and middle of summer, 1874, in the Kujalnitzki Lake, near Odessa, that is to say, partly complete, partly not fully changed, specimens in form, known under the name of Artemia milhausenii. ‘Lhe circumstance that in the very saline Sakki Lake, there still occurred also in the middle of July * many specimens of the transitional form between A. salina and A. mil- hausenii, is explained by the fact that the preceding winter in the Krimea was very snowy, that the water in the salt lake in spring became very diluted, and that the specimens and generations of Artemia salina had to change rapidly in one summer, therefore many specimens did not succeed in fully transforming in this one summer. (Only at very gradual increase of the concentration of the salt water have the following genera- tions of Artemia salina in all their specimens the form of Artemia mil- hausenii, as observed by me in the course of several years in the Kujal- nitzki salt lake near Odessa.) After several days of great drought and iInerease in the amount of the deposited salt in the Sakki Lake, f could not find a single individual of Artemia. I have to state that the speci- mens of Artemia in this lake belong to those two races of Artemia sa- lina, which live in the neighborhood of Odessa in the Kujalnitzki salt lake. The smaller individuals of this much distributed species answer to Artemia salina, changed in the known manner, but the larger indi- viduals answer to variety a. of Artemia salina changed in the same di- rection. It would here be important to know what is really wanting in the degraded generations of Artemia salina, in order to possess all the char- acters of Artemia milhausentt Autorum. Contrary to the diagnosis-of this species (A. milhansenii of Milne- Edwards), we in our generations notice but the one difference, that on the female claspers of our individuals toward the middle is found a small protuberance or broadening, Milne-Edwards not mentioning this (of course in the females, as the males were yet unknown at that time). These words of Milne-Edwards do not correspend with Rathke’s state- ments, who described this species under the name of his Artemia salina. We see from Rathke’s drawing and description that the second antennue of the female of this species has two broadenings divided by a trans- verse ring, which the author regards as the two first joints, whereby a broadening occurs near the base, another one in the middle of the an- tenna, which answers the same as similar broadenings in our temale specimens with the characters of this species. In comparing Artemia milhausenii with A. salina we must observe that in Milne-Edwards’s diag- noses (Histoire naturelle des crustacées, Vol. III) the second antenne of the males of A. salina, and the second antenne of the females of A. milhausenti, of which latter the males were yet uaknown, have been described, as already stated above. For these determinations in both diagnoses (cornes céphaliques) Milne-Edwards omitted to give the necessary explanation. Opposed to this the description of Rathke gives the following differ- ence: He says that in this species the upper antenne are four-jointed, whichis very doubtful, since in the forms of this genus and in Branchipus the upper antennee are not jointed, but we only observe after a number of subsections similar to faint transverse rings, which should not be 1 Midderdorf’s Sibirische Reise, Vol. II, part i, pp. 155 to 156. 508 GEOLOGICAL SURVEY OF THE TERRITORIES. taken for articulations. Furthermore, according to Rathke, this species has, besides the upper lip, no other oral parts, while S. Fischer,! in com- pleting the description of this species, describes beside the upper lips, also other oral parts (upper and lower jaws), which differ in nothing from the same parts in other Artemis. In our specimens with the characters of A. milhausenit, these parts fully correspond with the description given by 8S. Fischer. Such a great contradiction between the authors awakes a doubt whether they had todo with the same forms, thus rendering the determination of this species difficult. Likewise Rathke does not men- tion in this species the existence of the posterior branchial lobes, while he dwells at length upon the gill-sacs, as if the former were not existing at all. Butin reality Rathke probably did not see them at all on account of their transparency. These branchial lobes exist in our specimens (and those from the Krimea) with the characters of Artemia milhausenti, and 8. Fischer gives an illustration of them with his description of Artemia képpeniana. On the contrary, in Rathke’s description there is yet a dif- ference in the length of the abdomen. In our individuals with the char- acters of Artemia milhausenii, the posterior part of the body, consisting of apodous segments, is longer than the whole anterior part, being to it in proportion at least as eight to five; but in the specimen described by Rathke the pesterior part of the body is shorter than the anterior. However, we can with certainty say of Rathke’s description, what length the posterior part of the body had in the specimens described by him. From his words itis to be assumed that Rathke calls the whole posterior part of these animals (without the first two apodous segments of the abdo- men?) a tail. The comparative length of this tail he compares with the tail (postabdomen) of the scorpions, and shows by the illustration that the posterior part of the body is nearly + shorter than the an‘erior part, while in the stated measurements he has such figures as surprise me by their disproportion, and according to which the tail would be two and a half times shorter than the anterior part of the body. The latter can only be called a misprint; it remains unknown, however, how the omission of oral parts (excepting the upper lips) and the posterior branchial lobes can be explained in Rathke’s descriptions. If the degradation of this form had proceeded so far, that with them these parts were not developed at all, it would have been different from the form examined and more completely described by 8. Fischer. 5S. Fischer, however, calls the tail of the form examined by him, long, which expression! H. Rathke does not use, but the termination of the post- abdomen, according to Fischer’s drawings, differs from the termination of this part in Rathke’s drawing, not showing any broadening. It is possible that Rathke and Fischer had different forms in possession, whereby Rathke’s form is identical with the very degraded generations ot Artemia salina, or corresponds with them, while Fischer’s form is a degraded form of the larger variety a. of Artemia salina. Finally, on the other hand, Grube’s’ diagnosis of this species aiffers from our generations with the characters of Artemia milhausenti, in having on the terminal lobe (lobus tarsalis Grb.) not about 17, but about 25, marginal bristles; it is possible that here Grube borrowed the num- ber of bristles from Rathke’s drawing, who drew on his small illustra- tion about such a number of bristles, only saying in the description long, but does not take this expression in his diagnosis of Artemia salina. 2**Bemerkungen tiber die Phyllopoden” in Archiv fiir Naturgesch. 1853, p. 145. He correctly remarks, amongst other things, that Rathke could not have observed the very tender and transparent posterior branchial lobes in so old alcoholic specimens. PACKARD.] TRANSFORMATION OF ARTEMIA. 509 that there were many bristles. On Rathke’s drawing are 18 such bristles, and even if there had not been more this makes no great dif- ference, especially in view of the fact that the specimens obtained by Rathke, from a salt lake in comparison with ours, could have been more degraded. I must here add that in our Artemia salina there are some thirty bristles on the terminal lobe of the leg (?); in variety a. of Arte- mia salina there are some thirty-three marginal bristles. Had we not had in the Kujalniker Lake in 1874 a second inundation, the genera- tions with the characters of Art. milhausenti would certainly have proved more degraded in relation to this, as there stronger concentrated salt water would have remained in the lake. I therefore cannot, without excluding the possibilty of the existence of aself-sustaining species of Artemia milhausenti, regard the degraded generations of Artemia salina obtained as a species proper, aud even not then, if such degraded generations exhibited all the characters of Artemia milhausenii: the characters of A. milh. at a certain modifica- tion of the element in the course of several years or also by domestica- tion of several successive generations of Artemia salina mM a correspond- ingly changed element. After all I hope nobody will think that I endeavor, with the aid of modifying the element in the domestication of animals, to produce from one species one or more new species. Everywhere I have sought to obtain the intermediate transitional forms between the nearest-allied species, and I approached myself in a moderate degree the characters of the actual species, but we cannot regard such forms as independent ones which have by domestication received characters of unknown con- staney (in nature), and which we obtain by changing the element during domestication of several generations. It is possible that in earlier times and even also at present in different other localities, as species and an- cestors of our present species such middle transitional forms among the closest allied forms live; nevertheless these forms, resulting from domestication, will neither yepresent independent species nor varieties, as incipient species, but they only show the cay in which the characters of a given species combined and which way man, with bis zoological ex- periments, especially with the present means of science, cannot fully follow. Should we succeed in producing, with the aid of domestication, a form possessing all the characters of a species existing in a state of nature, then this form will differ from the realin nearly the same way as the best picture will differ from the original. This would be like making concessions to the present conception of species. Owing to the stated facts it seems to me that our present species can be artifically pro- duced by man, only this does not happen with the aid of artificial do- mestication, but by adaptation of physico-chemical factors. We should never forget that in nature the characters of a species have a relative stability. 