em SPRY eRe RRL I ie SS a RE gO ee A ae a ae Memoirs of the Museum of Comparative coology AT HARVARD COLLEGE Vou ext, Noo & REPORTS ON AN EXPLORATION OFF THE WEST COASTS OF MEXICO, CENTRAL AND SOUTH AMERICA, AND OFF THE GALAPAGOS ISLANDS, {IN CHARGE OF ALEXANDER AGASSIZ, BY THE U. S. FISH COMMISSION ‘STEAMER ‘ ALBATROSS,” DURING 1891, LIEUT. COMMANDER Z. L. ‘TANNER, U.S. N.. COMMANDING. XXV. THE OPHIURIDA. By C. F. LUTKEN anp TH. MORTENSEN. WITH TWENTY-TWO PLATES, AND A CHART OF THE ROUTE. {Published by Permission of MARsnaLL McDonatp and Gorse M. Bowers, U. 8. Commissioners : : of Fish and Fisheries.] CAMBRIDGE, U.S. A.: Printed for the fAuseum. NoveMBER, 1899, = ro ee ee Memoirs of the Museum of Comparative Zoology ' AT HARVARD COLLEGE. Vi0Ge DO ENG. 2: REPORTS ON AN EXPLORATION OFF THE WEST COASTS OF MEXICO, CENTRAL AND SOUTH AMERICA, AND OFF THE GALAPAGOS ISLANDS, IN CHARGE OF ALEXANDER AGASSIZ, BY THE U. S. FISH COMMISSION STEAMER ‘‘ ALBATROSS,” DURING 1891, LIEUT. COMMANDER Z. L. TANNER, U. S. N., COMMANDING. XXV. THE OPHIURIDE. By C. F. LUTKEN anp TH. MORTENSEN. WITH TWENTY-TWO PLATES, AND A CHART OF THE ROUTE. [Published by Permission of MarsHatt McDonatp and Grorce M. Bowers, U. 8. Commissioners of Fish and Fisheries.] CAMBRIDGE, U.S. A.: Printey for the fAuseum. November, 1899, University Press: Joun Wixson AND Son, CAmpBrincr, U.S. A. PREFACE. Ir was originally intended that the Ophiuride of the “ Albatross” Expedition should be studied by only one of the present authors. The eminent American specialist in Ophiurans, Theodore Lyman, to whom the task would naturally have fallen, was ill, and it was undertaken by Professor Liitken. Having made a preliminary determination and description of almost all the new species, he saw that he should not have time to do the work thoroughly, and, with the permission of Mr. Agassiz, the other author, Dr. Th. Mortensen, was engaged, and we have accomplished it together. The figures were drawn by Dr. Mortensen except Figure 8, in Plate XX., and Plates XXI. and XXII., which were drawn by Mr. Bentzen- Bilkvist, who also lithographed all the figures. We cannot conclude our work without offering him our best thanks, as without his eminent skill the plates would have been far inferior to what they have now become. Much stress has been laid upon making the figures as correct and as distinct as possible. Every one who has to determine Ophiurans knows what trouble bad figures give. Moreover, whenever we have found details which are not sufficiently distinct or correct in the figures, it has always been noted in the description of the species figured. We hope, therefore, that it will be comparatively easy to recognize the species here described. We have given a list of the papers on Ophiurids published subsequently to Lyman’s Monograph in 1882; and finally we have enumerated all the new species with references to the works in which they are described. We think that this will be of some value to those who are working on Ophiurids. THe AUTHORS. CorrnnAcEen, May, 1898. =a THE OPHIURID. I. INTRODUCTION. Tue total number of species of Ophiurids from the “ Albatross” Expedition is sixty-six. Of these one genus and fifty-three species are new. ‘This is truly an astonishingly great number of new species, but such is the case almost everywhere, where more careful researches are made. We need only name the “ Blake,’ the “Caudan,” and the “ Investi- gator.” This gives an idea of what riches of forms must be found in the immense regions of the great oceans, which are still almost unknown. There are now known about one thousand species of Ophiurans. We may safely say that, when all the great oceans and all the tropical shores have been sufficiently well investigated, the number will have increased to about double. The “Challenger” Expedition got only seven species of Ophiurans in the part of the Pacific between Juan Fernandez and Valparaiso (Stations 296, 298, 299), namely: Ophioglypha Lacazei Lym., Ophiomusium Lyman Wyv. Thoms., O. armigerum Lym., Amphilepis patens Lym., Ophiacantha cosmica Lym., O. sentosa Lym., and Ophiothola supplicans Lym. Of these we have found only three among the “ Albatross’? Ophiuridss: Ophiomusium Lymani, Amphilepis patens, and Ophiacantha cosmica. Further, Ophiacantha Normani Lym., which was taken by the “Challenger” in the eastern part of the Pacific, is found in great numbers among the “ Albatross” Ophiuride. The following species were taken by the “ Albatross” Expedition : — 1. Ophioderma panamensis Ltk. 6. Ophiernus annectens n. sp. 2: variegata Ltk. de polyporus n. sp. 3. Ophiozona contigua n. sp. 8. Gymnophiura mollis n. g., n. sp. 4 alba n. sp. we coerulescens n. sp. 5. Ophiernus seminudus n.'sp. 10. Ophioglypha superba n. sp. 98 THE OPHIURIDZ. 11, Ophioglypha abcisa n. sp. 39. Amphiura papillata n. sp. 12. obtecta n. sp. 40. Amphilepis patens Lym. 13. tumulosa n. sp. 41. Ophionereis annulata Lym. 14. plana n sp. 42. nuda n. sp. 15. scutellata n. sp. 43. Ophiochiton carinatus n. sp. 16. nana 0. sp. 44, Ophiacantha cosmica Lym. Lf. - divisa n. sp. 45. pacifica n. sp. 18. Ophiocten pacificum n. sp. 46. inconspicua n. sp. 19. Ophiomusium glabrum n. sp. 47. spinifera n. sp. we 20. Diomedez n. sp. 48. formant Lym. 21. variabile n. sp. 49. moniliformis n. sp. 22. Lymani Wyv. Thoms. 50. costata n. Sp. 23. Ophiactis Savignyi (M. & Tr.). 51. contigua n. sp. 24. profundi n. sp. 52. hirta n. sp. 25. duplicata (Lym.). 53. paucispina n. sp. 26. Amphiura serpentina n. sp. 54. Bardi Lym. 2. gymnogastra n. sp. 5). Ophiomitra granifera n. sp. 28. polyacantha n. sp. 56. partita n. sp. 20. seminuda Nl. sp. 57. Ophiothamnus levis n. sp. 30. brevipes n. sp. 58. Ophiothria spiculata le Conte. 31. gymnopora N. sp. 59. galapagensis n. sp. 32. Diomedee n. sp. 60. Ophiomyxa panamensis n. sp. 33. assimilis n. sp. 61. Sigsbeia lineata n. sp. 34, dalea Lym. 62. Asteronyx dispar n. sp. 35. granulata n. sp. 63. excavata Nn. sp. 36. gastracantha n. sp. 64. plana n. sp. 37. notacantha N. sp. 65. Astroschema subleve n. sp. . 38. Sp. 66. Gorgonocephalus Diomedee n. sp. Four of these species are first described from the Atlantic Ocean or the West Indies, viz. : — Ophiomusium Lymani Wyv. Thoms. Amphiura dalea Lym. Opliactis duplicata (Lym.). Ophiacantha Bairdi Lym. The following species are very closely allied to species from the Atlantic or the West Indies : — Ophiernus seminudus to O. vallincola Lym. Opluernis annectens to O. adspersus Lym. e Ophioglypha divisa to O. mornata Lym. : Amphiura gymnogastra to A. semiermis Lym. Ophocantha paucispina to O. Bartletti Lym. Sigsheia lineata to S. murrhina Lym. THE OPHIURIDZ. 99 Astroschema subleve to 4. clavigera Verr. Ophiozona alba is very closely allied to 0, depressa Lym., from the Philippines. Evidently there are very interesting relations in the geographical distribution of Ophiurids. The material here collected gives some hints of the relation between the fauna of the West Indies and that of the Pacific. However, we find that there is needed yet more information as to the dis- tribution of the species before any definite results can be given. And it should be well remembered that we must study the distribution of every species separately. For the littoral species we refer to LUrKEN, Additamenta ad Historiam Ophiuridarum, Part II. (Vidensk. Selsk. Skrifter Kjébenhavn, 5 Raekke, Mathem. naturv. Afd., Bd. V., 1861), and to Verrii, Notes on the Radiata in the Museum of Yale College, Part II. (Trans. Connecticut Acad. of Arts and Sciences, Vol. I., 1867). Possibly we have made too many new species. It may be doubted whether the two Ophiernus species, seminudus and annectens, are really differ- ent from the two Atlantic species named above. Be that as it may, if only the descriptions and figures are good, there cannot be much harm done: — a few synonyms more, — this fault is easily corrected. We have thought it would be worse, if any species were wrongly referred to a species already _ known, especially in a case where the identifying of such forms usually means that they are found in both the Pacific and the Atlantic Ocean. The classification of the Ophiurids is still in a rather imperfect condition. Not even the families are finally settled, and several of the genera are very insufficiently defined. Lyman, who has described so vast a number of species, had not, unfortunately, much perception of the relations of the forms. Though he had so large and excellent a material, he gives in his great monograph only a very rude grouping of the genera, which affords no idea of their real relations. Bxruw’s classification (19) also scarcely expresses the real relation of all the genera, though no small progress was made thereby toward a natural classification. As one of the present authors (Dr. MorTENSEN) purposes to give later a complete revision of the whole class of the Ophiurids, we shall here still follow the ordinary method, by naming the genera one after another, usually in the accustomed order. 100 THE OPHIURIDA. Il DESCRIPTION OF SPECIES. 1. Ophioderma panamensis Ltk. Lirken: Additamenta ad Hist. Oph., Part II. p. 193. Panama. 1 specimen. 2. Ophioderma variegata Ltk. Plate I. Figs. 1-3. Lirxen: Op cit., Part II. p. 199. To this species we refer a specimen from Panama, although it seems at first sight to differ rather widely therefrom, the disk being almost entirely destitute of the granule with which the species of Ophioderma commonly are covered, and instead thereof being covered with small, irregular, not overlapping scales, among which the primary plates are not to be seen. In all other respects it closely resembles the O. variegata. However, there are seen by closer examination some granules here and there, in spots, where they have been protected from being rubbed off, as especially at the arm-bases on the under side of the disk. It is therefore almost sure that there have been granule covering the whole disk. Also the arm-spines and the tentacle scales have mostly been broken off: This has caused an error in Figure 1: only one tentacle scale is seen there ; after the figure had been reproduced, we found traces of the outer tentacle scale also, so that there will not be any difference from other species of Ophioderma in this respect. The color also corresponds to that of the two specimens of O. variegata, which are pre- served in the Museum at Copenhagen; the arms are colored alternately with dark brown and white (faintly reddish) bands, each band enclosing 2-3 joints. In the figures of this species, (which has not been previously figured,) it is represented without the covering of granule. In the other species of Ophioderma there will be a similar covering of scales beneath the granule. On Figure 1, there is seen at the inner edge of the second ventral plate a pair of small pores, whose significance is wholly unknown to us. The same pores we found in all the species of Ophioderma which we have examined ; — or ~ i THE OPHIURIDZ. 101 in some species there are two pairs of pores, the second at the inner edge of the third ventral plate. One pair was found besides in 0. variegata, in O. brevispina Say, and O. Januari Ltk.; two pairs were found in 0. brevicauda Ltk., O. cinereum M. Tr. (= antillarum Ltk.), lacertosa. Lmk., rubicunda Ltk., and O. appressa Say (= virescens Ltk.). Possibly this may be of systematic importance. We should not be much surprised if 0. brevispina Say (= serpens Ltk.) and O. Holmesti Lym. should turn out to be the same species as O. variegata. Between 0. brevispina and variegata there seems to be no difference except in the color; but as the color is highly variable in these forms, that will scarcely be sufficient for maintaining them as two species. Of 0. Holmesii, Lyman* says, “This species stands between 0. brevispina and O. olivacea.” In the “Challenger” Monograph he makes 0. brevspina and O. olivacea synonyms, but maintains O. Holmesii as a distinct species, without giving further reasons for it. It seems that O. Holmesii is only a larger specimen of O. brevispina ; all these species would thus be reduced to one, whose name should be O. brevispina Say. But we cannot say that with certainty for want of material for comparison. 8. Ophiozona contigua n. sp. Plate VI. Figs. 10-12. Diameter of disk, 10 mm.; width of arms close to disk, 1.8 mm.; length of arms, 35 mm. Five to six mouth papilla on each side of the mouth angle; the outer one very small, the next one much larger than the others, rounded ; the three or four inner ones more or less conical, as is the one on the apex of the jaw. The teeth are pointed. Mouth shield a little longer than broad, with an angle within and outer edge rounded ; lateral sides a little restricted through the genital slits; the outer end is the widest. Side mouth shields short and rather wide, meeting within, almost equally broad in their whole length. First ventral plate very small, five-sided; those beyond a little longer than wide, in mutual contact almost, but not quite, to the end of the arm. Their inner end is truncated, their outer edge strongly curved, or with a rounded peak. Inner laterals re-enteringly curved, outer laterals restricted through the tentacle pores. Farther out on the arm, before they are sepa- * Ophiuride and Astrophytide, Old and New. Illustr. Catalogue Mus. Comp. Zodl., Vol. I. p. 22. 2 102 THE OPHIURIDZ. rated, the ventral plates are rather long and narrow. Side arm-plates with outer edge somewhat thick and prominent; they meet above only in the outer third or half of the arm. Dorsal plates a little wider than long, (some- times a little broader than figured,) rather broadly in contact far out on the arm; their inner edge is much narrower than the outer, concave, outer edge convex, lateral sides almost straight, or feebly re-enteringly curved ; in the outer part of the arm the dorsal plates are triangular. The first dorsal plate is very short; inside that there are some small, irregular, crowded scales, which cannot be regarded as rudimentary dorsal plates. The arms rather stiff, round; the joints a little nodose. Disk covered with stout overlapping scales, among which the primary plates are very conspicuous, making a rosette in the middle of the disk ; they lie close together, not separated by smaller scales, sometimes, however, there are five very small scales between them, joining the central plate. The radial shields are small, only about a third of the radius of the disk, triangu- lar, widely separated through a single series of scales. In the interbrachial spaces there is a rather large marginal plate, which is separated from the radial shields by a series of narrow scales. The under side of the disk is covered by scales similar to the smaller ones on the dorsal side. The geni- tal scale very narrow, but distinct almost in the whole length. The edge of the disk is rather sharp. The genital slits reach to the end of the second arm-joint or to the middle of the third joint, but from that point there is a deep furrow to the margin of the disk, so that it looks as if the genital slits did reach to the margin. No genital papilla. Two rather thick, not pointed arm-spines, about as long as an arm-joint ; sometimes the upper one, sometimes the lower one, is a little longer than the other, sometimes they are equally long. There are spines also on the first two joints. One large round tentacle scale, continuing to the end of the arm; also the inner pores have only one tentacle scale. Color in alcohol: white. Station 3400, 1322 fathoms; 5 specimens. St. 3413, 1360 fathoms ; 1 specimen. 4. Ophiozona alba n. sp. Plate VI. Figs. 7-9. Diameter of disk, 12 mm.; width of arm close to disk, 2 mm.; length of arms scarcely four times the diameter of disk. Four to six short, close set THE OPHIURIDZ. 1038 mouth papillae. The outer one is very small, the next one is the largest of them all, rounded; the next one to three are square, and finally the inner one usually pointed. Sometimes there is a little median papilla below the teeth, but it seems to be typical that there is no median infradental papilla. The four to five teeth are broad, square, or slightly rounded. Mouth shield alittle wider than long, with an acute angle within and outer edge rounded. The inner sides are re-enteringly curved, lateral sides straight, outer corners rounded. Side mouth shields very short and broad, meeting within; their outer end much broader than the inner end. First ventral plate very small, regularly five-sided, with an angle inward. Those beyond a little longer than broad, in mutual contact to the fifth or sixth joint, farther off widely separated by the side arm-plates. The second to sixth have their inner angle truncated, the piece in contact rapidly diminishing in width; those beyond the sixth have an acute angle within. The outer side in the first one or two plates is limited by three straight lines, meeting under obtuse angles; farther off there are only two straight lines, which make an obtuse angle in the median line ; sometimes the outer edge is more rounded. The lateral sides are restricted on the middle by the tentacle pores; inner part re-enteringly curved, outer straight, so directed as to make an acute angle with the longitudinal axis of the arm. Side arm-plates with the sides curved, outer edge rather thick and prominent, rounded; on the three joints in the disk they are wholly straight, outer edge not thickened. Dorsal plates almost rhomboidal. The three to four inner ones are in mutual contact, and have thus their inner angle truncated; from the fourth or fifth they are separated by the side arm-plates, and have an acute angle within ; all the sides are a little rounded. They are rather thick and high, as wide as long. The first dorsal plate has the outer edge much rounded, and is much broader than long. Inside that there is a little plate, which may be con- sidered as a rudimentary dorsal plate; it is in contact with the outer one of that series of scales which separates the radial shields. At the base of the arm there is on each side one rather large and a few small scales. The arm is not very high, oval in cross section. The joints are somewhat nodose, constricted at their inner, thickened at their outer end. The disk is covered with large, flat, partly overlapping scales, among which only a few small ones are seen. The primary plates are very con- spicuous. The central plate is five-sided with an angle to each radius, each side joined by an elongated, rounded scale. The radial shields widely sepa- 104 THE OPHIURIDZE. rated, almost oval, not half the length of the radius of the disk. In the interbrachial spaces there are a median row of larger scales and some smaller ones on each side. Ventral side of the disk covered with scales similar to those on the dorsal side. The edge of the disk rather sharp. Genital scale indistinct, very narrow, reaching scarcely to the end of the second joint. Genital slit short, reaching only to the end of the first joint. Two well developed arm spines, the upper one as long as or a little longer than an arm-joint ; farther out not quite so long as a joint; the ~ lower one a little shorter. The two inner arm-joints have no spines. One large, rounded tentacle scale on the outer side of the pore; the first. to third pair of pores mostly have one or two indistinct scales at the ‘inner side (on the ventral plate). Color in alcohol: white. Several specimens from Stations 3362, 1175 fathoms; 3363, 978 f.; 3366, 1067 £.; 8371, 770 f.; 3400, 1322 f.; 3413, 1360 f. Only unimportant variations to be noticed. The teeth sometimes are serrate in outline, and the same may be the case with the infradental mouth papilla. The mouth shield may be more rounded and a little longer. The ventral plates in some specimens are in contact till the 9th or 10th joint; in younger ones they are so only on the first joints. The central plate some- times is almost round; the genital slits are often very indistinct, much shorter than first arm-joint. Sometimes, but rarely, there is an arm-spine on the second joint, but then only on one side of the arm, and not on all arms of the specimen. . This species is very closely related to O. depressa Lym., but is not very difficult to distinguish from the latter. The mouth shield, side mouth shields, and ventral plates are of somewhat different shape, which will be seen. when comparing the figures of the two species; the same is the case with the disk scaling. The primary plates have a little central boss or tubercle in O. depressa ; in O. alba it is very indistinct, or not at all present. The arm-spines are equally long, half as long as a joint in O. depressa; in O. alba they are about as long as a joint on the inner part of the arm; farther out shorter, only half the length of a joint. Usually the upper one is the longest, but sometimes the lower one is so, sometimes they are equal. All the pores have only one tentacle scale in O. depressa ; the inner first to third pairs of pores have two (three) tentacle scales in O. alba. This character seems to be of most importance; however, it might well be that also in THE OPHIURIDZ. 105 QO. depressa there are really two tentacle scales at the inner pores. Often the outer tentacle scale in O. alba wholly covered the inner, which then could only be seen when the former was removed. It may be that they will turn out to be the same species; at present we dare not declare them to be so. (O. depressa was taken near the Philippines, in 500 fathoms.) 5. Ophiernus seminudus n. sp. Plate V. Figs. 10-12. # Diameter of disk, 20 mm.; width of arm close to disk, 3.6 mm.; length of arms, c. 5 times the diameter of the disk. Nine mouth papilla to each side of the mouth angle; the three outer ones are on the side mouth shields, and on the first ventral plate ; they must be considered as the papille of the second mouth tentacle; the middle one of these is especially large, rounded. The rest of the papillew are short, square, close set. At the apex of jaw, below the teeth, there are sometimes two or three small conical papillae, some- times none. Some specimens have the inner mouth papille pointed and longer than the outer ones; on the apex there also may be two rather large conical papille, or only one larger of the same form as the teeth; these are five in number, long, pointed, lanceolate. Mouth shield more broad than long, 1.5:1, with an obtuse angle within and outer edge straight, the sides strongly produced, rounded. Side mouth shields rather broad, meeting within. First ventral plate hexagonal; the rest of the ventral plates with inner end truncated, outer edge curved; lateral sides, both inner and outer part, re-enteringly curved, the latter on account of the tentacle pores. They are a little broader than long, all in mutual contact. Farther out the proximal part of the ventral plates becomes narrow and rather long, stalk-like. There is a rather distinct keel along the median line of the ventral plates. The side arm-plates do not meet either below or above ; their outer edge is not prominent. Dorsal plates twice as broad, as long, feebly keeled, with inner edge a little concave, outer edge correspondingly rounded, lateral sides straight; they are broadly in contact, the inner edge being incon- siderably narrower than the outer edge. Far out on the arm they become somewhat longer and narrower. The four to six first dorsal plates are more or less rudimentary; the sides of the arms along these rudimentary plates are 106 THE OPHIURIDZ. naked. ‘The arms are not wider outside the disk than on the part enclosed in the disk; they are rather high, rounded, triangular in cross section. The central part of the disk is covered with a naked skin, in which only some few very small, widely spread plates are seen (in dried specimens). Along the margin the disk is covered with small, irregular, but distinct scales, which are also found along the margin of the radial shields. These are rather large and conspicuous, almost as long as half the radius of the disk ; they are oval in outline, only the outer edge is almost straight. Usually they are widely separated by several rows of scales, sometimes only by one row of rather large scales. No marginal plate in the interbrachial space, and of course no primary plates. The whole under side of the disk covered with very small overlapping scales. Sometimes there are a few grains on the disk, especially round the radial shields. No genital scales distinct, no papille along the large genital slits, which reach to the margin of the disk. Only two very short arm-spines, sometimes three, in the inner part of the arm, and farther out only one; the upper one is usually a little longer than the other. They are not inserted on the outer edge of the side arm- plates, but a little below, on a little elevation; they only reach to the outer edge of the side plate. The tentacle pores are large, and very conspicuous ; the first 4-5 pairs have two papille at the distal edge, one wide and flat, the other short, rounded. Farther out there are two rather elongated, pointed scales at the proximal edge of the pore, and these continue in the whole length of the arm. Color in alcohol: gray, with a bluish tint. Several specimens from Stations 3360, 1672 fathoms; 3398, 1573 f.; 8399, 1740 f.; 3400, 1822 f.; 3414, 2232 f This species is very variable as to the form of the plates, especially mouth and side mouth shields; it is rare to see them so regular as in the * figure, which however must be regarded as the typical form. Often they are broken or quite irregular in outline. This is no doubt due to the feeble calcification. One specimen has two-three small papilla at the outer edge of the radial shields, as a rudimentary arm-comb. O. seminudus is very closely related to O. vallincola Lym., and perhaps it is really the same species. Judging from the figures given by Lyman (Chal- lenger, V., Plate XXIV. Figs. 16-18), they are not identical: the mouth papilla, mouth shield, side mouth shields, first ventral plate, the inner dorsal we we & THE OPHIURIDZ. 107 plates, the granular covering of the disk and the three arm-spines being all different. On closer examination, however, none of them are very solid. The mouth papille# are not quite in accordance with Lyman’s description, so they had better be disregarded. Asa whole they seem to have no specific importance in this genus. Mouth shield and side mouth shields are very different from the same parts in our figure of O. seminudus ; but there is so much variation among the specimens that there cannot be much weight given to this; thus, the side mouth-shields may have the same form as those in Lymay’s figure of 0. vallincola. In the mouth shield there may be found a distinct character; in O. seminudus there is always a restriction at the outer edge; in O. vallincola that seems not to be the case. The first ventral plate is of rather different shape, but in many of our specimens its form is quite indistinct. The inner dorsal plates are not rudimentary in O. vallincola, but in O. seminudus this feature is not always so prominent as in the specimen figured, however always distinct. It may further be remarked that the naked space is seen distinctly only in dried specimens. The granular covering was wholly wanting in many of LymMan’s specimens of O. vallincola ; in O. seninudus it is only very scarce in some few specimens ; most of them are quite naked. 0. vailincola has three arm-spines in the same place as and similar to those in O. seminudus, which has commonly two, except at the inner joints; but sometimes also the latter has three arm- spines to about the middle of the arm. Finally, the outline of the disk is different in the two species. The large angular plates seen along the genital slits in Lyman’s figure of 0. vallincola are the genital organ’s, seen - through the skin; the like was also seen in O. seminudus. We think it best to make a separate species of this Pacific form, as there seems not to be sufficient evidence that it is identical with the Atlantic form. But certainly they must be very closely related. 6. Ophiernus annectens n. sp. Plate V. Figs. 4-6. Diameter of disk, 13 mm.; width of arm close to disk, 3 mm.; length of arms about seven times the diameter of the disk. Eight to ten mouth papillee to each side, the three or four inner ones conical, the outer rounded or square. The two at the apex mostly longer than the rest, but here much variation exists: sometimes there are more short and broad papilla, quite 108 THE OPHIURIDZ. | irregularly placed, sometimes three rather large. The four to five teeth are long, rounded, almost club-shaped, different from those in O. seminudus. Mouth shield a little longer than wide, with a restriction at the outer end, which thus looks almost like a little stalk. Side mouth shields rather long, much broader without than within, where they just meet. First ventral plate of the same form as those beyond; they are as long as broad, with outer edge curved, inner end truncated; both inner and outer laterals deeply re-enteringly curved, the latter on account of the tentacle pores. The inner end of the ventral plates, especially of those farther out on the arm, looks like a short stalk, and is some- what elevated, making a keel along the median line of the arm. The ventral plates are all in mutual contact and of the same form in the whole length of the arm. The side arm-plates very broad and flat, with outer edge sharp, rounded in outline; from the tentacle pore to the mar- gin of the arm runs a slight elevation, parallel to the outer edge of the side-plate ; at the outer end of this elevation the arm-spines are inserted. The dorsal plates are widely in contact in the whole length of the arm; they are more than twice as broad as long, with a feeble keel. Inner and outer edge curved, the former concave, the latter convex; the lateral sides straight. Outer edge a little wider than the inner edge. One or two of the inner dorsal plates mostly a little narrower than the rest, and there is then a little naked space at each side of them. The arm is very flat and wide, lenticular in cross section. The arm-joints enclosed in the disk are narrower than the first free joints; farther out the arm again becomes narrower. The inner part of the arm (3-4 first joints) rather deeply hollowed in the median line. The disk is wholly covered: the inner part by a close granulation, beneath which there are some indistinct scales, the outer part by the radial shields and distinct small scales, the latter mostly covered with grains. The naked radial shields are widely separated by one or more irregular rows of scales; they have the form of an almost rectangular triangle, about as long as half the radius of the disk. In the interbrachial spaces the disk widens a little, outside the radial shields. No marginal or primary plates. The ventral side of the disk is covered on the outer part with rather distinct, overlapping scales, on the inner part with a close granulation, beneath which the skin is almost naked. No genital scales distinct, no papillz along the wide genital slits, which reach to the margin of the disk. Two arm-spines: the upper one about as long as a joint, the lower not | t A i THE OPHIURIDZ. 109 half so long. They are inserted close together at the side edge of the arm, not at the outer edge of the side arm-plates. The three inner pairs of tentacle pores with one wide and two small papille at the distal edge; from the fourth to the end of the arm there are two distinct elongated scales at the proximal edge. Color in alcohol: gray, with a bluish tint, arms white. 39 specimens from Station 3402, 421 f., most of them not well preserved. Only unimportant variations to be noticed. This species is very closely related to 0. adspersus Lym., perhaps really the same species; however, as with 0. seminudus and O. vailincola, it seems to us best to keep them separate for the present. There are only small dif- ferences to be noticed. The mouth shield is a little different in form, and the side mouth shields are separated within in O. adspersus, meeting in O. annectens. But there cannot be much weight given to this, as the mouth region shows considerable variation in this genus. First ventral plate is swollen in OQ. adspersus, not in O. annectens. The most important difference, however, is found in the radial shields; in O. adspersus their inner end is covered with grains, in O. annectens they are quite naked, also their form is somewhat different; and the radial shields are of importance as to the specific differences in this genus. The arm-spines are somewhat longer in O. annectens than in O. adspersus; the upper one about as long as a joint in the former, only half that length in the latter. In other respects they are entirely alike. It seems then quite possible to distinguish these two forms, but they are very closely related. It is interesting thus to find in the Pacific two species of Ophiernus cor- responding to the two Atlantic species. A third species from the Atlantic, O. abyssalis, was described by Koruier (66) and further (67) recorded from the Indian Ocean, where also O. vallincola was found (Lyman). A third species is also found in the Pacific, but this species and O. abyssalis do not seem to be closer related to each other, or to any of the other known species. 7. Ophiernus polyporus 1. sp. Plate V. Figs. 7-9. Diameter of disk, 14 mm. ; width of arm close to disk, 4.5 mm.; length of arms unknown, but certainly about as in 0. annectens. Ten (9-11) mouth papille on each side of the mouth angle; the outer ones being really the vo 110 THE OPHIURIDZ. scales of the second mouth tentacle; the inner ones are pointed, conical, the outer rounded; usually two, sometimes only one at the apex, below the long club-shaped teeth, which are four or five in number. Mouth shield triangular, with outer end restricted, looking like a short stalk; corners rounded; a little longer than broad. Side mouth shields much broader without than within, where they meet. First ventral plate indistinct, those beyond a little longer than wide, with outer edge curved and inner end truncated. The lateral sides much re- stricted: the outer part by the tentacle pores, the inner part by another pair of pores, which give the ventral side of the arm a very curious appearance. By these two pairs of pores to each joint the ventral plates are so restricted as to appear like a narrow median band along the under side of the arm. Farther out on the arm these pores become smaller, and from about the middle of the arm they wholly disappear. The side arm-plates do not meet either below or above; they are very wide, with outer edge sharp, finely curved in out- line. From the tentacle pore to the margin of the arm there is a slight elevation, parallel to the outer edge of the plate. At the outer end of this elevation the arm-spines are inserted. The dorsal plates are more than twice as long as broad, with outer edge a little wider than inner edge, both slightly curved; lateral sides straight. They have a feeble keel. The -three or four inner ones more or less rudimentary, with a naked space on each side. The arms are very wide, flat, triangular in section; their under side is deeply hollowed in the median line in the inner part, farther out it is flat. The joints enclosed in the disk are considerably narrower than those outside the disk ; farther out the arm gradually becomes narrower again. The dorsal side of the disk is covered almost wholly by the large naked radial shields, which are as long as three fourths of the radius of the disk ; the little central space is covered with a close granulation, beneath which no scales are seen. The radial shields are in contact in their whole length, or partly separated by a row of very small scales; in the interbrachial spaces they also are in contact, only sometimes separated by a narrow line of granule. Their abradial margin is covered with some indistinct scales, which are again covered with granule. The outer edge is doubly curved, and the outer corner is somewhat produced outwards. Outside that there are again some mostly naked scales; the disk is thus considerably produced in each interbrachial space. Under side of the disk covered along the margin and the genital slits with very indistinct small scales; in the middle part THE OPHIURIDZ. 