3.—The characters of the genera Artemia and Branchipus. The characteristics of the genera Artemia and Branchipus are demon- strated by many authors, owing to an insufficient knowledge of the characters of the genus Artemia, in a confused and even wrong man- ner. Already in 1853 had Grube made! his protest against the stability of the genus Artemia, seeing that Artemia differs only from Branchi- pus by quasi- negative characters; he also saw the necessity of forming 1Grube, Bemerk. iiber die Phyllopoden in Arch. f. Nat. 1853, pp. 182 to 134. 510 GEOLOGICAL SURVEY OF THE TERRITORIES. from Artemia a proper group or a subgenus of the genus Branchipus, like Branchipus proper and Polyartemia. Dr. Grube, nevertheless, gave in reference to the then known facts of Artemia a mistaken char- acteristic of his subgenus Artemia, saying, amongst other things, that it possessed six apodous segments and that the short furca was only bristled at the ends (appendicibus caudalibus brevibus, apice tantum setosis .... ). Relative to the number of apodous segments of the abdo- men, Grube repeated the statement of those authors (Joly) who in Ar- temia did not take into consideration the first two apodous segments of the abdomen, bearing the external sexual parts. Without these two first apodous segments of the abdomen Artemia has really six apodous abdominal segments, but since the external sexual organs answer mor- phologically to modified limbs, we only in this sense can count in Ar- temia six segments of the abdomen; like Branchipus in this case it would have but seven and not nine segments. But Grube in this sense does not count six apodous segments in Artemia, as he demonstrates nine apodous segments for his subgenus Branchipus, and we can see from the general diagnosis of the genus Branchipus (IL. ¢., p. 136), that those segments, bearing the external genitals, were taken in with the apodous segments of the abdomen of his genus Branchipus, i. e., ineclu- sive of Artemia and Polyartemia. But, in fact (as mentioned above in the completed description of Artemia salina) the species of Artemia have eight apodous abdominal segments, the first two of which bearing the external genitals, and of which the last is nearly twice as long as the preceding and is homologous with the two last apodous segments of the species Branchipus, but the Branchipode have nine apodous abdominal segments, of which the first two also bear the genitals, and of which the last, located before the furea, is not longer, but usually shorter than the precedin oon In regard to the position of the fureal bristles in Artemiw I have already ‘stated above that in our forms of Artemia the bristles are not only at the end but-also often on the margins of the furca, and that these bristles often occur also in great numbers, the furea assuming, as in variety b. of Artemia salina, a plate form. If we ask now whether all species of Branchipus really possess nine apodous segments, of which the two last ones are homologous with the prolonged last segment of Artemia, then it seems indeed to be the ease. Only Branchipus stagnalis could form an exception. At least from the statements of the authors? the number of apodous abdominal segments (whether eight or nine) cannot be inferred with certainty, and I myself had not hitherto occasion to examine Branchipus stagnalis. Concerning the question whether all the species of the genus Artemia have eight apodous abdominal segments, and whether in all the last segment. is prolonged and homologous with the last two abdominal 1JIn my paper in Zeitschrift f. w. Zool., vol. xxv, supplement part, appearing under the title “Ueber das Verhiiltniss der Artemia salina M. Edw. zu Art. milhausenii M. Edw. und dem genus Branchipus,” I must add a correction relative to the propor- tional length of the last abdominal segments in Branchipus. There it says: ‘‘ Branchi- pus has nine last apodous segments, of which the two neighboring segments show only a small differencein length among themselves” (1. cit., pp. 106 and 110). Tought to have said: “ Branch: pus has nine apodous abdominal segments, of which the last, situated before the furca, is not longer but usuaily shorter than the preceding seg ment.” ?Leidig, ‘* Ueber Art. salina und Branch. stagnalis.” Zeit. fiir w. Zool. 1851, p. 281. Spangenberg, ‘ Zur Kenntniss von Branch. stagnalis” in Zeit. f. wiss. Zool. 1c76, pp. 8to 9. Supplement part. Claus, ‘‘ Zur Kenntniss des Baues und der Ent- wicklung von Branch. stagnalis und Apus cancrif.” Goettingen, 1873, p. 14, Tab. V, fig. 10. PACKARD. ] TRANSFORMATION OF ARTEMIA. 5 li segments of Branchipus; of this no indications occur in literature. That Artemia salina observed by Joly has eight apodous abdominal segments with a very prolonged last segment can be seen from Joly’s illustrations, and also from this, that he ‘counts six apodous abdominal segments without including the two first apodous abdominal segments which bear the external sexual organs. According to Rathke, who ob- served alcoholic specimens of Artemia milhausenii (Art. salina Rathke), the postabdomen is indistinctly divided into segments; he did not indi- cate how many segments there are. Our degraded generations of Artemiasalinawith the character of Artemia milhau usenii have just asmany apodous abdominal segments as Artemia salina, only the articulation is more distinet. In the description of Artemia ar vetina S. Fischer and Artemia kippeniana 8. Fischer nothing was said about the number of apodous abdominal segments. Grube very incorrectly states the num- ber of apodous segments in Artemia as being six, incorrect, for because right after in another diagnosis he correctly mentions in his subgenus Branchipus nine apodous segments, thus showing which segments of the abdomen he considers as apodous. Joly gave oceasion for this conclusion in omitting the two first apodous segments of the abdomen, whichin Artemia, as wellasin Bra nehipus, bear the external sexual org gans. In the other mostly examined alcoholic specimens of Ariemia, the artie- ulation is not very plain tosee. In this regard Branchipus oudneyi Lie- vin (Artemia oudneyt Baird’s) deserves at etention, under which name an Artemia from a salt lake in Africa was described by Dr. Lievin.! This African form has in the illustrations eight apodous abdominal segments, of which the first only bears the external genitals, the last being short, at least shorter than the preceding. Although this form, asin Artemia, has eight apodous abdominal segments, it can nevertheless in this pro- portion be included neither with the genus Artemia nor with the genus Branchipus. But the illustration now does not correspond at all with the description of the posterior part of the body of this Artemia. It is said in the description? that the specimens examined had laid a long time in alcohol, and that therefore the number of abdominal seg ments could not exactly be determined; that the abdomen of some specimens answered as if to one segment only, Ww hile in others four could be distin- guished, again, in others five segments ; but from the fifth in the others they could not be distinctly seen. Dr. Lievin considers the presence of eight abdominal segments as probable. Here the author understands as abdomen only the whole of the apodous abdominal segments. hs j . : ‘ —. oy" | i TT LY i uf | i Fig 3. By a et Ws, i : Packard, del. T Sinclair & Son, lith. Pinla. 539 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE VIII. ARTEMIA GRACILIS Verrill. (From Utah.) Fic. 1. A dorsal view of male head and claspers; oc, ocellus; at, Ist antennaz; at’, 2d antenns or claspers. Fie. 2. An anterior leg. Fie. 3. A middle leg. Fic. 4. A last leg. Fig. 5. End of abdomen. Drawn and details filled in with camera lucida by the author. Plate VIII 6 Bankr eh SS Qh a ao) “4 rey > 1G olo ~A.S Paclxar-d, del. 532 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE IX. BRANCHINECTA PALUDOSA with details. 1. Male, at, first antenne ; at’, claspers, or second antenne ; p, penis (gonopoda). 2. Female. This and Fig. 1 enlarged several times. Fig. 3. First foot of male, * 50 diameters. 