111 there are no scales, the skin is covered only with granule. No distinct genital scales. Two sharp, pointed arm-spines, at the edge of the arm; the uppermost | about as long as a joint, the lower much shorter. The three to four inner tentacle pores with a broad and a small papilla along the distal edge of the pore, those beyond with two rather large scales of the common form at the proximal edge. Color in alcohol: gray, the radial shields usually with the margin white. Several specimens from Stations 3356, 546 f.; 3418, 660 f.; 3424, 676£,; 3425, 680 f. The sole specimen from the latter station has the pores much smaller than usual. The significance of these pores is quite unknown to us; they would best be examined on sections of the arm, but the specimens are too badly preserved to be used for histological researches. The pores seem not to be covered with skin. In a single specimen of O. annectens we have found some few small pores and depressions, corresponding to the pores in 0. polyporus. GYMNOPHIURA ». ¢. This genus is closely related to Ophioglypha, the sole important difference being that the dorsal side of the disk is covered with a thick naked skin, in or beneath which only a few, if any, irregular widely spread scales are hid- den. In younger specimens these scales may be somewhat more distinct. The outer ends of the radial shields are naked. In all other respects, mouth papille, teeth, tentacle pores, arm-comb, etc., it closely resembles Ophioglypha. As that genus already in its present limitation is rather too wide, it seems to us perfectly justifiable to constitute a new genus on this form. From the genus Ophiopleura, whose disk is also covered with a thick skin, it is well separated; Ophiopleura has short genital slits, which do not reach the margin of the disk; there is a complete covering of small distinct scales beneath the skin, and there is no arm-comb. 8. Gymnophiura mollis n. sp. Plate VII. Figs. 7-9. Diameter of disk, 25 mm.; width of arms close to disk, 5.5 mm.; length of arms about five times the diameter of the disk. Five or six mouth papillee to 112 THE OPHIURIDZ. each side, short, rounded, rather close set ; the outermost one is wider than the rest, and separates the pore of the mouth tentacle from the mouth space ; that on the apex of the jaw is scarcely longer than the rest. Mouth shield hourglass-shaped ; an obtuse angle within, outer edge straight, lateral sides deeply restricted by the inner end of the genital slits; the corners rounded. Side mouth shields rather short, almost equally wide in their whole length, meeting within. Mouth angle not prolonged. First ventral plate not much smaller than the following ones, polygonal, with outer edge strongly curved, inner edge straight. The following ventral plates a little broader than long; the second is longer than the rest, though not so long as broad. Inner and outer edge are strongly curved, the former concave, the latter convex. ‘The lateral sides a little re-enteringly curved through the tentacle pores. The five inner ventral plates are in mutual contact in their whole breadth; from the sixth, the piece in contact becomes rapidly narrower, and from the 8th-9th joint they are wholly separated. ‘Their form then rapidly alters: at first they have an acute angle within, but this soon disappears; they have then a slightly rounded edge within, whereas the outer side is produced into an angle, with the tip rounded. The plates are thus triangular, with the top turned outward, and lie almost wholly in the base of the next joint, not in that to which they really belong; in this form they continue to the end of the arm. The side arm-plates are flat, straight, outer edge not prominent; on the dorsal side they are separated to the end of the arm. The dorsal plates are four-sided, in the inner part of the arm twice (or more) as broad as long, farther out they gradually become narrower, and towards the end of the arm they are twice as long as broad. They are in contact in their whole width, the inner edge being only inconsiderably narrower than the outer. All the sides are almost straight. The first three dorsal plates are of a somewhat different shape: the first is crescent-shaped, convex within, concave without; the second has inner and outer edge straight, the latter the widest; the third has inner edge straight or slightly concave, outer edge convex; this is the widest of all the dorsal plates. The three described plates are very short; along their sides is a somewhat elevated line, which bears some small, not very distinct papillw, the secondary arm-comb. Inside these three plates there are yet one or two very small rudimentary dorsal plates. Arms thick and round. Disk covered with a thick naked skin, through which only the radial ‘ j ; ] j q THE OPHIURIDZ. 113 shields are seen as large ribs. They are long, narrow, widely separated ; their outer third part is naked and smooth, the rest is covered (beneath the skin) with irregular scales, which are firmly united with them, their surface thus being rough. The outer edge of the radial shields is straight, sharply ° cut. Some spread scales are found between the radial shields, especially at their outer end. For the rest, only some few small, irregular widely spread scales may be seen in the skin of the disk, and they can only be seen in dried specimens. The ventral side of the disk is covered with rather dis- tinct overlapping scales, which are not enveloped in thick skin. Genital slits very wide and long, reaching almost to the dorsal side of the arm. The genital scale is distinct only towards the margin, grows rather broad as it passes to the dorsal side, where it bears the arm-comb, which consists of short rounded papille; about eight to ten are to be seen from above. The genital papille short, conical. Seven to eight short, equally spaced arm-spines Tentacle pores large in the inner part of the arm, but soon diminishing in size, distinct only to about the middle of the arm. First tentacle pore seemingly opening into the mouth space, but separated therefrom by the outermost mouth papilla. Nu- merous long tentacle scales. First pair of pores has 5-6 on inner (adradial), 6-8 on outer (abradial) side; the second has 4 on inner, 6-7 on outer side. They are then gradually reduced in number; on the 9th-10th pore there are no more scales on the inner side; those on the outer side aré reduced to a very small one at about the 20th joint, and this one continues to the end of the arm. Among the numerous large specimens but little variation is found. At the apex of the jaw there may be some more mouth papille, irregularly crowded, so as to resemble tooth papille, but they are not so really. The secondary arm-comb is often wanting, and often it is only one or two of the first dorsal plates, which are of another shape than the rest. The number of arm-spines varies not a little; the typical number is 7-8, but it may be reduced to 5, or raised to 9 or 10. In younger specimens (diameter of disk, 13 mm.) there is a rather com- plete covering of plates on the dorsal side of the disk, under the skin, but the scales are very irregular and indistinct in outline; a central plate is distinct, also five other primary plates, which lie between the inner ends of the radial shields. In still younger specimens presumably the primary plates will be large and cover most of the disk. Only the first dorsal plate 114 THE OPHIURIDZ. has a shape different from that of the rest. Not so many tentacle scales as in larger specimens; five arm-spines. No distinct secondary arm-comb. Color in alcohol: gray, with a faintly bluish tint on the skin; the radial shields appear as white lines. In dried specimens the naked skin is almost black. Stations 3392, 1270 f.; 3400, 1322 f.; 3418, 1360 f. 9. Gymnophiura corulescens n. sp. Plate VII. Figs. 4-6. Diameter of disk, 21 mm.; width of arm close to disk (without spines), 5 mm.; length of arms unknown, but evidently as in G. mollis. Six (0-7) short, not very close set, more or less conical mouth papille, one longer at the apex. The outermost papilla does not separate the first tentacle pore from the mouth space. Mouth shield a little longer than broad, with a very obtuse angle (or rounded) within and outer edge rounded; the lateral sides restricted at the inner end, then straight until the outer edge; the inner part of the mouth shield is thus broader than the outer part; sometimes it is quite irregular in outline. Side mouth shields rather short, equally broad without and within, sometimes meeting within, sometimes more or less widely separated by a naked space. First ventral plate a little smaller than the following, with the sides rounded, inner edge straight, outer edge curved inward; in other specimens it is more hexagonal, with outer edge straight; sometimes it is divided by a median line. The following ventral plates are about twice as broad as long; they are in mutual contact until the c. 8th joint, the piece in contact becoming gradually narrower. The outer edge is almost straight, only with a little rounded peak in the median line; the inner edge straight on the inner plates; the lateral sides slightly sigmoidly curved, making an angle of about 45° with the longitudinal axis of the arm. The outer edge is much broader than the inner edge. From the c. 9th joint there is an angle within, but that gradually disappears farther out, and the whole inner side of the ventral plate is then rounded or almost straight, the plate being thus very short but broad. Side arm-plates with outer edge a little prominent; they seem to be widely separated above to the end of the arm. The dorsal plates more. than twice as broad as long, becoming gradually longer and narrower farther out on the arm; they have a feeble keel. Outer and inner Dad THE OPHIURIDZ. 115 edges double curved, the former convex, the latter concave, lateral sides straight; outer edge a little wider than the inner edge. The first three or four dorsal plates more or less rudimentary, with a naked space at the sides. No distinct incisure in the disk at the arm-basis. Arms very wide and flat, slightly rounded below, with a keel above. Dorsal side of the disk rather curious looking: there is a little naked central space, which in each radius and interradius is prolonged towards the margin, thus taking the form of a star. A broad band along the margin is covered with small, but rather distinct, overlapping scales, which also cover the inward prolongations between the rays of the naked central space. Radial shields very small, triangular, with outer edge curved, widely separated. Under side of the disk also covered with small, distinct, over- lapping scales. Genital scales distinct only in their outer part, where they pass to the dorsal side of the arm; here they appear as a rounded plate, bearing an arm-comb, which consists of 6-8 very long and thin pointed papilla. Genital papille also long and needle-like. Three well developed pointed arm-spines, the lowermost one about as long as an arm-joint, the two upper ones about as long as two joints. The tentacle pores seem to be distinct in the whole length of the arm; first pair opens into the mouth slit. Only on the first joints the pores are in contact with the outer corners of the ventral plate ; farther out they are distinctly separated from it. (In G. mollis the pores lie along the sides of the ventral plates.) Tentacle scales rather numerous, long and flat; first pair of pores has 4-5 on each side; those on the inner side already have disappeared from the c. 6th joint; those on the outer side diminish in number: from the c. 9th joint three, from the c. 12th two, and from the c. 20th only one scale, which seems to continue to the end of the arm. Color in alcohol: gray, with a distinct bluish tint, especially on the naked parts of the disk. : Five large specimens from Station 3431, 995 f.; from Station 3429, 919 f.; there are some broken arms of this species. The two species of Gymnophiura here described are not very closely related, and might even be regarded as types of two subgenera; however, before more species of this genus are known, such subdivision is not needed. Ophioglypha inermis Lym. possibly is nearly related to G. cwrulescens. Of this species Lyman says (Challenger, p. 12) that it “stands on the limit of Ophioglypha.” If it should turn out to belong to the genus Gymnophiura, 116 THE OPHIURIDZ. the definition of this genus must be somewhat altered, as it has the disk wholly covered with thin scales; or perhaps G'. caulescens should be referred to Ophioglypha together with O. inermis, and G. mollis alone remain in the genus Gymnophiura. For the present, we are unable to say anything about it definitely. 10. Ophioglypha superba n. sp. Plate I. Figs. 4-8. Plate VII. Fig. 4. Diameter of disk, 25 mm.; width of arm close to disk, 5.6 mm.; length of arms, c. 100 mm. Three or four short mouth papille on each side, close set, rounded; that on the apex of jaw mostly concealed by the innermost papillw on the sides. Mouth angles rather long. Mouth shield very prom- inent, thick, inner end narrow, with an angle; outer end broad, rounded, bending towards the dorsal side; a little longer than broad. Side mouth shields short, rather broad, meeting within. Ventral plates in close contact in their whole breadth on the first c. 10 joints, separated only from the c. 15th joint; their form is almost regular hexagonal, with inner and outer side longest. Farther out on the arm they have an angle within and outer edge curved. They are broader than long. The inner ones are somewhat hollowed, almost saddle-shaped, the outer ones flat. Side arm-plates short, rounded, meeting below from about the 15th joint, separated above almost to the end of the arm. Dorsal plates almost of the same shape as the ventral, on the inner part of the arm, farther out more elongated; they are broadly in contact. The first 4-5 thick and swollen; in the rather deep incisure of the disk there are seen one or two rudimentary dorsal plates. The arms are very thick and high. The disk is covered with large, thick, swollen polygonal plates, among which the primary plates are not conspicuous. The radial shields rather large, with a notch on their outer end; they are in contact in most of their length, only their inner part being separated by an elongated plate. No great marginal plate in the interbrachial spaces. - Under side of the disk bending towards the dorsal side, the edge of the disk being very high and abrupt (Fig. 6), covered by several thick plates and by the large genital plates, which, especially at the upper side of the arm, form a pair of con- spicuous plates outside the radial shields, bearing the well developed arm- THE OPHIURIDZ. al] comb. The papille along the genital slits, which begin at the inner end of the mouth shield, are short, close set, square, almost as large as the papilla of the arm-comb; c. 8 papillw to be seen from above (Figure 5 shows a little too many). Often some of the papilla are smaller than the others (regenerated ?), Figure 7. There is a secondary arm-comb (Plate VII. Fig. 4), consisting of a row of papilla along the upper part of the outer edge of first side arm-plate, (that is to say the first which reaches the dorsal side of the arm,) and on a little supplementary plate, which lies at the upper end of this side plate. Four quite rudimentary, equally spaced arm-spines. Tentacle pores large, distinct to the end of the arm, first pair opening into the mouth space. Numerous tentacle scales: the first pore with five to six on the outer (abra- dial), four to five on the inner (adradial) side; second to third pore with four to five on outer, four on inner side; fourth pore with four to five on outer, three on inner side; fifth to eighth with four to five on outer, two on inner side; ninth to about the fifteenth with three to four on outer, one on inner side. From this point there are no papille on inner side, two or three on outer side, and these continue to the end of the arm. The outermost of the papille on the inner side is larger than the others; of those on the outer side the same is the case with the first pore; on the second pore the inner- most papilla is the largest, and from the third pore they are almost all equally large. The direction of the pores gradually alters farther out on the arm: on the inner part they are at an angle of c. 45° with the longitudinal axis of the arm, farther out they are at right angles with it. Color in alcohol: grayish white. Stations: 3431, 995f., 5 large specimens; 3419, 772 f., 1 large specimen. ll. Ophioglypha abcisa n. sp. Plate Il. Figs. 1-3. Plate V. Fig. 3. Diameter of disk, 7 mm.; width of arm close to disk, 1.4 mm.; length of arms unknown, as they are broken in all the specimens at hand. Five short, square, close set mouth papille on each side of the mouth angle, one pointed on the apex of jaw. Mouth shield large, with an acute angle within, outer edge rounded, lateral sides restricted; the outer part is much broader than the inner part; a little longer than broad. Side mouth shields very long and narrow, meeting within. 4 118 THE OPHIURIDZ. The first three ventral plates in contact, those beyond widely separated ; all with outer edge rounded. First ventral plate triangular, almost as large as the next one; second and third with inner end truncated, the rest with an angle within; lateral sides re-enteringly curved. The whole under side of the arm rounded. Side arm-plates long and almost straight, meeting below from the third, above from the second (free) joint. Dorsal plates triangular, with all three sides a little curved. Between the papille of the arm-comb are seen one or two very small dorsal plates, and one larger with inner end truncated. The disk is covered with rather large, irregular, overlapping scales, among which the primary plates are not very distinct. Radial shields not much larger than the other scales, meeting broadly without, the one over- lapping the other; inner ends separated by one or two scales. In the interbrachial spaces there are two great scales, which connect the radial shields of each two adjoining arms; at the margin of the disk there are more small scales. The margin of the disk very high and abrupt, no sharp edge between ventral and dorsal side. The ventral side of the disk covered almost by the mouth shield alone. Genital scale large, growing gradually broader outwards, where it passes to the dorsal side of the arm ; here it makes a conspicuous plate outside the radial shield, bearing the arm- comb. Papillze along the genital slits short, square, and close set; at the sides of the arm they gradually become long and pointed, and make then a very well developed arm-comb; 8-10 papilla visible from above. There is a secondary arm-comb, consisting of shorter pointed papills, inserted on a little supplementary plate at the upper end of first side arm-plate, which reaches the dorsal side of the arm (Plate V. Fig. 3). Three, on the first (free) joints four, equal, evenly spaced, rudimentary arm-spines. Tentacle pores large, distinct in the whole length of the arm, as far as can be judged from specimens with broken arms. First pore not opening into the mouth space. Tentacle scales: first pore with two or three on each side; second and third, with three on each side ; fourth, with two or three on outer, two on inner side; fifth, with one on each side; the following with only one scale, on the outer side. Color in alcohol: gray. Seven almost equally large specimens, from Station 3370, 134 f. The other specimens differ very little from the one described. Only the number of tentacle scales is somewhat variable, there being often 4—5 papillee on the inner side of the second to fourth pore. THE OPHIURIDZ. 119 12. Ophioglypha obtecta n. sp. Plate Il. Figs. 7-9. Diameter of disk, 6 mm.; width of arm close to disk, 1.8 mm.; length of arms, c. 25 mm. (the ends broken off). Four short, close set mouth papille to each side of mouth angle, the outermost very broad, the innermost pointed, as is that on the apex of jaw. Mouth shield hourglass-shaped, with an obtuse angle within, outer edge rounded; longer than broad. Side mouth shields long, narrow, equally broad, meeting within. Ventral plates separated from the fifth, the four inner ones more or less broadly in contact. First ventral plate with outer edge strongly rounded and with a truncated peak within; not much smaller than the next ones. They have all the outer edge rounded; second to fourth (fifth), with inner end truncated: from the fifth they have an angle within. Inner and outer laterals re-enteringly curved, the latter on account of the tentacle pores. The three or four first plates are somewhat hollowed along the median line. Side arm-plates with outer end a little prominent, meeting below from the 4th joint, above only from about the 14th. Dorsal plates rectangular, the innermost as broad as long, becoming gradually narrower farther out; from the 13th-14th joint they are triangular, with a very acute angle within, and from here they are separated by the side arm-plates. The sides of these rectangular plates are a little concave. Disk scaling rather peculiar: the primary plates are round and thick, and between them there are small, very indistinct scales. Radial shields con- spicuous, almost egg-shaped, meeting in their middle part, separated within by the disk scales, without by the two first rudimentary dorsal arm-plates. No great marginal plate in the interbrachial spaces. Ventral side of the disk almost wholly covered by the mouth shields, only a few small scales besides that; the margin of the disk is very high and rather abrupt, with- out any sharp edge between ventral and dorsal sides, covered by small scales. Genital scales rather large, especially their outer end, which passes to the dorsal side of the arm. The papillx along the genital slits are few and very small, rounded; as they pass to the dorsal side of the arm they become longer and pointed, making a well developed arm-comb, of which 6-7 papille are seen from above. The edge of the genital plate is here delicately furrowed. No secondary arm-comb. 120 THE OPHIURIDZ. Three equal, evenly spaced, rudimentary arm-spines. Tentacle pores large, distinct to the 16th—20th joint, presumably continuing to the end of the arm. First pore not opening into the mouth space. Tentacle scales: first to fourth pore with two on each side; fifth and sixth with two on outer, one on inner side; from the sixth or seventh there are none on the inner side, two on the outer side, and from the ninth or tenth there is only one on the outer side. Color in alcohol: gray. Only three specimens: that described from Station 3400, 1822 f.; further one from Station 3375, 1201 f.; and one from Station 3413, 1360 f. The last two specimens are larger: diameter of disk, 10 mm. Side arm-plates meeting below only from the sixth joint, On one specimen the scaling on the margin of the disk is rather incomplete, naked spaces being seen between the scales. The other has 5-6 mouth papille; first tentacle pore has generally three scales on each side, the other pores as above described, only that the scale on the inner side may continue farther out. Upon the whole the three specimens differ very little from one another. 13. Ophioglypha tumulosa n. sp. Plate I. Figs. 9-13. Diameter of disk, 31 mm.; width of arm close to disk, 6 mm.; length of arms ¢c. 5 times the diameter of the disk. Eight short, close set mouth papilla on each side, the two outermost rather broad, the two innermost conical; one pointed at the apex of jaw. Mouth shield almost square, an obtuse angle within, outer and lateral sides straight, the corners rounded. Side mouth shields long, narrow, meeting within. First ventral plate almost oval, though with an angle on each side. The form of the following plates rather complicated. The second to third are polygonal, wider without than within. The second has the outer edge straight or a little concave; on the third it is convex. From here the ventral plates gradually take the form seen in Figure 12. Farther out they become triangular, with an angle within, outer edge rounded, partly with a little peak in the median line, lateral sides faintly sigmoidly curved. The first two are broadly in contact; from the third, the part in contact becomes narrower, and from the 7th to 10th joint they are separated. The side arm-plates are almost straight, outer edge somewhat prominent, on large THE OPHIURIDZ. 121 specimens, not on the small ones; they are widely separated above almost to the end of the arm. The dorsal plates are short and very broad, roof- shaped, outer edge somewhat concave; they are in contact in almost their whole breadth; farther out they become narrower, more elongated. In the rather deep incisure of the disk are seen 3-4 dorsal plates, not very rudi- mentary. The arms are very high on the dorsal side, flat on the ventral side, almost triangular in cross section. Disk covered with rather small, but thick and swollen scales; on the central part only some few of the scales are swollen, towards the margin they are all so. Primary plates inconspicuous. Radial shields rather small, but also thick and swollen, therefore very conspicuous; they are almost ege- shaped, widely separated by several irregularly arranged thick scales, No large marginal plate in the interbrachial spaces. Ventral side of the disk covered with similar thick scales, though not quite so large as those on the dorsal side. Edge of the disk rounded. Genital plates small, distinct only at the outer part of the disk ; they do not extend far upwards to the dorsal side of the arm, only to the outer corner of the radial shields; the arm-comb there- fore is very inconspituous, far from reaching the median line at the arm- basis; only 4-5 papillz to be seen from the dorsal side. Papille along the genital slits well developed, close set; at the inner end of the slits they are irregularly pointed, farther out they become more square, as are the papille of the arm-comb. Usually they are somewhat thickened at their basis. There is no secondary arm-comb, though sometimes there are one or two small papille between the end of the side arm-plate and the dorsal plate. Three small arm-spines, the two lower ones rather close together, the upper one apart, not distinctly longer than the other. The outer edge of the side arm-plate is somewhat curved outwards between the two upper spines; Figure 13 does not give that well. Tentacle pores of the inner part of the arm large and conspicuous, farther out they rapidly diminish in SIZe ; from c. 10th joint they are quite rudimentary (or wanting), but one tentacle scale continues almost to the end of the arm. First pair of pores apparently opening into the mouth space, but in fact it is separated from it by the out- ermost mouth papille ; c. 8 tentacle scales on each side. The second pair has 5-6 on inner, 6—7 on outer side, and then the number of scales gradu- ally diminishes ; from about the tenth joint there is only one scale on the outer side, none on the inner side. At the outer end of each pore there lies a little but distinct plate, which 122 THE OPHIURIDZE. connects the ventral plate with the side arm-plates of the same joint, outside the pore (Fig. 12). Also at the first pore this plate is found, but here it lies proximally to the ventral plate and usually bears the two outermost tentacle scales at the inner side of this pore (not sufficiently clear in Fig- ure 9). This plate is distinct only to about the 10th joint, diminishing in size at the same rate as the pores. Perhaps it is to be looked at as a modi- fied tentacle scale. This plate is found also in Ophioglypha plana. Color in alcohol: pale gray. Younger specimens — (Figs. 9, 10), diameter of disk, 12 mm.; width of arms close to disk, 2.6 mm. — differ from the full grown specimens in not having the scales thick and swollen, but rather flat and small, irregular polygonal or rounded, overlapping. The primary plates are distinct, also a marginal plate; the radial shields are somewhat more elongated, though mainly of the same shape as in other specimens. Mouth papille almost equally large, only the innermost one on each side pointed. The innermost ventral plates not quite so broadly in contact, nor always so many of them in contact. Besides these no differences of importance are found. The numerous specimens vary rather widely, especially in the cover- ing of the disk. There are large specimens with the disk scales perfectly smooth, and there are small specimens with thick swollen scales. The radial shields sometimes only just meet at their outer end. The ventral plates sometimes are separated from the fourth joint in large specimens. The arm-spines are often a little longer on the joints in the disk than on those farther out. One specimen (Station 3432) has the arm-spines more developed than usual. Stations 3360, 1672 f.; 3362, 1175 f£.; 3366, 1067 f.; 3375, 1201 f£,; 3376, 1182 f.; 3381, 1772 f.; 3392, 1270 £.; 3398, 1573 £.; 3399, 1740 £; 3400, 1322 f.; 34138, 1360 f.; 8414, 2232 f.; 3432, 1421 f. The description of this species somewhat recalls that of O. grandis Verrill (119); but as that species has not been figured it is impossible to say anything more definite about their possible relations. 14. Ophioglypha plana n. sp. Plate III, Figs. 1-4. Diameter of disk, 12 mm.; width of arm close to disk 2 mm.; length of arms, c.60 mm. Five to six short mouth papille to each side, the outer- THE OPHIURIDZ. 123 most square, the innermost pointed; one a little larger on the apex of jaw. Mouth shield with an angle within, outer edge almost straight, outer corners rounded; the lateral sides are a little restricted by the genital slits; equally broad and long. Side mouth shields long and narrow, meeting within. First ventral plate polygonal, as large as the following. Second to fourth (third) with inner end truncated, those farther out with an angle within; from the fifth (fourth) they are widely separated. Outer edge of the first three ventral plates much rounded, then it gradually becomes almost straight. Outer laterals straight (along the tentacle pores), inner laterals re-enteringly curved. Side arm-plates long and almost straight, meeting broadly below from the fourth joint, above from the fifth to sixth joint. Dorsal plates with outer edge much rounded, inner end truncated on the first 5-6 joints; from here they have an acute angle within, and are sepa- rated by the side arm-plates ; the lateral sides are straight. The disk is covered with coarser or finer overlapping scales, among which the primary plates are rather conspicuous, especially because they are of a darker color than the other scales; the network of the chalk sub- stance is coarser than in the other-scales. Radial shields not very large, separated within by one or more scales, meeting more or less broadly with- out, the one overlapping the other. Sometimes they are wholly separated (Fig. 2). Outer edge of the radial shields rather straight, there being almost no incisure at all in the disk at the base of the arm. In the inter- brachial spaces there is usually an inconspicuous marginal plate. Ventral side of the disk covered with similar overlapping scales, among which none are conspicuous. Genital plate narrow, becoming a little broader as it passes to the dorsal side of the arm, where it bears the arm-comb, whose two parts almost or wholly meet in the median line over the arm-basis. The papillee are rather short, more or less pointed, 6-9 to be seen from above. There is no secondary arm-comb. Papille along the genital slits small, close set, rounded. The dorsal side of the disk flat, the margin not rounding towards the ventral side, whereas the ventral side bends towards the dorsal side. There is, however, no sharp edge. Three rather well developed arm-spines, the upper one the longest, the lowest one the shortest; especially on the first free arm-joints the upper- most spine is long, almost as long as the next joint; they are not quite equally spaced, the uppermost being a little apart from the other two. The tentacle pores are distinct in the greater part of the arm; the first pore ——- as 124 THE OPHIURID&. does not open into the mouth space. Tentacle scales: first pair of pores with 6-7 on inner, 8-9 on outer side; second with 5-6 on inner, 6-7 on outer side; and thus the number gradually diminishes ; from the eighth pore none on the inner side, from about the twelfth only one on the outer side. At the distal end of the tentacle pore there is a small but distinct supple- mentary plate, which connects the outer corner of the ventral plate with the outer edge of the side arm-plate, as in O. twmulosa. At the first pore this plate is also to be seen, but here it lies proximally to the first ventral plate. Color in alcohol: gray. The numerous specimens differ very little from the one described. The number of tentacle scales is somewhat variable. One specimen had, at the first pore 3-4 on inner, 5-6 on outer side; at the second, only 2 on inner, 4 on outer side; from the seventh there was only one on the outer, side. The mouth shield is sometimes almost without restriction on the lateral sides, and it then is almost the same as that in O. tumulosa. As a whole, these two species are very nearly related, but there is no great difficulty in distinguishing them: the incisure in the disk (including 2-3 rudimentary dorsal plates in O. tumulosa, almost wanting in O. plana, specimens of the same size being compared), the arm-comb (almost invisible from above in O. tumulosa, well developed, often continuous over the base of the arm in O. plana), the dorsal plates (in mutual contact until about the 20th joint in O. tumulosa, only to the 7th-9th joint in O. plana), giving sufficient char- acters. Of the specimens of O. plana none exceed the size of 15 mm. in diameter of disk, whereas O. twmulosa grows much larger. In very small specimens (diameter of disk 4-5 mm.) the ventral and dorsal plates are separated from the second or third. A few small speci- mens had the inner angle of the mouth shield more acute than common. The upper arm-spine not always distinctly longer than the others in these small specimens. Stations 3357, 782 f.; 3360, 1672 f.; 3361, 1471 f.; 3374, 1828 f£.; 3376, 1132 1.; 3381, 1772 f.; 5392, 1270 f.; 3398, 1573 f.; 3399, 1740 £.; 3400, 1822 f.; 3413, 1360 f.; 3414, 2232 f. iC en a WR a t i i THE OPHIURIDZ. 