4. Second foot of male, x 50 diameters. Fig. 5. Tenth foot of male, x 50 diameters. Fic, 6. End of abdomen, with the caudal appendages. Figs. 1 and 2 drawn by J. H. Emerton for Bessels’ report on the Voyage of the Polaris; kindly loaned by Dr. Emil Bessels. Figs. 3-6 drawn and filled in with the camera lucida by the author. Thos Sinclan & Sen. Lith Wciere } é W ry Na/intie : 4) bd lel 534 Fig. 7. Auth 7 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE X. BRANCHINECTA PALUDOSA and B. COLORADENSIS. . Branchinecta paludosa Mill. (arctica Verrill.), first foot of male. . Branchinecta paludosa Miill. (arctica Verrill.), second foot of male. Branchinecta paludosa Miill. (arctica Verrill.), tenth foot of male. . Branchinecta paludosa Miill. (arctica Verrill.), eleventh foot of male. . Branchinecta paludosa Miill. (arctica Verrill.), cercopoda. . Branchinecta coloradensis Packard, first foot of male. Branchinecta coloradensis Packard, eleventh foot of male. or, del. 536 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XI. BRANCHINECTA LINDAHLI and BRANCHIPUS VERNALIS Verrill, and details. Fig. 1. Branchinecta lindahli, 10th foot, x 14 B. Fic. 2. Branchipus vernalis Verrill. Enlarged 3} times; fg, frontal process; int, intes- tine; p, penis (gonopoda). Fie. 3. Branchipus vernalis, first foot of male, « 30 diameters. Fic. 4. Branchipus vernalis, first foot of female, x 30 diameters. Fia. 5. Branchipus vernalis, eleventh or last foot, male, X 30 diameters. Fic. 6. Branchipus vernalis, end of body (cereopoda) of male. Fig. 7. Branchinecta lindahli, end of body of female, x 30 diameters. Fig. 2 drawn by Mr. E. Burgess ; the other figure by the author, with the camera lucida. Ss. Geolog “Plate XT hi Ze WANN \ \\ ww \ \ — ft nl \ ical Survey. Thos. Sinclair’& Son, lath FE .Burgess and A.S. Packard, del. 538 Fig. GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XI. STREPTOCEPHALUS TEXANUS Packard, details. . First foot, male from Kansas, x 4 A. . First foot, male from Texas, < 50 diameters. . Sixth endite of 2d foot, from Texas, x 50. . Sixth endite of 9th foot, from Texas, x 50. . Tenth foot of specimen from Kansas, xX 50. . Eleventh foot of specimen from Kansas, x 50. . End of body of specimen from Kansas, x 30. Drawn by the author, with the aid of the camera lucida. % : N ‘ VRa i) ra y: 2 Aig y Daye A.S Packard del. UM, 540 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XIII. CHIROCEPHALUS HOLMANI Ryder, details. Fic, 1. Foot of the first pair, with the folléwing one, from a female; the 1st slightly overlapping the 2d foot, x $A. liq. 2. Tenth foot of a female; the sixth endite is turned down and the fifth turned up, X +A., the third and fourth endites not seen. Fia. 3. Third foot, showing the third and fourth endites, between the Ist and 2d, and the 5th, only the latter designated by the sign J5. Fig. 3a. Sixth endite from the third foot. Fig. 4. Frontal process of an old, large male. Fig. 5. Frontal process of younger, smaller male. Drawn by the author, with the aid of the camera lucida. Plate XII. a. “un Ss. Geological Survey. ; err ; ( WS'Paelkard, del. a Thos Sincleir:® Son, Lith a ae ; ae 542 Fia. 1. Fia. 2. FG. 3. Fie. 4. Fie. 5. Fia. 6. FIG. 7. GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XIV. THAMNOCKEPHALUS PLATYURUS Packard, details. An anterior leg. A middle leg. A posterior leg. Section through the body, showing the relation of the heart, intestine (in), and nervous cord (n g, a pair of nervous ganglia cut through) to the body walls and the appendages, /5, 16, the two last pair of endites, br, the gill. The male frontal appendage; 5a, end of a branch showing the twigs, and the wrinkles and spinules with which the appendage is armed. The female frontal appendage. Side view of the head of the female without the frontal appendage, at, first antenna ; at!, claspers or 2d autennz ; eye,—the eye and eye stalk. Plate XIV di ALS Packard, del. Thos Sinclair-& Son, lath a bt oh Gntead Rae ee pe yeaa 544 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XV. Fic. 1. Apus equalis Packard, 9 enlarged twice. la, upper; 1b, undcr side of the tel- son enlarged. Fic. 2. Lepidurus couesii Packard, nat. size. 2a, side view of the same. Fig. 3. Lepidurus bilobatus Packard, nat. size. Drawn by J. H. Emerton. verton, del, Sepeevaed Fiche os . i = 7 a ; = oe | 4 3 4 Z 3 g i * i 24 4 i i 2 i i 5 f f = c- E 5 & | can musa Ccnra ECR Thos Sinclair & Son, lath RY: NE ate wi Mi biienlah 546 Fig. ¥iG. 5 ls 6) 2 wa > 3. 4 5. GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XVI. Lepidurus glacialis, enlarged nearly 3 times. la, upper, 1, under side of the telson enlarged. Apus lucasanus Packard, nat. size. 2a, upper; 20, under side of telson, en- larged. Apus “newberryi Packard, nat. size. 3a, upper; 3b (on right-hand side), under side of telson, enlarged. . Apus longicaudatus Le Conte, upper, 4a, under side of telson. Apus himalayanus Packard, telson, 5a, under side of telson, enlarged. Drawn by J. H. Emerton. Asie ee eae JH. Emerton, del. Thos. Sinclaiz'% Son, Lith: neve + 548 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XVII. Fie. 1. Lepidurus glacialis, first foot; cl, gnathobase or coxal lobe; cl', the same of the succeeding limb. Fic. 2. Lepidurus couesii, first foot. Fig. 3. Lepidurus couesii, first foot of another (malformed?) individual. Fie. 4. Lepidurus bilobatus, 2, first foot. Fig. 5. Lepidurus glacialis 9 , second foot. Fig. 6. Lepidurus bilobatus, 9 , second foot. Fig. 7. Lepidurus couesii, second foot. All enlarged ; drawn by the author, with the aid of the camera lucida. =o =H. sac see FEAL \ os Sse NN =e z Aaa Sh SO aa Thos. Sincleir-& Son, ith: A.S.Packard, del. 550 Fia. Fic. Fic. Fig. Fig. Fig. Fic All th GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XVIII. 1. Apus equalis, 2, tenth foot. 2. Apus newberryi, 9, tenth foot, x, ‘‘subapical lobe.” 3. Apus lucasanus, tenth foot, x, asin Fig. 2. 4, 5 6 7 Apus longicaudatus, tenth foot. . Apus lucasanus, eleventh foot of the female, with the ovisac, containing a few eg gs. . Apus longicaudatus, eleventh foot of female. Apus newberryi, eleventh foot of female. e figures on this and Plates XIX-XXI much enlarged, and drawn by the author with the camera lucida. U.S. Geological Survey. Plate XVI ~--modified gill Newco {----modified jf i gil I-sac A.S. Packard, del. Thos: Sigplair-& Son, Lith dye scree Wy ; ie ica HEA BLE ee eH 5 i i , dulce on 552 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XIX. Apus lucasanus, first foot; cl, gnathobase; cl, that of the following appendage. . Apus equalis, second pair of feet. . Apus newberryi, 9, second pair of feet. . Apus longicaudatus, second pair of feet. . Apus lucasanus, f; second pair of feet; differs from the female in having the filaments on the gill. g hos Sinclair’® Son, Lith. 2 AN ! a ae poe NSH 4 Y \ 4 y eo reeranpaes tee” tes { 4 = ee \ \ card, del. 5 ah} A.S.P.: i res Pie: ON 554 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XX. Fig. 1. Apus newberryi, 9, first foot. Fig. 2. Apus equalis, 2, first foot. Fic. 3. Apus longicaudatus, 9 , first foot. Fig. 4. Apus longicaudatus, g , first foot. a ia S rs co = =) ch a Ss — Ye 1 4 hig Rm i a Ly je SS A. / | / | ‘ \ “7a \ : 52?) } jou san A SS Ny oe \ \ MS j SN Fe \ i He 4 | rat ore i et, : i Ss ee | 1 eo ee he Z! i S we f A i on, Lath: &S Thos: Sihclair A.S.Paekard, del. ese Tae ees omBA ye sajna roa a eet REPT AAS OS gt He eaeadl Ah ieelinibe avin 2 Ant ing i ee hie? dist RAE AOR UNM BARE (eT aah Fake ne fue ier eye eh or Heaths BIN KEES: 556 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXI, Tia. 1. Lepidurus glacialis, female; tenth appendage. Fig. 2. Lepidurus glacialis, female ; eleventh appendage, with ovisac. Vig. 3. Lepidurus bilobatus, female; tenth appendage. Fig. 4. Lepidurus couesti, male; tenth appendage. Fig. 5. Lepidurus couesti, female; tenth appendage. Fig. 6. Lepidurus couesti, female; eleventh appendage. Fie. 7. Apus lucasanus, maxilla. Fig. 8. Apus lucasanus, maxilla, seen from the inside. Fic. 9. Lepidurus couesti, maxilla. Fig. 10. Apus lucasanus, maxilla. Fig. 11. Lepidurus couesii, mandible. Fic. 12. Apus lucasanus, mandible. Iria, 13, Apus lucasanus, outside view of the same specimen as Fig. 8 represents. ay sy IN N =F, 1\ FS Fk. 8 A\ 5 SAQA oo . se \ H / x x \ \ te \ j } } ", . oe Coes ~S = Q Ne / Js \ } (ESN j ges a } J i [Fig : Nava anit AM I! 7 t Thos. Sinclair’& Son, Lith: 558 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXII. ANATOMY OF ARTEMIA AND BRANCHIPUS VERNALIS. Fig. 1. Nauplius or first larval state of Artemia gracilis from Great Salt Lake. I, first antenn; II, second antenne, III, mandibles. Fig. 2. Artemia gracilis, from New Haven, ovisac and ovary; c, ovary; d@, anterior points of attachment of the ovary, the intestine passing between them}; e, e, ovi- ducts. Fic. 2a. Artemia gracilis, from New Haven, cells of the cement-gland. Fig. 2b. The same; end of the long middle lobe, with the cement-gland cells (ec) and the fully developed eggs (egg). Fig. 3. Branchipus vernalis. Male generative organs; f¢, testis; ¢’, first dilated portion of the testis; t’’, contracted portion or vas deferens; t'’’, second dilated por- tion, performing the function of seminal vesicle; dt, ductus ejaculatorius ; g, glandular and accessory apparatus; c, cirrus; br, gillof last left foot; int, intestine; ht, heart or dorsal vessel; hh, ostium, or