125 15. Ophioglypha scutellata n. sp. Plate Il. Figs. 4-6. Diameter of disk, 9 mm.; width of arm close to disk, 1.5 mm.: length of arms unknown. ‘Three to four mouth papilla on each side; the two (three) outer ones are short, square, and close set, the innermost one and that on the apex of jaw pointed. Mouth shield almost hourglass-shaped, with an angle within and outer edge curved, the lateral sides deeply constricted ; longer than broad. Side mouth shields long and narrow, a little narrower without than within, where they meet. Ventral plates broader than long, all widely separated. First ventral plate rhomboidal, smaller than those beyond; second with inner edge curved, outer edge a little concave; the rest have a short peak within and a median cut in the outer edge; they become gradually shorter, almost rectangular, the short sides of the rectangle made by the outer laterals, the inner laterals standing almost at a right angle to the longitudinal axis of the arm, re-enter- ingly curved. The first two ventral plates are separated by a small rec- tangular plate, which also separates the side arm-plates of the first joint (this plate is not developed on all the arms, but there is then a rectangular naked space on the same place). Between the second and third ventral plate there is a triangular or rectangular naked space, which separates the side arm-plates of the second joint. Also at the inner end of the fourth ventral plate there may be a little naked space. Under side of the arm (inner part) somewhat hollowed. Side arm-plates meeting below from the third arm-joint, above from the fourth or fifth; their outer edge rather prominent. Dorsal plates all with outer edge rounded and lateral sides a little re-enteringly curved. The first is rudimentary, enclosed in the very small incisure of the disk; second to fourth have inner end truncated, from the fourth they are triangular with an acute angle within. Third and fourth are much longer than broad, and by a transverse line divided in two pieces, of which the inner is rectangular, the outer of the same shape as the second dorsal plate. Disk covered with rather delicate overlapping scales, among which the primary plates are not very conspicuous. Radial shields not very large, meeting broadly without, separated within by some few scales. Inter- brachial space with a rather large, semilunar marginal plate (not distinct 5 126 THE OPHIURIDA. in the figure). Under side of the disk covered with small scales only. The edge of the disk sharp, both sides rounding equally towards it. Genital scales narrow, in two pieces. Papilla along the genital slits very small, close set, rounded; they become somewhat larger as they pass to the dorsal side of the arm to form the arm-comb; only about five papilla to be seen from above; they are not pointed. There is no secondary arm-comb. Four to five short, close set arm-spines, growing gradually longer from above downwards; they are nearer to the ventral than to the dorsal side. First tentacle pore opening into the mouth space; the next pores rapidly diminishing in size, distinct to the 8th-9th joint. Tentacle scales: first pore has 4—5 on each side; second, three on inner, two on outer side; third, two on inner, one on outer side; fourth, one or none on inner, one on outer side; and from the fifth there is only one on the outer side. Color in alcohol: gray. One specimen from Station 3425, 680 f. 16. Ophioglypha nana un. sp. Plate Il. Figs. 10-12. Diameter of disk, 6 mm.; width of arms close to disk, 1 mm.; length of arms unknown. Five short, square, close set mouth papills on each side, and one diamond-shaped at the apex of jaw; the two outer ones broader than the others. (It may be incorrect to name the outermost one a mouth papilla; it reaches from the first ventral plate to the inner end of the first tentacle pore. In other species of Ophioglypha that piece is evidently not a mouth papilla like the rest of them, but here it seems to be so.) Mouth shield pentagonal, an angle within, outer edge with a little peak in the median line; the corners rounded; equally broad and long. Side mouth shields rather short, narrow, of nearly equal width, meeting within. First ventral plate with inner edge rounded and an obtuse angle without. Those beyond are triangular, with a little median peak on the outer edge, the lateral sides are a little re-enteringly curved; on the second to fourth that is not distinct on account of the tentacle pores, They are equally long and broad. Side arm-plates a little rounded, meeting broadly below from the first, above from the second or third joint. Dorsal plates triangular, all sides a little curved. The first three are of different shape; the innermost is quite rudimentary, separating the two parts of the arm-comb; its outer a Mw THE OPHIURIDZ. 127 edge is concave; the two next have inner end truncated, outer edge curved ; they are not separated by the side arm-plates. There is almost no incisure in the disk at the base of the arms Disk covered with rather coarse, overlapping scales, among which the primary plates are not conspicuous. The central plate is five-sided, with a little scale at each corner. Radial shields rather short, not very conspicu- ous, meeting broadly without, separated within by one or two scales ; they do not meet in the median line, but the right radial shield overlaps the left. In the interbrachial space there is a rather large marginal plate, which connects the radial shields of each two adjoining arms. Under side of the disk covered with a few rather large scales. The edge of the disk is sharp. Genital scale rather broad; the papilla along the genital slits very small and indistinct, rounded; they become somewhat larger as they pass to the dorsal side of the arm to form the arm-comb; only three or four papillee to be seen from above; there is no secondary arm-comb. The genital slits begin at the first ventral plate, the papille only at the end of the mouth shield ; along the inner part of the slit there is a long, narrow scale, adjoining the side edge of the mouth shield. Three short arm-spines, the upper one a little apart, from the other two. First tentacle pore not opening into the mouth space; on the second to fourth joint they rapidly diminish in size; beyond the fourth there are no pores at all. Tentacle scales: first pore has 4 on outer, 3-4 on inner side ; second, 1-3 on outer, 2-3 on inner side; third, 1-2 on both sides; fourth, 1-2 on outer, none or a very small one on the inner side. On the next joints a little rudimentary tentacle scale sometimes may be found. Color in alcohol: gray. One specimen from Station 3364, 902 f. 17. Ophioglypha divisa n. sp. Plate IV. Figs, 10-12. Plate V. Figs. 1, 2 Diameter of disk, 11 mm.; width of arm close to disk, 2 mm.; length of arms unknown, but presumably about 3-4 times the diameter of the disk. Mouth papilla 5-6 on each side, short, square, making a close line; the outermost ones a little broader than the others; one diamond-shaped at the apex of jaw, scarcely longer than those at the sides. Mouth shield very curious; divided by a median line, which bifurcates at the outer 128 THE OPHIURIDZ. end; it thus consists of one small median and two large lateral pieces. (Plate IV. Fig. 10.) Other specimens have the mouth shield divided into two pieces only by a median line. (Plate V. Fig. 1.) Side mouth shields rather short and broad, meeting within. The whole mouth angle is some- what hollowed. First ventral plate with inner edge rounded, outer edge forming a very obtuse angle. The other ventral plates triangular, with the sides a little curved; the second to fourth have their lateral sides inconsiderably re- stricted by the tentacle pores. They are equally long and broad, all widely separated. The side arm-plates have the outer edge a little prominent ; they meet above from the fourth or fifth joint. The dorsal plates are divided in two pieces by a longitudinal line, which is rather irregular ; sometimes it is almost straight, median; sometimes it is wholly wanting on a few joints, the dorsal plates there being thus undivided. They are triangular, the first three or four, which are in mutual contact, with inner end truncated; outer edge rounded; they are equally long and broad. The disk is covered with rather coarse, not overlapping scales, among which the primary plates are distinct; round the scales there are some indistinct ridges. The radial shields not very large, somewhat irregular, separated by a single row of scales, sometimes just meeting without. Incisures of the disk at the base of the arms very inconsiderable, enclosing one rudimentary dorsal plate; interbrachial spaces with a distinct marginal plate. The ventral side of the disk almost wholly covered by a large plate — outside the mouth shield, sometimes divided by a median line (Plate V. Fig. 1), and by the large genital plates; only a few small scales are seen along the margin. The edge of the disk not sharp, both sides being rounded towards the margin. Papille along the genital slits close set, square, rather indis- tinct; arm-comb little developed, only four papille to be seen from above ; they are small and rounded. The genital scales sometimes do not reach the dorsal side of the arm, the papille then are inserted on the outer edge of the radial shields. No secondary arm-comb. Four short arm-spines, three close together below, of which the middle one is the longest, and one being apart at the upper side of the arm. Only four tentacle pores, very small, except the first, which does not open into the mouth space. Tentacle scales: first pore three on outer, two on inner side; second and third, two on outer, one on inner side; fourth, two on outer, none on inner side. | ye THE OPHIURIDZ. 129 Color in alcohol: gray. Five specimens from Stations 3411, 1189 f.; 3413, 360 f. This species stands very near to Ophioglypha inornata Lym., the only dif- ference of any importance, as far as we are able to see, being that the dorsal plates are here not divided by a longitudinal median line. In every other respect the two species seem to be quite alike. Lyman does not mention that the mouth shield in O. inornata is divided by a longitudinal median line, but the figure shows that line very clearly. 0. inornata was taken in the Atlantic in 1° 47’ Lat. N., 24° 26’ Long. W. (1850 f.). On Station 3400 was taken a young Ophiuran (diameter of disk 4 mm.), which we must regard as the young of 0. divisa, though it differs somewhat from the above described larger specimens. Four of the mouth shields are undivided, but the fifth is divided as on Plate IV. Fig. 10;* but especially the covering of the dorsal side of the disk is different, the six primary plates being very large, polygonal, taking up by far the most space. At the margin of the disk are seen the short, broad, polygonal, not separated radial shields and two smaller plates in each interbrachial space. No genital papillae or arm-comb yet developed. The dorsal plates as yet only partly divided by a median line, but on some few of them this line is distinct. There are only one or two arm-spines below and one at the upper side of the arm. Mouth papille and tentacle scales as on the larger specimens; nor do the ventral plates show any noteworthy difference. (Plate V. Fig. 2.) The eight species here described included, there are now known no less then eighty-seven species of the genus Ophioglypha. Hvidently the genus needs to be subdivided; but it seems impossible to do so without having specimens, or at least good figures, of all the species. Meantime very much is still wanting in this respect, several of the species having never been figured. Some species, however, show more or less important charac- ters in common, and such will possibly form definite groups or subgenera. Lyman established three groups with the types 0. ciliata Retz, O. bullata Wyv. Thoms., and O. nodosa Ltk., but for many species he did not find any common character of importance. Lupwic (72) proposes to make a sepa- rate genus of those species which have no arm-comb, Ophioglyphina. We do not believe this character to be of so great value, as these species are * Sometimes also an undivided mouth shield may be found in larger specimens. 130 THE OPHIURIDZ. evidently not all closely related. Thus, O. aurantiaca Verr. and O. inermis Lym. are not very, nearly related to O. deshayesi Lym. and O. abyssorum Lym. ; again O. maculata Ludw. belongs to the group of O. ciliata and has no close relation to any of those named above. 0. fraterna Lym. and 0. sau- rura Verr. have no arm-comb either; but as these species are not figured, it is almost impossible to say anything with certainty about their relations. A character, which may be of importance, is to be derived from the tentacle pores: whether they continue far out on the arms, or are only found on the first four—five joints, as in our O. nana and O. divisa, and without doubt in several of the species figured by Lyman. The most important char- acter however seems to be the form of the ventral plates. In Lyman’s first group (type O. ciliata Retz.) the ventral plates are short, all widely separated, much wider than long beyond the second plate ; in his second and third group the ventral plates of the inner part of the arm are as broad as long, almost hexagonal, in contact in their whole breadth. These two groups are dis- tinguished from each other by the length of the arms: in the second group (type O. nodosa Ltk.) only twice the diameter of the disk; in the third (type O. bullata Wyv. Thoms.) much longer, about 4-5 times the diameter of the disk. To the latter group belongs our O. superba. Some of the species, however, which Lyman refers to this group, do not appear really to belong to it, e.g. O. ornata Lym, and O. radiata Lym. These would per- haps better form another group with 0. radiata Lym. as type, characterized by the axe-shaped ventral plates. To this group would belong our O. adcisa and perhaps O. obtecta. Another group apparently would be formed of the species with ventral plates, as in our O. twmulosa and O. plana. Finally, the specimens with all the ventral plates widely separated, which do not belong to the first group, would perhaps form one or two special groups. Evidently a natural subdivision of the genus Ophioglypha would not be very difficult to work out, but it will be necessary to have ample material for comparison. Ophioglypha Forbesi Duncan is said by Korner (128) to form an inter- mediate type between the genera Ophioglypha and Ophiomusium. That surely is not correct. The most important character which distinguishes Ophiomusium {from Ophioglypha is found in the first pair of tentacle pores (in reality the second pair). In Ophioglypha these pores are very large and conspicuous, in Ophiomusium they are not at all seen from without, but lie totally in the mouth space. (This character however was not mentioned by Lyman.) Only Ophiomusium flabellum Lym. and O. pulchellum Wyv. Thoms. THE OPHIURIDE. 131 make an exception ; but they ought not to be referred to the genus Ophiomu- sium, they would better make a separate genus. The other characters of Ophiomusium, closely soldered disk-plates, few tentacle pores, etc., may also be found in Ophioglypha species. Ophioglypha Forbesi evidently is a typical Ophioglypha species. 18. Ophiocten pacificum 2. sp. Plate III. Figs. 5-7. Diameter of disk, 12 mm. ; width of arm close to disk, 2.6 mm.; length of arms, 5 to 6 times the diameter of the disk. Four short, close set mouth papille on each side of mouth angle; the two outer ones are broad, espe- cially the outermost; the two inner ones and that on the apex more acute, though not spiniform. Mouth shield somewhat broader than long, with outer edge a little curved, outer corners rounded, lateral sides straight; an obtuse angle within. Side mouth shields a little broader within than with- out, not always meeting within. Ventral plates all widely separated; the first one four-sided, larger than the following, with outer edge slightly curved, lateral sides almost straight, inner end truncated. The other ventral plates have their outer edge strongly curved and an angle within; this angle or peak becomes afterward less prominent farther out on the arm, and the ventral plates thus have their inner side almost straight, with only a little peak in the median line.* The side arm-plates meet broadly below in the whole length of the arm; the sides are slightly curved. The dorsal plates are four-sided, roof-shaped, broader than long; the outer edge is broader than the inner, both are slightly curved, the outer convex, the inner concave, the lateral sides straight. They cover almost the whole dorsal side of the arm, the side arm-plates thus being very broadly separated above. At the base of the arm the sides are partly naked, and both the dorsal and the side plates are somewhat smaller than farther out. Disk covered with small, irregular, somewhat swollen scales, among which the primary plates are rather inconspicuous. Radial shields small, triangular, separated by numerous small scales. Ventral side of the disk covered with numerous small, overlapping, not swollen scales; edge of the disk sharp, as common in Ophiocten. Genital scale not distinct. Some * Figure 5 gives the ventral plates a little too short, and their outer edge should be a little more curved. 132 THE OPHIURIDZ. very delicate spines along the outer part of the genital slits (not seen in the figure). Arm-comb consisting of only a few spines on each side, along the outer edge of the radial shields, not continuous over the arm-basis. There are also some few (4-6) papilla along outer edge of first dorsal plate. Three arm-spines, close together, sharp, slender, tapering; the upper one on the first 5-6 free joints somewhat longer than one joint, sometimes as long as two joints, farther out scarcely as long as one joint ; the two other spines shorter, the lowest one the shortest. First tentacle pore, as common in this genus, not opening into the mouth space. For the other pores it is to be remarked that they do not touch the ventral plates, but lie wholly in the side plates, near the side of the arm. (This is also the case in O. sert- ceum Forb., though not so evident as here.) Tentacle scales: first pore with one on outer side, two, seldom three, on inner side ; the rest all with one conspicuous scale on the outer side, next the lowest arm-spine. On the second to fifth or sixth there is also seen a little scale at the distal end of the pore. Color in alcohol: gray. Stations 3363, 978 f.; 3365, 1010 f.; 3371, 770 f.; 3375, 1201 f.; 3376, 1132 f.; 3380, 899 f.; 3392, 1270 £.; 3393, 1020 f.; 3398, 1073 f. ; 3400, 1322 f. Most of the specimens rather badly preserved. ‘There are sometimes five mouth papilla on each side, and they may be a little more pointed than in the figure, though never spiniform. Besides that there are no variations worth mentioning. 19. Ophiomusium glabrum 2. sp Plate IV. Figs. 7-9. Diameter of disk, 32 mm.; width of arms close to disk, 6 mm.; length of arms, 5-6 times the diameter of disk. Seven to eight close set square mouth papillae on each side, and one diamond-shaped at apex of jaw; the two-three outer ones a little longer than the rest. Mouth shield small, trian- gular, mostly restricted at the outer corners, with an acute angle within and outer edge straight; a little longer than broad. Side mouth shields long, broader without than within, where they meet. First ventral plate transversely elongated (in other specimens it is not so THE OPHIURIDZ. 133 broad, more hexagonal). The following plates are about equally broad and long, all with an angle within and outer edge curved. Second to fourth have outer laterals re-enteringly curved on account of the tentacle pores ; from the sixth they are triangular, with all the sides a little curved. They continue almost to the end of the arm, sometimes only to about the 30th joint ; they are all widely separated by the side arm-plates ; in some of the larger specimens, however, the second to fifth may be in contact, the inner end of these plates being then truncated. First and second ventral plates are very seldom in contact. Side arm-plates somewhat rounded, outer edge a little prominent ; they meet above from about the sixth (free) joint. The dorsal plates are as long as broad, almost rhomboidal on the inner joints, with an angle within and without; farther out they become more elon- gated, with an acute angle within and an obtuse angle without. They are distinct almost to the end of the arm. The second dorsal plate has its inner angle truncated; in some specimens that is the case with others of the inner dorsal plates. The first is crescent-shaped, broader than long; inside this there are 3-4 short, broad, irregular, rudimentary dorsal plates. Disk covered with small, usually angular scales, among which the pri- mary plates are hardly distinguishable. Radial shields very large, widely separated by several irregularly placed scales. One rather large, semi- lunar marginal plate in the interbrachial space. Ventral side of the disk covered with similar polygonal scales, among which are sometimes seen some small spines or grains. Towards the margin there are some few larger scales. Edge of the disk rather sharp, the dorsal side not rounding towards the ventral side. Genital scale narrow, but usually distinct in the whole length. Genital slits reaching only the third joint, with a double row of close set, square papillz, one on the genital scale, the other along the side arm-plates. Outside the genital slits the genital scale widens and bends a little away from the arm; for which reason the third and fourth arm-joint appear somewhat wider than the other arm-joints. (Not always so distinct as in Figure 7.) Seven to eleven short, delicate arm-spines, equally spaced. Only the lowest one is sometimes thicker and longer than the rest. Four pairs of large tentacle pores; some specimens have five pairs; not seldom only one of the pores of the last pair is developed. One rather large tentacle scale on the outer side, and one or two on the inner side. Color in alcohol: gray. 6 134 THE OPHIURID. Numerous specimens from Stations 3362, 1175 f.; 3363, 978 f.; 3366, 1067 £.; 3374, 1823 f.; 3376, 1132 £.; 3381, 1772 f.; 3382, 1793f.; 3392, 1270 £.; 3399, 1740 f.; 3400, 1822 f.; 3414, 2232 f.; 3431, 995 f. Younger specimens differ in having the radial shields separated by only a single row of scales; the primary plates are distinct. The genital slits only reach to the second joint, and there are only 4-6 arm-spines. The larger specimens do not vary to any great extent. The mouth shield sometimes is divided by a transverse line, and also in general outline it is rather variable. The arm-spines sometimes are shorter and thicker. Some- times there are a few small spines along the margin of the disk. There is a rather thick skin over the disk scales, which are not hidden by it, the skin being translucent. 20. Ophiomusium Diomedee ». sp. Plate IV. Figs. 1-3. Diameter of disk, 13 mm.; width of arm close to disk, 2.6 mm.; length of arms unknown. 7-8 mouth papilla to each side: the three outermost ones are rather long, closely soldered together, somewhat rounded ; the four-five innermost ones are shorter, more pointed, and not close set; one pointed on apex of jaw. Mouth shield small, spearhead-shaped, with outer edge straight; a little longer than broad. Side mouth shields with outer end broad, inner end somewhat narrower ; meeting within. First ventral plate very small, polygonal. All ventral plates with outer edge straight; the three-four first are in mutual contact, the second and third having their inner end truncated ; second to fourth have the lateral edges rather deeply constricted by the tentacle pores; from the fifth they are triangular, widely separated ; they continue to the end of the arm (as far as can be judged, all the arms being broken). Side arm-plates with outer edge rather prominent, thick, rounded ; meeting below from the fourth, above from the second joint. Dorsal plates triangular, their outer edge almost straight, only with a little peak in the median line; the first dorsal plate has inner end truncated. At the arm-basis there are some rudimen- tary, irregular polygonal dorsal plates, and at the sides (outside the radial shields) there are, corresponding to these dorsal plates, some plates, which look like rudimentary side arm-plates, but are not so really. Arms flat above and below. THE OPHIURIDZ. 135 Disk covered with distinct, rather thick, smooth, polygonal scales, among which the primary plates are not to be seen, except the pentagonal central plate. Radial shields not quite so long as half the radius of the disk, twice as long as broad. They are widely separated by a single row of scales. In the interbrachial spaces there is a conspicuous marginal plate, separated from the radial shields only by some very narrow scales. Under side of the disk covered by similar polygonal plates. The edge of the disk not sharp, both sides rounding towards each other. Genital scales distinct, but not very wide; genital slit reaching to the margin of the disk ; its inner end, at the outer end of the mouth shield, is somewhat widened ; here is seen a little triangular opening. Papille along the genital slits distinct, close set, rounded. They do not extend to the dorsal side of the arm, there being no arm-comb. Five (four-six) short, equal arm-spines, the two or three lowest a little closer together than the others. Only the first three joints with tentacle pores, each pore with one large oval tentacle scale at the outer side. Color in alcohol: gray. 1 specimen from Station 3404, 386 f. From the same station there is another specimen (diameter of disk 5 mm.), which differs from that described, the disk scales being somewhat granu- lated, and the radial shields not being quite separated. There are four arm- spines; the ventral plates are separated from the third. Evidently it is a younger stage of the same species. 21. Ophiomusium variabile n. sp. Plate IV. Figs. 4-6. Diameter of disk, 14 mm.; width of arms close to disk, 2.5 mm.; length of arms, c. 5 times the diameter of the disk. Seven close set square mouth papillee on each side, one longer, pointed at apex of jaw; the three outer ones are much broader and larger than the inner ones. Mouth shield a little longer than broad, of a curious form; an ‘acute angle within, then widening, with the sides rounded; the outer part very restricted ; the whole looks like a leaf with its stalk. Side mouth shields long, their inner end very narrow, restricted by the mouth shield, just meeting within or sepa- rated; their outer end is very broad. 136 THE OPHIURIDZ. First ventral plate very small, triangular, somewhat elongated. The three next with the lateral sides a little restricted by the tentacle pores. The outer edge of the second (and sometimes of the third also) a little re- enteringly curved; the other ventral plates have the outer edge gently curved. From the fifth they are triangular; they continue far out on the arm, but are not distinct quite to the end. They are all about equally long and broad, widely separated by the side arm-plates, which also meet broadly above from the second (free) joint. Outer edge of the side arm-plates not prominent, the sides straight. The dorsal plates have an acute angle within and outer edge very strongly produced, rounded; a little longer than broad. They continue to the end of the arm. At the base of the arm there are four rudimentary dorsal plates, the inner one triangular, with angle inwards (between outer ends of the radial shields), the two next four-sided, much broader than long, the fourth five-sided, with an angle without. At the base of the arms, on each side of the rudimentary dorsal plates there is a more or less developed granular covering, sometimes only some few grains. The arms are very thin and flexible in their outer part. Disk covered with numerous rather delicate, small, smooth, angular (or rounded) plates, among which the primary plates are usually not to be seen. The radial shields are large and conspicuous, their outer ends more or less broadly in contact, their inner ends separated by some few elongated scales. Their form is rather curious, the outer edge being bent strongly inwards and very long; the margin of the disk therefore bends inwards between the arms. In the interbrachial spaces there is a rather large semilunar marginal plate, separated from the radial shields by a little crescent-shaped plate on each side. Under side of the disk also covered by small, polygonal plates, somewhat larger than those on the dorsal side. The genital scales not dis- tinct; the genital papille quite rudimentary ; there are some a little more distinct papillx at the adradial side of the genital slit along the side arm- plates. The genital slit reaches the margin of the disk. The edge of the disk is rather sharp. Two or three short arm-spines, close together at the under side of the arm; the inner five or six free joints mostly bear only two spines; beyond them there are three. Three pairs of small round tentacle pores, each with one rounded. tenta- cle scale at the outer side. Color in alcohol: dark gray. THE OPHIURIDZ. 1357 Six specimens from Station 3417, 493 f. One specimen from Station 3426, 146 f., differs from the other specimens, its disk covering being thicker than common in this species. The form of the mouth shields is very variable, the inner part being very different in breadth ; sometimes it is not broader than the outer part, some- times there is a little peak within, sometimes it is broadly rounded; on the same specimen scarcely two are alike. The radial shields not seldom are wholly separated. These two species very much resemble O. familiare Koehler, and O. elegans Koehler, from the Indian Ocean (67); O. Diomedew the former, O. variabile the latter. They are, however, sufficiently characterized, O. Diomedew by its inner ventral plates being in mutual contact, O. variabile by its curious radial shields. 22. Ophiomusium Lymani Wyv. Thomson. Plate III, Figs. 8-11. Wryv. Tuomson: Depths of the Sea, p. 172, Figs. 32, 33. Tu. Lyman, Challenger, Vol. V., Ophiuroidea, p. 90. ie “ (76), p. 245, Plate V. Figs, 55-57. As there is not yet given either a full description or detailed figures of this species, it is given here. Diameter of disk, 30 mm.;, width of arm close to disk, 5 mm.; length of arms, 4—5 times the diameter of the disk. Six to seven short, square mouth papilla on each side, making a close line, and one diamond-shaped (often irregular) at apex of jaw. The outer papilla is somewhat broader than the rest. Mouth shield often irregular, divided in smaller pieces (Fig. 8) ; its appropriate form, however, is that seen in Figure 9: an acute angle within, outer edge straight, lateral sides deeply restricted, the inner part of the shield being much narrower than the outer; it is somewhat longer than broad. Side mouth shields large, meeting within, the outer end much broader than the inner end. First ventral plate of a peculiar form: inner edge concave, the corners produced along the sides of the mouth slit; lateral sides straight and outer edge slightly concave, with a little peak in the median line. The two next ventral plates small, pentagonal, with an angle within and outer edge as on the first plate ; lateral sides with a restriction on the middle part for the 138 THE OPHIURIDZ. tentacle pores. They are just in contact. No ventral plates beyond the third. Side arm-plates from the third joint closely soldered together in their whole length; on the dorsal side they are broadly in contact from the first joint. Their sides almost straight; the outer edge makes a fine curve (convex inwards) across the under side of the arm; on the sides of the arm it is rather prominent. Dorsal plates very small, triangular, with outer edge strongly rounded. They continue almost to the end of the arm. At the arm basis, outside and between the outer ends of the radial shields, there are some small, irregular plates, whereof the median row must be regarded as rudimentany dorsal plates. Disk covered with small but distinct, irregular, polygonal scales, among which the primary plates are not distinct except the central plate. Radial shields very large, more than half the radius of the disk, separated by a single row of scales, two of which are rather large; between their inner ends are some more irregularly placed scales. Each interbrachial space is occupied by a double row of scales and by a large marginal plate, which connects the radial shields of each two adjoining arms. Under side of the disk covered by several small and large, irregular polygonal flat scales, among which one outside the mouth shield is most conspicuous; usually it joins the outer edge of the mouth shield. Genital scale rather large, end- ing at the third arm joint. Genital slits very narrow, reaching only to the second, in some specimens to the third joint; the inner end is curved. No genital papille. Under side of disk and arms quite flat; the dorsal side is rounded towards the ventral side; the edge of the disk, which is not sharp, is thus at the level of the ventral side. Six to eight small, rudimentary arm-spines; the second from below is a little larger and almost covers the first. On the outer part of the arm the spines have the form of hooklets. Only two pairs of tentacle pores, the first with one or two oval tentacle scales at the outer side, the second with one. The whole dorsal side of the disk and the side arm-plates above and on the sides of the arm beset with a close granulation, which is most developed on the radial shields, the marginal plate, and the side arm-plates. The granule on the other scales of the disk are much smaller and inconspicuous. The edges of the radial shields are smooth; the side arm-plates have the granulx only along the upper and outer edge. The whole underside is perfectly smooth ; only on the large plate outside the mouth shield there may be a single tubercle. Color in alcohol: gray. * THE OPHIURIDZ. 