valvular opening of heart. Fic. 4. Branchipus vernalis, pale variety, ovisac; a, external wall of the ovisac; 5, in- t ernal wall of the same; c, the two ovarian tubes (somewhat twisted and stretched in living specimens); d, anterior continuation of the_same; e, the two muscular oviduets; f, lateral portion of the cement-gland; g, median ) portion of the same; h, female valvular orifice ; ab?, third abdominal segment, Fia. 4a. Ovaries (ovt) and oviducts (ov) of pale variety. Fic. 4b. Side view of a contracted oviduct. Fig. 4c. Branchipus vernalis, oviduct filled with eggs, of an old red female; a, valvule, below which is the orifice ; c, transverse ridge; d, lateral protuberances ; e, margin of the following segment. Fig. 5. Branchipus vernalis, frontal process of a red male, the right side being the outer O1 a. Bae 8 2 edge, with double-headed papille. ne side of same in a pale male. , t, different forms of ocelli or median eye in pale races, ¢ and 9. , 2a, 2b, drawn by the author; the others by C. F. Gissler, Ph. D. ie ye Plate XXTL. ar & Son Lith. T. Sincl. A.S. Packard and C.F Gissler, del. j sa, : Sas we feet ay) oat) preyed fae cok, bah veer 560 FIG. FIG. Fig. FIG. FIG. FIG. GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXIII. ARTEMIA GRACILIS Verrill (from New Haven), details. . Artemia gracilis Verrill. Head, showing the rela#on of the brain to the eyes, optic nerves, and ocellus (ocel), with the stomach and liver; md, mandible; gl, rudimentary shell-gland. . Front of the body, showing the circulation of the blood; hf, heart; the dots and arrows indicate the course of the blood-currents; int, intestine. . End of the same individual represented by Fig. 2; ht, end of the heart, with the two valves (seen at Fig, 3a); vec, rectum; m, three pairs of muscular bands which hold the rectum in place. . Portion of the heart during action; the arrows on each side point towards the ostia or valvular openings; the blood discs are represented within the heart itself; ep.c¢, epithelial cells in the walls of the heart; m, muscles which hold the heart in place. . End of the body; rec, rectum; m, muscles; anus, vent. . One of the compound eyes; cone, one of the crystalline cones; retina, the black retina; op. n, the optic nervules; opn, the main optic nerve; r. m, retractor muscle of the eye ; g. op, ganglion opticum, consisting of gang- lionic cells, x $B. Fig. 7. Circulation of the blood in a foot, the dots representing the blood discs; the arrows indicating the course of the blood. Drawn from the living specimens, with the camera lucida. by the author. “Plate XX AS Poekard del. id: naa) Le Soa ae 562 ces GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXIV. . 1. Estheria belfragei, edge of carapace, greatly enlarged, Xx } Tolles, A. ocular . 2. Estheria jonesii, edge of shell, with a portion chipped off, x 4 A. . 3. Estheria mexicana, Ohio, x $A. . 4. Estheria dawsoni (fossil). Drawn by L. Trouvelot. . 4a. Estheria dawsoni, showing the granulated ridges, x 4 A. . 4b. Estheria dawsoni, showing the pits between the ridges. . 5. Estheria californica, x4 A. . 6. Estheria mexicana, Kansas, x 4 A. . 7. Estheria morsei, lowa; edge of the shell. FIG. Fig. 8. Estheria compleximanus, Kansas; edge of shell, x 225 diameter, 9. Hstheria mexicana, section through the entire animal, through the front part of thorax; ant!, antennx; ani?, base of second antennz ; shg, section through the shell-gland; br’, upper, br’’, lower division of the flabellum ; int, intes- tine; ng, nerve-ganglion ; 1-6, first to sixth endites. 10. Estheria compleximanus. Section through the posterior part of the thorax, the shell having been removed; lettering asin Fig. 9; mus, dorsal mus- cles. All the figures, except Fig. 4 drawn by the author. al Survey. o1c Ss, Geolo U clair & Son, lith. Phila. Sim ae A.S,Paclzard, del. 564 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXV. ESTHERIA MEXICANA AND E,. COMPLEXIMANUS, details. Fig. 1. Estheria mexicana. Second antenna. Fia. 2. Leg of first pair; male; cl, Ist endite. Fic. 2a. Hand, including the fourth endite with the palpiform thumb (p), and comb- like edge of the endite. Fig. 3. Leg of second pair, male. Fic. 3a. Hand of second pair of male, leg; musc, muscles of hand. Fig. 3b. Comb, or spiney edge of the fourth endite. Fic. 3c. Palpus-like terminal joint of the fifth endite, showing the sense-cells with which it is filled, and the tactile hairs at the extremity, x $ A Tolles. Fic. 4. View of the head with the double-eye, from above. Fia. 4a. The same, seen from the side. Fic. 4b. Another lateral view of the head and rostrum. Fic. 5. End of the abdomen, including the telson of the male (female the same). Fia. 6. Estheria compleximanus Packard. End of abdomen. Drawn, and details filled in with the camera lucida, by the author. us ilar Sr a one Serra ~N 4 "7 Ss wae at ie WOT MA ey vain AANA AES y ire LF Se peer enne ‘| T Sinclair & Sonimh) A.S:Paelcard, del. - Sy Rea hey SU Hye if 566 GEOLOGICAL SURVEY OF THE TERRITOLIES, EXPLANATION OF PLATE XXVI. . 1. Estheria morsei Pack; male, much enlarged. . 2. Estheria morsei; male, first foot. . 3. Eulimnadia texana Pack.; end of first’ antennz, showing the olfactory papills, and crowded nerve sense-cells. . 4. Limnetis gouldit Baird; end of first antennsw, showing the nerve-endings, the large nerve-cells, and the long, finger-like olfactory papille, x } A 3. 4a. Portion of end of the same, x + B ocular, showing the nuclei in the papille and the series of nucleated sense-cells. (The line on the right side was drawn by mistake; it should form the left side of Fig. 4.) . 5. Limnetis brevifrons Pack. ; first antenna. . 5a. End of the same (Fig. 5), much enlarged. . 6. Limnetis gouldit ; portion of the ovary, x $A. . 1 was drawn by Mr. E. Burgess; the other figures by the author. Plate XXV1 U. S. Geolocical Survey. T Sinclair & Son, Lith. Pina “Packard. del ess and \ E Burd A OTE URC Aton CUB estes xf Me i eed iat E a aK nei 568 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXVII. Fic. 1. Limnetis brevifrons Packard ; second antenna of female. Vig. 2. Limnetis brevifrons Packard ; first leg of female. Fig. 2a. Limnetis brevifrons Packard; end of first leg of Fig. 2, showing endites 4-6 and the lower division of flabellum (br’’), Fig. 3. Limnetis brevifrons Packard; male, first leg (en? above en® should be en), All the figures drawn by the author. Plate XXVIT TD. Sinclar & Son, lith, Phil A.S' Packard, and E-Purgess del. US. Geological Survey: 570 GEOLOGICAL SURVEY OF THE TERRITORIES EXPLANATION OF PLATE XXVIII. Figs. 1-5. Hstheria mexicana Claus,oimmature specimens from Kentucky (2. elarkié Pack.). Fig. 1. Thoracic leg, female. Fig. 2. Fifth leg from the last. Fig. 3. First antenna. Fic. 4. Second antenna. Fig. 5. Telson. Fic. 6. Estheria jonesii Baird ; second antenna. U.S. Geological Survey: + Plate XX VII 1 ae eS a ae A.S.Paelard, del. = ia ee aaaaieg : T Sinclair & Son, Lith. Phila. He Nat = NSE: eee ua ai a Aa 572 Fia. FG. Fic. Fig. Fig. FIG. FIG. Fic, Fig. Fia. Fic. FIG. Nig. GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXIX. 1. Hstheria mexicana Claus, from Kansas (2£. caldwelli); first antenna; 0/, olfac- tory lobes; at, n, antennal nerve. la. Terminal joints of the same, filled with olfactory cells; no papillae present. 1b. Olfactory lobes from near the middle of the antenna. 2. Estheria mexicana (caldwelli); three terminal joints of the second antenns, showing the nerve-endings and the sense-cells at the base of the sete. 3. Estheria compleximanus, edge of sixth endite (of Pl. V, fig. 7), showing the ends of the tactile nerves leading to base of tactile sete and connecting with the marginal nerve; with the two series of independent nerve or ganglion cells, X 225 diameters. 4, Estheria compleximanus Pack.; end of the dorsal lobe or oviger of one of the anterior legs (figured on Pi. V, fig. 7), showing the tactile nerve (tr) with its ganglionic enlargement near and at the end of the lobe ; with the gan- glion cells at the base of the sete. 5. Estheria compleximanus, end of 5th endite of Ist leg (Pl. V, liz. 5), showing the very large crowded ganglionic tactile cells (ge). 6. Branchipus vernalis Verrill. End of 1st antenna, with the three tactile setx at the tip; », antennal nerve; gc, ganglion cells, x $A. 7. Thamnocephalus platyurus Pack. The 3d or 4th endite of the 1st foot, with n the nerve to the endite, the large ganglion cells arranged in quite regular series, and én the origin of a tactile nerve passing into the seta(s); each seta is about to moult, as the new set# with the fine setule are present. 8. Thamnocephalus platyurus Pack. Portion of the edge of Ist or innermost endite of 1st pair of feet; n, nerve-fibres; gc, ganglion cells; tn, tactile nerves pass- ing into the long, slender set (8), near tn, the marginal row of fine seta. 8a. Thamnocepholus plat yurus Pack. Cuticle of flabellum with nuclei (n) and fine tubercles. 8b. Thamnocephalus platyurus Pack. Cells at base of 5th endite containing fat granules. 9. Limnetis gouldii. One eye with the cornea removed, the same specimen as repre- sented on Pl. II, fig. 5. Op.n, optic nerve; the upper op. n. should be op. g, optic ganglion. From the peripheral nucleolated cells the nerves with the rods (if the latter are present) converge towards the optic ganglion; tr. n, transverse nerves arising from peripheral cells and connecting the two eyes. All the figures drawn with the camera lucida by the author. & Son Lith. aiz TSmck Cire S, Packard, del. sien Pie 574 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXX. Fig. 1. Branchipus vernalis Verrill. Sixth endite of an anterior leg, showing the mus- cles and tactile nerves, which arise independently of the central nervous system near the margin of the lobe; nc!, inner series; nc*, marginal series of ganglion cells; on the left side the origin of the setal nerves are seen. Fig. 2. Streptocephalus tecanus Pack. The 6th endite of an anterior foot. Fig. 3. Streptocephalus texanus Pack. et ereaore. ian’, ine ESS RUT Toiatet tesa ecartctatne-ariyannprseuvesitegvararecer nero site a , APPT, pe gaptararet 5: st) & f N= J eae a at ar U.S. Geological Survey. yy _ Grube Packard, det King sle T. Sinclair & Son Lith. ANATOMY OF APUS. wi 4 aM u i 578 GEOLOGICAL SURVEY OF THE TERRITORIES, EXPLANATION OF PLATE XXXII. Fig. 1. Apus lucasanus Pack. Section through the body, with the intestine removed md, mandible; ani!, ant?, Ist and 2d antenne; leg, first pair of legs; br. flabellum ; ov, ovary; ng, ganglionic chain. . 2. Transverse section through the body at the 7th or 8th pair of feet, the shell removed, mus, dorso-ventral adductors of the feet, crossed by the ad- ductors of the exites; hi, heart; int, intestine; ov, ovary; 2. g, ventral ganglion; en!—en®, endites; br, gill; jl, flabellum; x, subapical lobe. Fig. 2a, 1st antenna; 2b, 2d antenna; 2c, the extremity of 2d antenna, with 4 bead- like joints, showing the three imperfect joints, the third ending in a monili- form portion. Fic. 3. Maxillipede with the gill (br) and single endite. Fia. 4, 4a, dorsal and lateral view of the brain of the European Apus canecriformis; br, brain; com, commissure to subcesophageal ganglion; g op, optic ganglion; oc, ocellus; oes, end of esophagus. Fig. 5. Brain and part of ventral cord of Apus cancriformis; oc, nerve #o ocelli; ant’, ant, first and second antennal nerves; G!, esophageal; G*?, mandibular ganglion, sending off three mandibular nerves (n md); d, descending @so- phageal nerve; h, unpaired or lower cesophageal ganglion; oes, nerve pass- ing to the muscles of the esophagus. Fic. 6. Heart of Apus cancriformis. Fic. 7. Apus longicaudatus, portion of embryonic membrane lying next to the chorion, and supposed to represent the amnion in Limulus; the nuclei in many of the cells have become absorbed. Fig. 8. An egg of the same, showing the cellular nature of the amnion. Fic. 8a. A portion of the same amnion seen sideways of the egg. Fig. 1 drawn under the author’s direction by J. 8. Kingsley; Figs. 4, 4a, 5, and 6, copied from Zaddach; the remainder drawn with the camera by the author. Fr Q Kingsley Zaddach Packard, del. ANATOMY OF APUS. Plate XXXII. hy T. Sinclar & Son fith. be a i yaks is t) Ay ‘ a : 580 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXXIII. Fic. 1. Estheria mexicana Claus (Caldwelli, from Kansas). Section through the shell, hinge, and body; oes, esophagus; oc, larval eye or ocellus; add, m, adduc- tor muscle of the valves; md, mandibles; ov, ovary; gl, liver Fig. 2. The same, section through the stomach, showing the biliary ducts leading into the stomach from the convoluted liver lobules; br, brain. Fic. 2a. Section through a biliary tube. Fig. 3. Eye of HZ. mexicana; ¢, cones; 7, rods. Fic. 4. Oblique section through head of £. mexicana; c, cones; ret, retina. Fig. 4a. Section of the esophagus in Fig. 4, enlarged. Fig. 5. Section through ganglia (gang) near but posterior to the maxillw, and through the intestine (int). Fic. 6. EL. mexicana, ovary; ep, epithelium. Fic. 7. E. mexicana, section through the shell and hypodermis; sh, shell; lc, large : secreting cells; f, fibers. Fic. 8. Branchipus vernalis Verr. Section through the brain and eye,X4A; 8a, & por- tion from the middle of the brain, x A. Fig. 9. Branchipus vernalis Verr. Section through the eye; ¢, cones; ret, retina; ret, second retinal streak; r, rods; g. opt, optic ganglion; n. op, optic nerve. Drawn by the author from sections made by Mr. N. N. Mason. Plate XXXHE, Dy U.S. Geological Survey. stomach Sinclar & Son Lith. T. AS. Packard, del. 582 GEOLOGICAL SURVEY OF THE TERRITORIES EXPLANATION OF PLATE XXXIV. Fia. 1. Streptocephalus texanus Pack. Third developmental stage, dorsal view. Length Fia. Fic. Fig. Fig. rig. Fig. Fig. Fig. Fig. Fig. Fig. 0.2™™, oc, ocellus; md, mandibles; mdp, mandibular palpus; sg, shell gland; M, transverse muscle of the 2d antenne ; m, levator muscle of the labrum} m2, rectal muscles; int, intestines; s!, forked spine on 2d joint of 2d anten- ne. la. Union of the two muscles m! in Fig. 1. 2. 2d antennsz seen from below. Larva 4.2™™ in length. . Ist antenna, 3d larval stage; n, antennal nerve; mnc, marginal nervye- cella? sp. ¢, bipolar spindle- shaped cells; s, sete. . Ist antenne of larva when 3™™ in length; lettering as in Fig. 3; gc, terminal ganglion cells. . 2d antenne of larva 4™ in length; s!, s?, spines of basal joints. . Mouthparts of same larva as Fig. 5, and drawn to the same proportions; md, mandible; mp, mandibular palpus; ; ma}, Ist maxilla; mp, Ist maxillary palpus; mit, 2d waxilla. . The maxille (ist and 2d) of larva when 5™™ in length. . Chirocephalus holmant Ryder (Glendale, L. I.), tip of Ist antenne and olfactory seta. . Mouth of larva of S. texanus when 5™™ in length. 10. Branchipus vernalis Verrill. Olfactory seta. 11. Chirocephalus holmani Ryder. Dorsal bristle of 3d segment, a little way from the articulation; Fig. 11a, the same on the 2d (genital) segment. Note.—All the figures in ‘this | plate were drawn by C. F. Gissler, Ph. D. Plate XXXIV _U.S. Geological Survey: carapace T Sinclair & Son, ith. Pra. C.F.Gissler, del. 584 GEOLOGICAL SURVEY OF THE TERRITORIES. Fie. . 2. Ist antenna of larva 5™™ long, . 3. 2d antenna of Hulimnadia texana Pack. . 4. Mandible (left) of Apus lucasanus Pack. . 4a. Mandibular palpus of Hulimnadia texana Pack. - 4b. The last smallest tooth on the cutting edge of the mandible, enlarged. . 5. Apus lucasanus; 1st maxilla of larva 5™™ in length, with the maxillary lobes EXPLANATION OF PLATE XXXV. 1. Apus lucasanus Pack., raised from mud from Kansas. Larva about 7™™ long. and the spinose portion. . 6. 2d maxilla of Fig. 5, drawn to the same scale. . 7. Apus lucasanus ; Ist leg of male larva when 5™™ in length. en!—en’, endites 1-6. ax—axt, pseudo-joints of the axis of the limb; en!, the gnathobase. . 8. Apus lucasanus; End of abdomen of larva 3-5™™ ea . 9. Apus lucasanus; End of abdomen of larva 1™™ in length. rec, rectum; m, sphincter muscles of anus; cr, chitinous rod. - 10. Apus lucasanus; Lower margin of shield of g 5™™ in length; -lat, lateral line becoming gradually obliterated; tp, inner posterior line. Nete.—All the figures on this plate were drawn by C. F. Gissler, Ph. D. Uv. S. Geological Survey: Ss a ee cepa a I Lite p tt ~ " | Behl es aS f / — RNa YON aS : x ee ee 12 i oy f NCeUGG iS / : . a ‘ ACC Naeriat es RAIL aT TT Ny th we ee oe ee C.F.Gissler, del, T Sinclair & Son, ith. Phila. 586 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXXVI. Fig. 1, Nebalia bipes Kroyer; female, much enlarged. Fic. 2. Nebaha bipes Kroyer; female, head; ros, rostrum; car, carapace; ant’, Ist an- tenna, (1-5) five basal joints; ex, exopodite; ed, endopodite; ant?, 2d antenna, with 1-3, three basal joints; pes!, part of first pair of feet; md, mandible; mx, first maxilla; mx, second maxilla; st, stomach. Fig. 3. The carapace flattened out to show relations of rostrum. Fig. 4. Mandible, md, cutting edge; p, palpus. Fic. 5. The two maxille; 1-4, the four lobes of the coxopodite. HIG. 5a. Ist maxilla; cx!, cx?, coxopodite; en, endopodite. Fig. 6. (Omitted.) Fie. 7. Cercopoda or caudal stylets. Fic. 8. Portion of dentate edge of an abdominal segment. Fie. 9. Section through a ventral ganglion. Author del. Plate XXXVI U.S. Geological Survey: oe of LLAMAL | fe ‘ [Sinclair & Son, Lith. ' A,S. Packard, del ANATOMY OF NEBALIA PIPES. Eh On ies 588 maces Fig. Ei. ; FIG. Fig. Fie. ices GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXXVILI. . Nebalia bipes Kr. 9; Ist antenna; lettering as in Pl. 36; k, lobe from 4th joint. . 2d antenna. . One of the 3d or 4th pair of thoracic feet; fl, flabellum; ex, exopodite; om, endopodite. . One of 2d pair of abdominal legs; ret, retinaculum; en, endopodite; ex, exop- odite. . One of the fifth pair of abdominal feet. . Section through the body just behind the first pair of thoracic feet, through the stomach (st), and the two anterior coca (ote); add. mus, adductor muscle; sh, shell. . Section through one of the coca. Plate XXXVII T Sinclair * Son, Lith. ee ANATOMY OF NEBALIA PIPES is at ana, D8 590 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXXVIUII. Lettering. aw, first pair of antenne. a*, second pair of antenne. md, mandibles. mx}, first pair of maxille. mx, second pair of maxille. po’, first pair of thoracic feet. po", second pair of thoracic feet. th. l, thoracic feet. ab. f, abdominal feet. @, esophagus. ep, epithelium of stomach. p. d, procephalic or antennal lobe. st, stomach. Fic. 1. Embryo of Nebalia geoffroyi in the Nauplius stage. Fig. 2. The same, farther advanced, with the rudiments of the cephalic and first two thoracic appendages and the hind gut. Fic. 8. The same, still more advanced, the biramous thoracic feet developed. Fre. 4. Embryo of the same nearly ready to hatch. Fig. 5. Embryo at the time of hatching. Figs. 1-5 copied from Metschnikoff. Fig. 6. Embryo of Schizopod Pseudomma roseum. Copied from Sars. U.S. Geological Survey of Territories. Pl. XXXVIILI. Fig. 4. DEVELOPMENT OF NEBALIA. 