139 Other full grown specimens differ very little from that described. The granulation is not always so richly developed, especially the side arm-plates may be perfectly smooth. The shape of the mouth shield and the adjoining plate is rather variable. Sometimes there is only a single row of scales in the interbrachial spaces on the dorsal side. In very young specimens (diameter of disk 4-5 mm.) the granulation is not yet developed; the first ventral plate is pentagonal with an angle in- wards, and all the ventral plates are widely separated ; only 3-4 arm-spines. The mouth shield is pentagonal, not longer than broad ; the large plate out- side the mouth shield occupies, together with the large genital scales, almost the whole under side of the disk, only a pair of small plates being seen at the margin. On the dorsal side of the disk the six primary plates are very conspicuous, thick and high, as large as the radial shields, which are in mutual contact only at the outer end, separated within by a small scale ; among the primary plates are also seen some small scales.. The inter- brachial space is covered by a large marginal plate and a smaller one inside that. Only one of the rudimentary dorsal plates yet developed. (Lyman, 76, Figs. 55-57.) Numerous specimens from Stations 3362, 1175 1.; 8363, 978 f.; 3364, 002 fs 8871; 770 i 3376, 4182 f.,..9992, 1270 fs 8398, 1020 25 S407, 885 f.; 3411, 1189 f.; 3431, 995 f., 34382, 1421 f Lyman (Challenger) records this species from the Pacific (88° 2’ W., 38° 6’ S.), but he has only seen an arm of it. Evidently it is very common in this ocean, as well as in the Atlantic. The 24 species of Ophiomusium now known are easily subdivided into two groups: those which have ventral plates in most of the length of the arm, and those which have ventral plates only on the 3-5 first joints. The former group, again, seems to need to be divided into those in which the genital slits do not reach the margin of the disk, and those with very large genital slits, reaching the margin of the disk. To the latter group belong O. familiare Koehler, O. elegans Koehler, our 0. Diomedew and 0. variabile, and (perhaps) O. laqueatum Lym. The two species O. flabellum Lym. and 0. pulchellum Wyv. Thoms. ought not to be reckoned as Ophio- musium, as they differ from all the other specics in having pores at the sides of the first ventral plate. As said above under Ophioglypha, it must be maintained as one of the most important characters of the genus Ophio- musium that there are no tentacle pores visible to the first ventral plate. 140 THE OPHIURIDZ. 23. Ophiactis Savignyi (M. & Tr.). Lyman: Challenger, Vol. V., Ophiuroidea, p. 115. One specimen from Acapulco. 24. Ophiactis profundi ». sp. Plate VI. Figs. 4-6. Diameter of disk, 6 mm.; width of arm close to disk, 1 mm.; length of arms, ce. 5 times the diameter of the disk. One very large, axe-shaped mouth papilla on each side ; the one at the apex below the teeth triangular, with a more or less distinct peak within. The lower teeth more or less ser- rate, the upper ones rounded. Mouth shield about as broad as long, almost rhomboidal, an angle within and without; the sides more or less re-enteringly curved, the outer sides most so; all the angles rounded. It is somewhat hollowed in the middle. Side mouth shields with outer end much wider than inner end, where they meet. First ventral plate very small, its outer end much narrower than the inner end; laterals and inner edge slightly concave. The following ventral plates a little wider than long, in mutual contact almost to the end of the arm, where they become more elongated. Sometimes, however, they are separated by alittle naked space on the inner joints. They are polygonal, inner end truncated (or with an angle), outer side limited by three rather straight lines, which make two obtuse angles; the middle part of the outer side is usually a little concave ; sometimes the whole outer edge is curved ; inner and outer laterals re-enteringly curved; they are a little hollowed in the middle. Side arm-plates with spine ridge rather prominent, meeting above from about the 5th joint. Dorsal plates very broad, twice as broad as long, usually all separated; however, the side arm-plates do not meet on the inner joints, there being a little naked space which separates them. The dorsal plates have outer edge rounded, a very obtuse angle within, and lateral sides slightly rounded. Arms rather flat, not wider outside the disk. There are constantly six arms. Disk covered by small, smooth, rather thick, overlapping scales, among which the primary plates are not distinct. No spines on the disk. The radial shields about as long as half the radius of the disk, narrow, with THE OPHIURIDZ. 141 adradial edge straight, abradial edge curved, and outer edge straight; they are separated by a single row of scales; mostly there are no scales along their outer edge. Under side of the disk covered with scales similar to those on the dorsal side. Edge of the disk rather sharp. Three rather stout, smooth arm-spines, the middle one the stoutest ; they are as long as one joint and a half. One large oval tentacle scale. Color in alcohol: pale brown. Stations 3380, 899 f., 6 specimens; 3406, 551 f., 1 specimen. Inside the large mouth papilla there is sometimes seen another papilla, and it thus looks as if there were two mouth papillee on each side ; however, it is not so: this papilla belongs to the first mouth tentacle, and is thus the same as that usually seen in Amphiwra. Some of the specimens have one half of the disk regenerated and the three arms more or less shorter than the rest. This species thus has self-division. Evidently this species is closely related to Ophiactis flecuosa Lym., from which it is separated only by small differences: the form of the mouth shield, of the large mouth papilla(?), of the ventral plates, and of the radial shields; further, O. flexuosa has distinct scales all round the radial shields, whereas O. profundi has no scales outside of them. Finally, O. fleauosa has five arms, whereas O. profundi has six. The latter character evidently is the most important. Onpage 116 of the Challenger Report, Lyman says: “The ten specimens from Station 142, 150 fathoms, may be the young of this species (O. flevuosa). They have six arms, while Ophiactis flexuosa has but five.” That 0. profundi is not the young of O. fleauosa is evident. The largest specimens have a diameter of 6 mm., the specimen of O. flerwosa described by Lyman only 7 mm. Upon the whole, we think there is no sufficient evidence that in any species the young has six arms, the adult only five. We therefore also doubt that Lyman is right in asserting that to be so in O. Miilleri Ltk. We have found nothing in the literature which definitely shows that to be the case. LUTKEN (Additamenta, Vol. II. p. 230) describes an older 5-armed specimen, and then only says: “ Though I presume this form to be a separate species, I will not omit pointing out the possibility that O. Miilleri was only the young of this form.” Lyune- MAN * says, by the description of the var. guinqueradia, that he has not been able to tell definitely whether it was a new species or the adult of O. Miilleri. ‘Lyman himself says (Ill. Catal. Mus. Comp. Zodl., Vol. I. * Ofvers. kgl. Svenska Vetensk. Akad. Férhandl., 1871. ff 142 THE OPHIURIDZ. p- 110): ‘‘As a rule the number [of arms] is six, and of these two or three are almost always smaller than the rest. The arms vary much in number; occasionally a specimen may be seen with only one. A young one had five arms about 3.5 mm. long, the diameter of disk being 1.2 mm.” Beyond that he gives no further evidence as to the point in question, only in the Challenger Report he definitely says it to be so (p.118). On page 116 he says, “The socalled adult of 0. Miileri has five arms.” It thus seems that LyMAN was, however, not wholly convinced that it was so. Also to O. plana Lym. this species will be closely related; but as no figures are given of that species, it is almost impossible to say anything definitely aboutit. From the notice in the Challenger Report, page 116, it seems that O. plana has six arms; in the original description nothing is said of this. ; 25. Ophiactis duplicata (Lym.). Plate VI. Figs. 1-3. Amphiura duplicata Lyman. Til. Catal. Mus. Comp. Zoél., No. VIII., Part II. p.19. Plate V. Fig. 78; outline, Fig. 87. id bid G Challenger Ophiuroidea, p. 136. Plate XVII. Figs. 10-12. (76), p. 251. Rs “« Kornier. (64), p. 74; (127), p. 49. To this species we refer with a little doubt some specimens from Stations 3380, 899 f. (together with O. profundi), and 3407, 885 f. As this species has hitherto been known only from the Atlantic, it is important to be quite sure of the identification; but the figures hitherto given thereof are not quite satisfactory, so we are not wholly convinced of the identity. We therefore give figures of our specimens. The differences found between the Atlantic and the Pacific specimens are rather unimportant. The mouth papillae, mouth and side mouth shields, and the ventral plates, show some small differences, as will be seen by com- paring Lyman’s figures with ours. But, as there is some variation in our specimens in respect to mouth papillae (3-5), mouth shield (sometimes re- stricted at the outer end, not rounded), and first ventral plate (more rounded), there cannot be much stress laid upon that. It is to be remarked that the outer edge of the ventral plates is a little re-enteringly curved from outside the disk; whether that is a real difference or not cannot be seen from Lyman’s figures and description. Outside the radial shields there is a little very narrow scale. Finally, the (five) arms appear to be a little shorter THE OPHIURIDZ. 143 than in Lyman’s specimens, only three times the diameter of the disk. Lyman gives the length of the arms as five times the diameter of the disk. Lyman has referred this species to Amphiura, but in this he is evidently wrong. It must be emphasized that one of the most essential features of Amphiura is that there are ¢wo large mouth papille at the apex of jaw, below the teeth. Ophiurans which have not that character cannot be named Am- phwura. (At the same time it cannot be said that all Ophiurans with that character belong to the genus Amphiura.) Especially the genus Ophiactis can only be distinctly separated from Amphiura through that feature. Opihi- actis has never two mouth papille at the apex,* but only one small one (which may also be considered as the lowest tooth). Some more of Lyman’s species of Amphiura thus evidently are also to be transferred to Ophiactis, — A. canescens Lym. and A. patula Lym. Further, one of the species described by Korner (67), Amphiura partita, evidently should also be transferred to Ophiactis, being closely related to O. duplicata, as it has the same remark- able feature of the divided first ventral plate. Curiously enough another of the species described by Koxrnuzr (67), and referred to Ophiactis, namely, O. Lorioh, evidently is an Amphiura. | 26. Amphiura serpentina n. sp. Plate VIII. Figs. 1-8. Plate IX. Figs. 1-2. Diameter of disk, 9 mm.; width of arm close to disk, without spines, 1.5 mm.; length of arms, 7-8 times the diameter of the disk. Two mouth papilla on each side of the mouth angle, the outer one large, irregular, often with two lobes, sometimes wholly divided in two. Mouth shield a little longer than wide, with inner edge strongly rounded ; its outer part is restricted, stalk-like, outer edge rounded. Side mouth shields separated or scarcely meeting within, much wider without than within. First ventral plate small, six-sided. Those beyond all in mutual contact, with inner end truncated, outer edge straight or slightly concave; outer corners much rounded; outer laterals almost straight, the inner re-enter- ingly curved. They are equally broad and long; at the inner end they have a feeble keel. Side arm-plates with a well marked spine ridge; on the inner part of the arm there is a naked space outside each tentacle pore, * In O. duplicata, however, there are sometimes two mouth papillx at the apex, but never on more than one or two of the jaws. 144 THE OPHIURID. the side plates thus not reaching the foregoing joint; that naked space is distinct also from the dorsal side. The side plates just meet above on the inner joints, then are separated by the dorsal plates, and finally they again meet in the outer part of the arm. Dorsal plates transversely oval, with all sides rounded, scarcely separated on the inner joints, then in con- tact almost to the end of the arm, where they again become separated ; about twice as broad as long. Disk covered by small but distinct overlapping scales, among which no primary plates are seen. The radial shields rather large, almost semi- lunar, pointed within, rounded without, twice as long as broad, their length being equal to half the radius of the disk. They are separated by some few, irregularly arranged, small scales ; sometimes they meet at their outer end. Outside the radial shields is a narrow belt of scales in continuation of those in the interbrachial space. Over the arm-basis there is a rather deep but narrow incisure in the disk. Under side of the disk covered with smaller yet distinct scales. Genital scale distinct only at the inner end of the geni- tal slit. The margin of the disk re-enteringly curved; the edge of the disk not sharp. Three, on the inner joints four, equal tapering arm-spines, a little longer than an arm-joint. Two small tentacle scales, which do not form a right angle with each other. Color in alcohol: gray, with a bluish tint. This species is very variable. Considering the described specimen as the typical form, there can be distinguished no less than three rather con- stant varieties : — Var, a (Plate VIII. Figs. 4, 5) differs from the typical form in the follow- ing respects. The mouth shield has the outer end more restricted, its whole form being somewhat different (in other specimens, however, it has the same shape as in the typical form). The ventral plates have the outer edge strongly rounded, and there is a more distinct keel; they are a little longer than wide. The radial shields are narrower and separated by many small scales, which are disposed in rather regular series. The scales on both sides of the disk (except those around the radial shields) are very small, but high, looking almost like small grains. The tentacle scales are smaller than in the typical form; sometimes there are three. A specimen from Station 3424 has the mouth shields yet wider than in the typical form ; the scales do not resemble grains, are smooth, but as small as in the figured specimen. THE OPHIURIDZ. 145 Var. 6 (Plate VIII. Figs. 6-8) resembles the typical form very closely. The ventral plates have the outer edge more rounded, and there is a more distinct keel; the radial shields are narrower. The most important differ- ence is, however, that it has four, on the inner joints five, arm-spines ; the upper one is the shortest, about as long as half an arm-joint ; they then become gradually longer downwards, the lowest being the longest, a little longer than a joint. The mouth papille are more or less pointed. Var. c (Plate IX. Figs. 1, 2) differs much more from the typical species, and should perhaps be regarded as a separate species, ‘The arms are®c. 15 times as long as the diameter of the disk (6 mm.). The outer mouth papilla is long and pointed ; the mouth shield has not the common form, but there is a rounded angle within, and the outer part is not so much restricted. The ventral plates are more elongated, longer than broad ; outer edge usu- ally a little re-enteringly curved. The keel rather indistinct. The dorsal plates are more round than common; the radial shields very narrow, sepa- rated by some few scales. The scales of the disk resemble those of var. a, but are longer and narrower; the primary plates distinct. In other re- spects it resembles the typical form. (One specimen only.) In the typical form and var. 6 the spines may have a dark brown tint on the middle, and the mouth then has the same color. Several specimens from Stations 3384, 458 f. (typical form) ; 3393, 1020 f. (var. b); 3394, 511 £. (var. a); 3402, 421 f. (var. ¢) ; 3419, 772 f. (var. a); 8424, 676 £ (var. a). 27. Amphiura gymnogastra ». sp. Plate IX. Figs. 6-8. Diameter of disk, 9 mm.; width of arm close to disk, without spines, 1mm.; length of arms, about ten times the diameter of the disk. One rather long and stout conical mouth papilla on each side,* besides that on the apex. Mouth shield equally long and broad, almost rhomboidal, outer sides a little re-enteringly curved, inner sides straight, all the angles rounded, the inner angle more so than in the figure. Side mouth shields sometimes meeting within, sometimes separated, much broader without than within; they may also be quite triangular. * One specimen has two outer papilla on one mouth angle. 