592 GEOLOGICAL SURVEY OF THE TERRITORIES. EXPLANATION OF PLATE XXXIX. Fia. 1. End of postabdomen with the furca of Artemia salina taken from the Kujal- niker salt lake in spring, 1871, at 8° Beaumé, after an inundation. Fig. 2. The same part of an Artemia salina taken in summer, 1872, at 14° Beaumé, from the Kujalniker salt lake. Figs. 3 and 4. The same parts of the already more changed Art. salina, taken from the same lake in summer, 1873, at 18° concentration. Fic. 5. The same part of an Artemia forming a transition between Art. salina and Art. milhausenti. ‘Taken from the same lake in the first half of August, 1874, at 234° concentration. Fig. 6. End of the postabdomen of an Artemia which I take for Art. milhausenii. Taken from the same lake in beginning of September, 1874, at 25° concen- tration, when salt began to deposit itself. Fig. 7. One of the middle gills of Art. salina. Fig. 8. One of the middle gills of Art. milhausenii. Fig. 9. The lower part of the postabdomen of an Art. salina taken from the Hadschibei Lake at 10° concentration. a, end of the sixth segment; b, seventh segment; c, long eighth segment with the furcal lobes; d, bristles occurring at the end of each segment before the articulation (but two have been drawn of each ring); e, the - same bristles nearly in the middle of the eighth segment. Fig. 10. The lower part of the postabdomen of a young specimen of the third genera- - tion of Art. salina, which was domesticated in gradually diluted salt water for the purpose of yielding progressive growth. a, end of the sixth segment; b, seventh segment; ¢, eighth segment; d, ninth segment; e, two of the bristles from the bristle-ring occurring at the end of each segment before the articulation; f, spot where the long eighth segment divided into two segments, the eighth and ninth. Fig. 11. A group of cuticular cells found near the base of the above-mentioned bristles of the postabdomen of Art. salina, whose lower part is illustrated by Fig. 9. Fig. 12. A group of denticular spines found near the base of the bristles of the post abdomen of progressively changed individuals of Art. salina, whose lower part of the postabdomen is illustrated by Fig. 10. Figs. 1 to 10 are 65 times, 11 and 12 are 330 times magnified. Copied from Schman- kewitch. . U.S. Geological Survey. Pl. XXXIX. G a 35 : ae b 28 | f | TRANSFORMATION OF ARTEMIA INTO BRANCHIPUS. RO 6 en fave sy hte a Ona a vk = Vay ten fh ea i ent eT eat) Hee ale ‘i Lay Sine! IN) TE OX Allen, J. A., 69 Alpestris, osteology of, Eremophila, 627 Apodide, 315 Apus, 319 cequalis, 320 domingensis, 326 dukianus, 327 guildingii, 326 himalayanus, 327 longicandatus, 324 lucasanus, 322 newberryi, 321 Apus cancriformis, nauplius of, 416 Apus lucasanus, eggs of, 426 larval stages of, 428 Argus, 444 Artemia, 329 fertilis, 330 gracilis, 330 guildingii, 334 monica, 330 utahensis, 330 Artemia fertilis, parthenogenesis in, 459 Artemia salina, parthenogenesis in, 461, 462, 463 Artemia arietina, 466, 501 muelhausenii, 466 Artemia salina, relation of, to A. Milhau- senii and to Branchipus, 466 Artemia, character of, 509,513 Artemia koeppeniana, 506 Artemia, influence of change of external conditions on, 473, 491, 501 Bowditch, F. C., 271 Branchinecta, 334 coloradensis, 335, 338 lindahli, 339 paludosa, 336 Branchipodide, 328 By cuipodiae, reproductive habits of, 42 Branchipodine, 328 Branchipus, 340 arietinus, 466 characters of, 509, 514 ferox, influence of change of conditions on, 474 spinosus, 487 grubei, 496 serratus, 343 stagnalis, nauplius of, 416 vernalis, 343, 420 larval stages of, 428 Broadhead, G. C., 155 Brine shrimp, 330, 459 Carboniferous fossils, 119, 155 | Carthartide, osteology of the, 727 pelvis and lower extremity of the, 776 pneumaticity of the skeleton of the, 736 pygostyles of the, 761 scapular arch, sternum, and pectoral limb of the, 765 skull of the, 740 species representing the, 729 table of cranial differences among the, 753 table of external characters of the, 732 vertebral column of the, 754 vertebral ribs of the, 762 Ceratiocaride, 499 Ceratiocaris, 444, 450 Chirocepbalus, 351 holmani, 351 Chirocepbalus holmani, larval stages of, 424 Chlamidomonas dunalii, 489 Cladocera, limbs of, 404 Clark, Frederick C., 173 Conditions, external, influence of, on Phyl- lopod crustacea, 473 Cope, E. D., 69 Cretaceous fossils, 5 | Crustacea, classification of, 446, 448 eyes, 414 genealogy of, 416, 418 limbs of, 414 morphology of legs of, 387, 404 Crustacea, Phyllopod, 295 fossil, 355 geographical distri- bution of, 362 Crustacea, Phylloped, eyes of, 3-0 morphology and an- atomy of, 370 | Cyclops bicaudatus, 479 Cyclops bicuspidatus, 499 odessanus, 499 Cyzicus, 303 Dall, W. H., 10 | Daphnia, degenerata, 478 magna, 478, 479 pulex, 478 Daphnia rectirostris, influence of change of conditions on, 475 Decapoda, limbs of, 405 Dictyocaris, 444, 451 Dithyrocaris, 444, 451 | Dorsal vertebre, sternum, Eremophila,637 | Kehinocaris, 450 (807) 808 Endlich, F. M., 134 Kremophila alpestris, 627 Estheria, 303 Kstheria belfragei, 309 californica, 304 caldwelli, 306 clarkii, 306 compleximanus, 305 dawsoni, 358 dunkeri, 306 jonesii, 310 mexicana, 306, 354 morsei, 308 newcombii, 305 oyata, 356 watsoni, 354 Estheria compleximanus, larval stages of 426 Eubranchipus, 340, 342 Eulimnadia, 311 agassizli, 311 antillarum, 314 stanleyana, 311 texana, 312 Evolution in Artemia and Branchipus, 466 Geographical distribution of Phyllopods, 362 Gilbert, G. K., 119, 136 i Gissler, C. F., on reproductive habits of Branchipodide, 420 translation by, 459, 463, 466, 473 Gros Ventre Range, 208 Gros Ventre Basin, 219 Gurley, W., 155 Hayden, F. V.: Letter of transmittal, xvii Hedessa, 298 Hoback River, 180, 202 Holmes, W. H., 60, 151 Hyatt, A., 283 Hymenocaris, 444, 449 Hyoid arch, Eremophila, 634 Hyoid arch, Lanius, 720 Tsaura, 303 John Day Ridge, i387 Jurassic fossils, 143 Lakes, Arthur, 5, 271 Lanius, 719 Laramie group fossils, 49 Leaia, 356 leidyi, 358 Lepidurus, 315 angusii, 319 bilobatus, 316, 318 couesii, 316, 317 glacialis, 316 viridis, 319 Lepidurus productus, nauplius of, 416 Lesquereaux. Leo, 174 Limnadella Kitei, 313 Limnadia, 311 americana, 311 coriacea, 313 Limnadia hermanni, naupliius of, 415 Limnadiad, 297 Limnetine, 298 Limnetis, 298 brevifrons, 301 INDEX. Limnetis gouldii, 299 gracilicornis, 302 mucronatus, 300 Limulus, affinities of, 411 limbs of, 407 Lobster, limbs of, 405 Lower mandible, Eremophila, 634 Ludovicianus, osteology of, 719 Marnoch, G. W.,6 Monas dunalii, 489 Morphology of Phyllopod crustacea, 370 Moulting in Phyllopod crustacea, 377 Mushbach, J. E., 114 Nebalia, 444, 449 Nebalia, anatomy and development of, 433, 440 Nebalia, palwozoic allies of, 443 limbs of, 407 Nebaliade, 445 Nicholson, H. A., 6 Osteology of the Cathartidz, 727 Eremophila alpestris, 627 Lanius ludovicianus ex- cubitorides, 719 North American Tetra- onide, 653 Speotyto cunicularia hypogea, 593 Packard, A.S., jr., 149 Packard, Prof. A.S., jr., on Phyllopoda, 295 on the order of Phyllocarida, 432 report of, 294 Paleontology, contributions to: No. 2, by C. A. White. No. 3, by C. A. White. No. 4, by C. A. White. No. 5, by C. A. White. No. 6, by C. A. White. No.7, by C. A. White. No. 8, by C. A. White. Paranebalia, 449 Peale, A. C., 115, 174, 271 | Peltocaris, 444, 449 Pelvis and the pelvic limb, Lanius, 723 Pelvic limb, Eremophila, 648 Perry, Nelson, 173 Phyllocarida, character of, 447 limbs of, 407 order of, 432 Phyllopoda, 297 brain, 400 heart, 399 liver, 397 mouth, 397 nervous system, 400 ovaries, 398 stomach, 397 | Phyllopoda, crustacea, 294. fossil, 355. geographical distribution of, 362 geological succession of, 355 histology of, 361 Phyllopoda, development of, 415 encalogy of, 415 istology of, 370, 372 morphology and anatomy of, 370 ; moulting of, 377 INDEX. Phyllopoda, nomenclature of, 372 reproductive habits of, 420, 423 Powell, J. W., 153 Rachura, 451 Sacral vertebrae, pelvis, Eremophila, 640 Salt Lake brine shrimp, 330, 459 breeding habits of, 489 winter eggs of, 462 Scapular arch, Eremophila, 643 Scapular arch and pectoral Llimb, anius, 723 Schmankewitsch, W. J., on the influence of external conditiozs of life upon the organization of animals, 473 Schmankewitsch, W.J., onthe transfor- mation of Artemia into Branchipus, 446 Scudder, Samuel H.,Report of, 271 Tertiary Lake Basin at Florissant, Colo., 271 Shufeldt, R. W., osteology of Eremophila alpestris, 627 Shufeldt, R. W.: Osteology of Lanius ludovicianus ex- cubitorides, 719 Osteology of Speotyto cunicularia hy- pogea, 593 Osteology of the North traonide, 653 Osteology of the Cathartide, 727 Siebold, C. T.: On breeding habits and eggs of Arte- mia jertilis, 459 On parthenogenesis in Artemia sali- na, 463 Skull, Eremophila, 627 Skull, Lanius, 719 Speotyto cunicularia hypogea, osteology of, 593 dorsal vertebre, sternum, 604 hyoid arch, 599 lower mandible, 600 pelvic limb, 616 sacral vertebree, pelvis, 608 scapular arch, 611 spinal column, cervical portion, 601 upper