146 THE OPHIURIDZ. First ventral plate very small, six-sided; those beyond equally wide and long, rather broadly in contact; they have inner angle truncated, outer edge concave, outer corners rounded, outer laterals almost straight, inner ones re-enteringly curved. Side arm-plates with spine-ridge very little prominent; as usual there is a naked space separating the side plates of each two adjoining joints, that space being distinct also from the dorsal side. Dorsal plates in mutual contact, somewhat more broad. than long, with a rounded peak within and without, the latter however very indistinct ; inner sides‘a little re-enteringly curved, side corners rounded. Dorsal side of the disk covered with small, overlapping scales, among which the primary plates are not conspicuous. Radial shields about half as long as the radius of the disk, separated within by more small scales, without by one elongated scale, just meeting at their outer ends. Their adradial edge is straight, the abradial curved; inner end pointed, outer end broadly rounded. Outside the radial shields there are more small scales, and there is a rather deep, narrow incisure in the median line. The under side of the disk is quite naked, only the inner end of the genital scales being distinct. Five, farther out four, rather short, tapering arm-spines, increasing in length downwards, the lowest being as long as a joint. Two small tentacle scales, not standing at a right angle. Color in alcohol: gray. Five rather badly preserved specimens from Station 3392, 1270 f. This species is very closely related to A. semiernus Lym., and should per- haps not be considered as a separate species. It differs from that species in the form of the mouth shields and the ventral plates; the outer edge is more concave and the outer corners more prominent than in A. semiermis.* It is closely related also to A. lanceolata Lym., but in like manner separated from that species by the form of the mouth shield, and the ventral and dorsal plates. 28. Amphiura polyacantha n. sp. Plate IX. Figs. 3-5. Diameter of disk, 8 mm.; width of arm close to disk, without spines, 1.4 mm.; length of arms 10-11 times the diameter of the disk. One rather long, conical mouth papilla on each side, besides the infradental one. Mouth shield a little longer than wide, inner part strongly rounded, outer * We have had specimens of 4. semiermis determined by Lyman himself, for comparison. THE OPHIURIDZ. 147 part slightly restricted. Side mouth shields very short and wide, triangular, not meeting within. First ventral plate short, polygonal ; those beyond about as long as wide, the two-three inner ones, however, a little longer than the rest. They have all the inner angle truncated, outer edge concave, outer corners rounded, outer laterals almost straight, inner ones a little re-enteringly curved. Side arm-plates with spine-ridge little prominent. As usual in Amphiura, the side arm-plates of each two adjoining joints are separated by a naked space, which is very distinctly seen also from the dorsal side. The dorsal plates are almost egg-shaped in the inner part of the arm, farther out they become more transversely oval, and towards the end of the arm they again become egg-shaped ; they are in mutual contact almost to the end of the arm. The inner ones are a little longer than wide, farther out they are somewhat wider than long, and towards the end of the arm they are almost equally wide and long. The disk is partly naked; round the radial shields there is a broad band of small, but distinct, rounded, overlapping scales ; in the central part of the disk there are only some few irregular, spread scales, between which the naked skin is seen; and along the margin there is a completely naked band. The primary plates not distinct. The radial shields are narrow, elongated, with outer ends just meeting, inner ends separated by more small scales. Outside the radial shields there is a little naked space, sepa- rated from the naked band along the margin of the interbrachial spaces by a few scales, in continuation of those around the radial shields. A rather deep but very narrow incisure in the median line between the outer end of the radial shields. Under side of the disk wholly naked. Six, on the inner joints seven to eight arm-spines, the upper one about half the length of an arm-joint, then they gradually increase in length down- wards, the lowest being a little longer than a joint. They sometimes are a little widened at the end. Two small tentacle scales, making a right angle with each other, though not in the typical manner, as in A. Chiajet Forbes. Color in alcohol: dark gray. One specimen from Station 3353, 696 f. 148 ; THE OPHIURIDZ. 29. Amphiura seminuda n. sp. Plate XI. Figs. 1-3. Diameter of disk 6 mm.; width of arms close to disk, without spines, 1mm. ; length of arms unknown. One short, conical mouth papilla on each side ; the infradental papillae with inner end truncated and the abradial corner a little produced. Mouth shield equally wide and long, with an obtuse rounded angle within, inner sides curved, outer sides concave; side corners and outer edge rounded. Side mouth shields meeting within, broader without than within. First ventral plate small, elongated-hexagonal. Those beyond with inner end truncated, outer edge concave, outer corners rounded, outer laterals almost straight, inner re-enteringly curved. They are inconsider- ably longer than wide. Side arm-plates with spine-ridge not very prom- inent; the naked space which separates those of each two adjoining joints is not seen from the dorsal side. Dorsal plates transversely oval, with an indistinct angle within, about twice as broad as long. They are just in con- tact in the inner part of the arm. The dorsal side of the disk is covered by delicate, rounded, overlapping scales, among which the primary plates are not distinct. The radial shields almost semilunar, as long as half the radius of the disk; they are in contact in their outer half, their inner ends separated by a single row of scales. Outside the radial shields is seen only one very narrow scale. The incisure between the outer ends of the shields very small. Edge of the disk rounded, the margin almost straight. Under side of the disk naked, except that there is along the margin a band of scales, similar to those of the dorsal side. Genital scales distinct at the inner end. Three equally long, tapering, rather stout arm-spines, a little longer than an arm-joint. One small, rounded tentacle scale at the inner corner of the pores. Color in alcohol: pale brownish. One specimen from Station 3430, 852 £. sii “oy aoe aa “ya siamese ncaa THE OPHIURIDE. 149 30. Amphiura brevipes n. sp. Plate XI. Figs. 4-6. Diameter of disk, 8 mm.; width of arms close to disk, 1.3 mm.; length of arms not known with certainty, but evidently they are only about 4 to 5 times the diameter of the disk. One conical, rather short mouth papilla on each side; the infradental papille have the abradial corner produced. Mouth shield equally wide and long, almost rhomboidal, with a right angle within, side corners rounded and outer angle truncated ; inner sides straight, outer sides slightly concave. Side mouth shields short, very wide, meeting broadly within ; their outer end is considerably broader than the inner end. First ventral plate rather large, more than half the length of the second; those beyond the first equally long and wide, rather broadly in contact in the inner part of the arm; farther out it is only the tip of the inner angle which reaches the foregoing plate. Outer edge curved, outer corners much rounded ; inner and outer laterals slightly re-enteringly curved. Side arm- plates with rather prominent spine-ridge ; the naked space separating the side plates of each two adjoining joints also seen from the dorsal side. Dor- sal plates about twice as broad as long, just separated by the side arm-plates; they are transversely oval, their inner sides a little sigmoidly curved. Dorsal side of the disk covered with delicate, overlapping scales, among which the primary plates are not distinct, except the central plate. Radial shields scarcely half as long as the radius of the disk, separated in their whole length by one or two narrow, elongated scales. They are almost semilunar, the outer end truncated. Along their outer edge is a single row of small scales; almost no incisure in the disk. The under side of the disk is partly naked, though with some few spread scales; only along the margin there is a rather broad band of scales, like those on the dorsal side. Inner end of the genital scale just visible. Edge of the disk rounded, the margin a little re-enteringly curved. Three equal tapering arm-spines, as long as a joint. No tentacle scales. Color in alcohol: gray. One specimen from Station 3399, 1740 f. 8 150 THE OPHIURIDZ. 31. Amphiura gymnopora n. sp. Plate XI. Figs. 7-9. Diameter of disk, 6 mm.; width of arm close to disk, without spines, Imm.; length of arms about ten times the diameter of the disk. One very short, rounded mouth papilla on each side ; the infradental ones simply conical. Mouth shield a little longer than wide, with a rounded angle within, outer part restricted, side corners rounded, inner sides feebly curved. Side mouth shields mostly not meeting within; inner end very narrow, outer end much wider. First ventral plate small, six-sided; those beyond equally long and broad, just in contact, all with an angle within, and outer edge doubly curved, with a cut in the median line. Outer corners sharp, inner and outer laterals re-enteringly curved; there is a distinct keel along the median line. Side arm-plates with spine-ridge little prominent; the naked space separating the side plates of each two adjoining joints distinct also from the dorsal side. Dorsal plates transversely oval, in mutual contact, twice as broad as long. Dorsal side of the disk covered with small but distinct overlapping scales, among which the primary plates are not distinguishable, except the cen- tral plate. Radial shields scarcely half as long as the radius of the disk ; they are separated at their inner end by several small scales, at their outer end only by one elongated scale. Their adradial edge is straight, the abra- dial curved, especially towards the outer end, which is rather broad, almost straightly cut; the inner end is somewhat rounded. The under side of the disk covered by extremely small but distinct scales. The genital scales dis- tinct in the whole length. Edge of the disk rounded, the margin re-enter- ingly curved. Three tapering arm-spines, the median one inconsiderably longer than the others, a little longer than an arm-joint. No tentacle scales. Color in alcohol: dark gray. Several specimens from Station 3355, 182 f. THE OPHIURIDZ. 151 32. Amphiura Diomedes n. sp. Plate XII. Figs. 1-7. Diameter of disk 14 mm.; width of arm close to disk, 2 mm.; length of arms, 7-8 times the diameter of the disk. Two mouth papille on each side, widely separated from those on the apex; they are usually equally large, but sometimes the outer, sometimes the inner one is a little larger; the outer is rounded, the inner more or less conical. Mouth shield with the outer end somewhat restricted, an acute angle within, inner sides a little re-enteringly curved or almost straight, side corners rounded, outer edge straight. In the specimen figured they were wider than long; in some specimens they are equally wide and long; in these latter the inner sides are straight. Side mouth shields rather narrow, their outer end a little broader than the inner end; they just meet within. First ventral plate small, rounded, or five-sided. Those beyond a little more broad than long (in Figure 1 they are wrongly represented as being equally long and broad), ‘The second and third have the inner end trun- cated, those beyond have an angle within; on the inner three—four joints they are in mutual contact, then distinctly though not widely separated. The outer edge is concave, outer corners slightly rounded; outer Jaterals almost straight, inner a little re-enteringly curved. Side arm-plates with spine-ridge little prominent; the naked space separating the side plates is rather small, not seen from the dorsal side. Dorsal plates more than twice as broad as long, with a very obtuse angle within, and outer edge slightly curved, rounding very abruptly at the sides; inner sides re-enter- ingly curved. They are in contact until far out on the arm, but only the first ones have the inner angle truncated. At the base of the arm are seen one or more small, rudimentary dorsal plates. The arm is rather flat and broad, with a feeble keel above. The disk is covered with small, overlapping scales, among which the pri- mary plates are distinct. The scales of the under side are smaller; usually they continue over the edge to the dorsal side, where they are very conspic- uous, being directed opposite to those of the dorsal side. Usually there are a few more conspicuous scales joining the mouth shield. The radial shields are about as long as half the radius of the disk, wholly separated at the ‘inner end by more small scales, at the outer end by a single row of larger 152 THE OPHIURIDZ. scales; their adradial side is almost straight, the abradial curved ; inner end shortly pointed, outer end so truncated that there results a rather deep curve above the arm. Outside the radial shields there is a single row of small scales or a single narrow scale. Usually the inner end of the genital scale is distinct. The margin of the disk is re-enteringly curved, the edge rounded. Three tapering arm-spines, the middle the longest, a little longer than an arm-joint. Two tentacle scales, wide, rounded, forming a right angle with each other. ; Color in alcohol: disk bluish, often with a reddish tint at the outer end of the radial shields; arms white or pale brown. Several large specimens from Stations 3393, 1020 f.; 8394, 511 f.; 3398, 1573 f.; and 3429, 919 f. A large, fine species, which is not very variable. The mouth shields, as above said, are the most variable in form; outer edge of the ventral plates sometimes straight ora little convex. The dorsal plates may be separated also on the inner joints. There are seldom three outer mouth papille, and never on all the mouth angles of the same specimen. One specimen (3398) has a small papilla between the two outer mouth papille (Fig. 4); also the mouth and side mouth shields are here of another form than the common one. However, there can be no doubt that it is the same species. From Station 3392, 1270 f., there are three specimens, from Station 3429 one, which differ somewhat from the other specimens of A. Diomedee (Figs. 5-7). They are all smaller than the specimens from the other sta- tions, and it may be they are only younger specimens of A. Diomedee ; or it may be they are to be considered as a variety of that species; they can scarcely be regarded as a separate species. Differences from the typical form are seen in the shape of the mouth and the side mouth shields; but on that feature no stress can be laid, as it is also rather variable in the typi- cal form ; nor is it wholly alike in these four specimens. The first ventral plate has a distinct angle within, and is rather large. In the specimen from Station 3429 the dorsal plates are transversely oval, not of the typical form. The margin of the disk is convex. } THE OPHIURIDZ. 153 33. Amphiura assimilis n. sp. Plate X. Figs. 5-7. Diameter of disk, 13 mm.; width of arm close to disk, 2 mm.; length of arms, c. 5-6 times the diameter of the disk. Two (in one specimen three) small rounded, almost equally large mouth papillz on each side, be- sides those on the apex. The papilla of the first mouth tentacle is very distinct, almost at the same level as the true mouth papillae. Mouth shield equally wide and long, with the outer part restricted; an obtuse angle within, sides somewhat irregularly sigmoidly curved, corners rounded, outer edge straight. Side mouth shields a little broader without than within, where they meet. First ventral plate small, six-sided or rounded ; those beyond considerably broader than long. They are rather broadly in contact, their inner end thus being truncated ; farther out they are more or less distinctly separated from each other, and have then an angle within. The outer edge, inner and outer laterals, a little re-enteringly curved, outer corners rounded. Side arm-plates, with spine-ridge not very prominent (though somewhat more than shown in the figures). There is a little naked space between the side arm-plates, not seen from the dorsal side. (Figure 5 is not correct in this respect.) The dorsal plates are thrice as broad as long, with outer edge slightly curved, a little concave on each side; inner sides almost straight, outer corners rather sharp; they are broadly in contact, the inner angle very obtuse, truncated. The under side of the arms flat, the dorsal side much rounded. Disk covered with rather large, delicate, overlapping scales, among which the primary plates are more or less distinct (scarcely at all in the specimen figured). The radial shields pearseed-shaped, wholly separated by some few rather large scales; they are pointed within, their outer edge rather broad, straightly cut. Outside the radial shields are seen one or several narrow scales. The scales of the under side smaller than those of the dorsal side ; usually there is one rather conspicuous scale joining the mouth shield. Genital scales not distinct. Margin of the disk convex, the edge rounded. Three equal, short, thick arm-spines, scarcely longer than half the length of an arm-joint. Two (seldom three) small tentacle scales, rather irregu- larly arranged: that on the ventral plate is distinct only in the inner part of 154 THE OPHIURIDZ. the arm, and even here not on each joint; that on the side arm-plate, which is usually placed at the base of the lower arm-spine, may be distinct far out on the arm, but not to the end; sometimes, however, the latter scale is the first to disappear, sometimes only a few of the inner pores have ten- tacle scales at all. Color in alcohol: gray. Three specimens from Station 3374, 1823 f. One of the specimens has the mouth shields quite irregularly formed. The two species, A. Diomedew and