extremity, 613 Spinal column, cer:ical portion, Eremo- phila, 635 Sternum, Lanius, 722 St. John, Orestes, report of, 173 St. John, O., 121, 144 Streptocephalus, 344, 348 floridanus, 350 similis, 350 texanus, 345 American Te- 809 Streptocephalus texanus, larval stages of, 426 Taste, organs of in Crustacea, 384 Tertiary fossils, 41 Tertiary Lake Basin, Colorado, by S. H. Scudder, 271 Tetraonide, ostenlgy of the North Ameri- can, 653 ofthe pelvis and pel- vic limb, 691 of the scapular arch and pectoral limb, 686 of the skulls, 661 of the sternum, 681 of the vertebral col- umn, 675 Thamnocephalus, 532 platyurus, 353 Triassic fossils, 105 Trilobites, limbs of, 408 Upper extremity, Eremophila, 545 Vertebral column, Lanius, 721 Wachsmuth, C., 155 Wadsworth, M. E., 276 Walker, D. H., 33 Western Territories, distribution of life in, 364 White, C. A., 174 Contributions to Paleontology, No. 2. Cretaceous fossils of the Western States and Territories,5 Contributions to Paleontology, No. 3. Tertiary mollusca from Colorado, Utah, and Wyoming, 41 Contributions to Paleontology, No. 4. Fossils of the Laramie group, 49 Contributions to Paleontology, No. 5. Trassic fossils trom South- eastern Idaho, 105 Contributions to Paleontology, No. 6. Carboniferous fossils from the Western States and Territories, 119 Contributions to Paleontology, No.7. Jurassic fossils from the Western Territories, 143 Contributions to Paleontology, No.8. Carboniferous fossils from the Interior States, 155 Whitfield, R. P., 37 Winchell, Professor A., 121 Wind River District, 175 Wind River Range, 228 Wind River Basin, 255 Wyoming Range, i78 Zoogeography, 362 Alias dia: jal a Vs Ei ta Fie OcTOBER 26, 1883.] SC IENCE. Ta | PACKARD’S PHYLLOPOD CRUSTACEA. A monograph of the phyllopod Crustacea of North America, with remarks on the order Phyllocarida. By A. S. Packxarp, Jun. Author’s edition, extracted from the twelfth annual report of the U. S. geological and geographical survey. Washington, 1853. 298 p., 89 pl., map. 8°. AxrHouGcH Professor Packard began publish- ing upon the Phyllopoda long ago, and has for several years been well known to be engaged upon a monograph of the North-American spe- cies, the bulk of the work just published, and the profusion of its illustrations, are a great surprise. It is the most extensive, and in many ways the most important, monographic contribution to American carcinology ; and, however we may criticise the execution of the work, every student of the American fauna must feel grateful to the author for undertak- ing and accomplishing it. The work is much more than a systematic monograph of North-American Phyllopoda, as the following table of contents will show: I. Classification of the living Phyllopoda, which includes the systematic description of the North-American species; IL. Geological succession, including descriptions of the North- American fossil species; III. Geographical distribution; IV. Morphology and anatomy ; V. Development, metamorphoses, and gene- alogy; VI. Miscellaneous notes on the repro- ductive habits of Branchipodidae, by Carl F. Gissler; VII. The order Phyllocarida, and its systematic position; VIII. Bibliography ; Ap- pendix, consisting of translations or abstracts by Gissler, of papers by C. T. von Siebold, on Artemia fertilis from Great Salt Lake, and on parthenogenesis in Artemia salina; and by Schmankewitsch, on the relation of Artemia salina to Artemia Muehlhausenii and to the genus Branchipus, and on the influence of ex- ternal conditions of life upon the organization of animals. There is some confusion between the titles of the principal divisions, which are given above, and the table of contents in the work itself. Scarcely any of the titles are the same; and, in place of ‘ Miscellaneous notes on the reproductive habits of Branchipodidae,’ we have, in the table of contents, ‘ Relation to their environment; habits,’ — subjects no- | where treated under a separate heading ; and — all reference to the long appendix is omitted. | About a fourth of the entire work is devoted | to the systematic account of the species and higher groups of Phyllopoda, regarded by Pro- fessor Packard as a sub-order of Branchiopoda, which is made to include Cladocera and Ostra- coda also. The Phyllopoda are divided as follows into families and sub-families, which include the number of recognized North- American genera and species nearly as indi- cated : — LIMNADIIDAE : Limnetinae (1 genus, 4 species). Kstheriinae (3 genera, 11 species). ApopIDAk (2 genera, 9 species). BRANCHIPODIDAE : Branchipodinae (5 genera, 12 species). Thamnocephalinae (1 genus, 1 species). All the groups are described; nearly all the species are figured, many of them very fully ; and important notes on variability and habits are given for some of the species. Artemia gracilis is treated more at length than any other species, and is made to include all the described North-American species ; but, in re- gard to its relation to the European A. salina, there is certainly confusion, as the following paragraphs show. ‘* Upon comparing our species with the Eu- ropean, it is difficult to find good differential characters, as the portions of the body where specific differences would be expected to occur are liable to considerable variation. Upon comparing a number of females from Great Salt Lake with a number of females of the maleless generation from ‘Trieste, Austria, received from Professor Siebold, there are really no differences of importance. Our A. gracilis (Verrill’s fertilis) is slighter, with a smaller head ; and perhaps the second antennae are a little slighter in build; I see no essen- tial difference in the form of the ovisac, while the shape of the legs, especially the sixth en- dite, is essentially the same ’’ (p. 331). ‘¢On comparing a number of Salt Lake fe- males with individuals of the same sex of the European Artemia salina, our species was found to be undoubtedly specifically distinct ; the Utah specimens are slenderer, smaller, and slenderer and longer in proportion than in A. salina. The ovisacs were of the same propor- tion but slenderer, and the head is slighter and smaller in our American species ’’ (p. 353). Different conclusions on neighboring pages, in regard to the specific identity of closely allied forms, might be accounted for in a careless author ; but differences like these in statements of observation betray inexplicable careless- ness. In the chapter on geological succession, a table of the geological and geographical distri- bution of the known fossil species is given, and also a diagram indicating the geological his- tory of the orders of Crustacea, the sub-orders of Branchiopoda, and the families of Phyllo- poda. It is said that this diagram ‘‘ may also serve as a genealogical tree, showing the prob- able origin of the main divisions of the Crus- _tacea :’’ but the genealogical part of the diagram consists simply of dotted lines connecting the points of first appearance in geological history of the Branchipodidae, Apodidae, and Clado- cera, with the point of appearance of the Lim- nadiidae in the Silurian; the common stem from this point with the Ostracoda in the upper Laurentian; and the branchiopod stem thus formed, and continued to a hypothetical Pro- tonauplius in the lower Laurentian, with the points of appearance of the Malacostraca, Phyllocarida, and Cirripedia. On what con- ceivable theory of evolution this would repre- sent a possible, much less the probable, origin of the main divisions of the Crustacea. it is hard to imagine, and was probably not serious- ly considered by the author himself; for it is far less like a probable genealogical tree than the diagram on p. 448, illustrating the rela- tions of the Phyllocarida to other Crustacea. In the chapter on morphology and anatomy, Professor Packard discusses at length the mor- phology of the regions of the body and the | appendages of Arthropoda in general, and of the crustacean limb in particular, and gives some account of the anatomy of the phyllo- pods, but adds very little to our previous knowledge of the anatomy of the group. ‘The morphological discussion is an interesting con- tribution to the subject, and, with the numerous figures with which it is illustrated, will prove very useful, although most of the new nomen- clature proposed for the regions of the body and appendages is very objectionable. Pro- fessor Packard says, ‘‘ For the primary regions of the head (sie), the only scientific terms as yet in use are those proposed by Prof. J. O. Westwood, in Bate and Westwood’s History of British sessile-eyed Crustacea (vol. i. p. 3). These are cephalon for the head, pereion for the thorax, and pleon for the abdomen; while the thoracic feet are termed pereiopoda, and the abdominal legs pleopoda; the three terminal pairs being called uropoda. As the names applied to the thorax and abdomen have no especial morphological significance, the Greek mepawov, simply meaning ulterior, and zAecor, more, we would suggest that the head be termed the cephalosome, the cephalic segments, cephalomeres, and the cephalic appendages in general, protopoda, the term ‘ cephalopoda’ being otherwise in use. The thorax of insects and of most Crustacea might be designated the baenosome (Bao, to walk, locomotion), and the thoracic appendages, baenopoda, the seg- ments being called baenomeres ; while urosome might be applied to the abdomen, the abdomi- nal segments being called wromeres. West- wood’s term wropoda might be extended so as to include all the abdominal appendages.’’ If mere. names of parts are to be rejected, simply for want of ‘morphological significance,’ the language of the morphologist would soon be- come a meaningless jargon, to which it is near enough already ; but, even as to‘ morphological significance,’ there appears to be little choice between the new and old terms. Bate, when first proposing the terms ‘ pereion’ and ‘ pleon,’ expressly states that he derives the terms from mepatow (‘to walk about’) and wrAéw (navigo). The proposed term ‘ protopoda’ is quite as un- fortunate as ‘ cephalopoda,’ since ‘ protopodite’ and ‘protopod’ are already in use for parts of | ) J I crustacean appendages, the former even in the present work. The extension of the term ‘uropoda’ so as to make it synonymous with ‘pleopoda’ would also be unfortunate, since, as now employed, it is a very useful term to des- ignate the modified caudal pleopoda, whether | 1 According to cither Bate’s or Packard’s derivation, this would be more properly written pev'acon, as has sometimes been done, or even pereon. - one, two, or three pairs. In the chapter on development, metamor- phoses, and genealogy, Professor Packard gives a short account of the nauplius form in Phyllopoda as an introduction to Dr. Gissler’s interesting notes in the following chapter, and then briefly discusses the phylogeny of the group, in which he appears to find but one dif- ficulty. He says, — ‘The difficulty is (and this is a point ap- parently overlooked by Fritz Miller, Dohrn, Claus, and Balfour) to account for the origina- tion of the phyllopods at all from any marine forms. The only explanation we can suggest, is that the phyllopods have arisen through Limnetis directly from some orginally marine cladocerous type like the marine forms now existing, such as Evadne. We imagine that when a permanent body of fresh water became established, as, for example, in perhaps early Silurian times, the marine forms carried into it in the egg-condition, possibly by birds or by high winds, hatched young, which, under favor- able conditions, changed into Sida, Moina, and Daphnia-like forms.’’ Professor Packard appears to have over- looked the difficulty of the eggs of any marine cladocerous type of animals surviving a sud- den transfer from salt to fresh water, and the absence of birds in the Silurian, which might well deter the boldest speculator from offering ‘such an explanation ; but when we consider that permanent bodies of fresh water were undoubt- edly formed by the gradual freshening of bodies of salt water cut off from the ocean, and that such bodies of fresh water usually had outlets connecting them with the sea, it is not surpris- ing that Fritz Muller, Dohrn, and others should overlook a difficulty which is no greater for Phylopoda than for other groups of fresh- - water animals. Jn the chapter on his new order, Phyllocarida, and its systematic position, Professor Packard describes the anatomy and development of | Nebalia, and discusses its fossil allies. The appendages of Nebalia bipes are described and fully figured, but on the internal anatomy very little that is new is given. The figures and text intended to elucidate the histology, like most of Professor Packard’s similar work, leave much to be desired. The bibliography consists of a hundred and thirty-eight titles, divided into four sections, | — one for living and one for fossil Phyllopoda, and the same for Phyllocarida. The titles of many of the works referred to are omitted in the bibliography, which is evidently very incomplete ; but its incompleteness is not so annoying as the entire want of system in its arrangement, and the frequency of ty pographi- cal errors. ; Typographical errors are very numerous in all parts of the work ; and many of them cannot properly be charged to the proof-reader, who, however, ought to have corrected blunders like ‘ Yahresbericht’ (several times) and ‘ zoogloi- eal,’ and the inexplicable punctuation of most of the bibliographical references in the system- atic parts of the work. Errors due to careless writing or careless compiling are more com- mon than purely typographical errors, and far more confusing. On p. 813 we have the fol- lowing: ‘‘It is difficult to say whether this is a Limnadia or Estheria, as the description is too brief and inexact to enable us to determine the genus or species. It cannot be a Limnadia, and seems to approximate more closely to Kstheria; though it cannot belong to that genus.’’ On p. 336 it is said that ‘ Schman- kevitch’ found ‘ Branchinecta ferox (Fischer sp.)’ transform by artificial means into Ar- temia; but in reality he found an Artemia change into a Branchinecta, or into what he considered a Branchipus. On p. 337, ‘ Lab- rador examples’ are said to have been taken ‘onthe north side of Hamilton Inlet, Northern Greenland.’ On pp. 513 and 314 the species of Estheriinae not recognizable are inserted between two species of Eulimnadia instead of at the end of the sub-family. Two paragraphs at the bottom of p. 849, under Streptocephalus Sealii, should have been placed under Chiro- cephalus Holmani, on p. 352. On pp. 356 to 358 the genus Leaia is inserted between two species of Estheria. The plates, perhaps the most valuable part of the work, are nearly all lithographs from the establishment of Thomas Sinclair & son, and are apparently accurate representations of the original drawings. ‘The general figures, most- ly drawn by Emerton and Burgess, are excel- lent. The figures of details, drawn by the author, are not always so satisfactory: the figures of the appendages of Apus and Lepi- durus, for example, are very rudely drawn, and badly arranged on the plates. Unfortunately, the amount of enlargement of scarcely any of the figures is given. S. I. Saura. ] | NOVEMBER 16, 1883.] | SCIENCE. The specific distinctness of the American and European brine shrimps. In Professor Smith’s notice of our ‘Monograph of phyllopod Crustacea,’ he states, that, in the portion relating to the above subject, ‘there is certainly con- fusion,’ and quotes two paragraphs relating to the females alone, and finally remarks, ‘‘ but differences like these in statements of observation betray inex- plicable carelessness.’’ After quoting the two paragraphs relating to the females alone, it seems to us a careful critic would have also taken pains to have quoted the longer para- graph relating to the males, which directly follows the first paragraph quoted by our critic. To allow the two paragraphs relating to the females to be so widely separated was an oversight on the part of the author, who, however, thought that he had taken a good deal of pains to show the specific distinctness of the American and European species. Two sets of females from different localities, named by different persons, were examined at different times ; and this ex- plains how the two paragraphs became placed too far apart in the author’s copy. It would have been bet- ter, of course, if the author had added a few words, and dogmatically stated that the two species were undoubtedly distinct. He preferred not to do, or omitted to do, this, but gave in considerable detail, and in as judicial a way as possible, the facts of the ease. At first it was ‘ difficult to find good differential characters’ between the females, and those found are but slight ones. The females of any of the species of Artemia, Branchinecta, or Branchipus, do not exhibit good specific characters; but the males do, as the author attempted to show. If the author failed in directness of statement on this subject, or led to any confusion in any one’s mind, he sincerely regrets it: on the other hand, he doubts whether there were, in the case, reasons for the charge of ‘inexplicable carelessness.’ The paragraph which Professor Smith would have done well to have quoted is the following one: — “Upon comparing a good many males from Great Salt Lake with several, both stained with carmine and unstained, received from Cagliari, Sardinia, through Prof. J. McLeod of Ghent, the European A. salina is seen to be considerably stouter, the head. wider, the eye-stalks longer and larger, and the eyes larger. The frontal button-like processes of the first joint of the claspers are nearly twice as large as in the American species, and a little more pointed, while the claspers themselves are larger and stouter. The legs and sixth endites are of about the same form. The most apparent difference is in the caudal appendages, or cer- copods, which in A. salina are several times larger than in A. gracilis, being in the Sardinian specimens nearly three times as long and much larger than in our species. In this respect, the genus shows a close affinity to Branchinecta. However, in a lot of A. salina © from Trieste, the cercopods are very much shorter than in the Sardinian females, and only a little longer than in our American specimens. These appendages do not differ in the two sexes.” A. S. PACKARD, Jun. or ins TAANT paces AN eae SMITHSONIAN INSTITUTION LIBRARIES UNA 3 9088 00717 1515 WIN Wes gah Day ay anal rahe, iNest, crt i 4s 1 f i f adi Mae ay yes 5 ub Eg oh, LL =F lnyee YAK ati Leah hategi, WI BY)