A MONOGRAPH OF THE EXISTING CRINOIDS 69 



Paleontology which was published in 1913. In this we correlated the classification 

 of the recent forms which I had previously worked out on the basis of living mate- 

 rial alone with the currently accepted classification of the fossil types. The system- 

 atic scheme which we adopted is given in the introduction on page 53. 



KET TO THE FAMILIES AND HIGHER GROUPa OF THE COMATULIDS 



a'. Cavitj' in the centrodorsal containing the chambered organ and overlying structures very small 

 and shallow; rosette sunk below the dorsal surface of the radial pentagon, and with both the 

 radial and iuterradial processes forming "spoutlike" processes; central portion of the radial 

 pentagon more or less completely filled with irregular calcareous deposit which forms a 

 central plug; plane of the muscular fossae on the radial articular faces making a considerable 

 angle with the dorsoventral axis, or the muscular fossae very greatly reduced; joint face 

 elements distal to the transverse ridge not at all, or only slightly, excavated interiorly; bra- 

 chials from about the fourteenth onward short, usually much broader than long; second 

 syzygy in the arms beyond the ninth brachial; brachial syzygies usually more or less widely 

 and irregularly spaced; pinnules, at least the proximal, wholly or in part prismatic, with a 

 dorsal carination, which may be confined to the earlier segments; segments of the distal 

 pinnules beyond the third not especially slender or elongated, and the first 2 not appreciably 

 broadened; never more than 5 radials; arms very commonly more than 10 (of general occur- 

 rence, but absent from the Arctic regions and the north Atlantic north of the Bay of Biscay 

 and North Carolina, the Mediterranean Sea, the west coast of North and South America, 

 the Bering and Okhotsk Seas and all but the southeastern portion of the Sea of Japan, and 



the shores of the Antarctic Continent; littoral to abyssal) Oligophreata, p. 74. 



fc'. Lowest pinnules with a comblike structure at the tip; mouth usuaUy more or less marginal, 

 and anal tube usually more or less central; sacculi very rarely present (Japan and Poly- 

 nesia to New Zealand and Tasmania, westward to the whole east coast of Africa; north- 

 western Africa and southwestern Europe; North Carolina to Brazil; chiefly littoral and 

 sublittoral, but a few species are found in fairly deep water). 



Comasterida ; Comasteridae, p. 76. 

 cK Cirri present. 



d'. Arms 10 or more; if the arms are more than 10, the first biachial syzygy is between 

 brachials l-t-2 or 2-|-3. 

 e'. Cirri with dorsal spines or tubercles on the outer segments; division series all 2, or the 

 II Br series 4 (3-1-4), exceptionally 2, and the following series 3 (2-|-3); genital pinnules 

 not especially stout, the component segments not noticeably short (Japan and Poly- 

 nesia to Tasmania and westward to east Africa; northwestern Africa and the Bay of 

 Biscay; North Carolina to Brazil; chiefly littoral and sublittoral, but in the .Atlantic 



found also in fairly deep water) Capillasterinae, p. 86. 



e^. Outer cirrus segments entirely without dorsal spines or tubercles; IIBr and IIIBr 

 series, if present, 2 (l-f-2); genital pinnules usually composed of relatively short and 

 broad segments (southwestern Japan to southern Australia and westward to the 

 Andaman Islands; North Carolina to Brazil; chiefly littoral, but a few s])ecies arc 



found in fairly deep water) Comactiniinae, p. 293. 



d^. Always more than 10 arms; first brachial syzygy between brachials 3-t-4 (Japan and 

 Polynesia to New Zealand and Tasmania, and westward to Madagascar and South 



Africa; littoral and sublittoral) Comasterinae, p. 404. 



c^. No cirri. 



dK First brachial of the free undivided arms bearing the first pinnule; first syzygy between 

 brachials 2-f3; IIBr series 4 (3-|-4) and following division series 3 (2-|-3) (China Sea to 



Borneo; littoral and sublittoral) Capillasterinae, p. 85. 



d'. Second brachial of the free undivided arms bearing the first pinnule; a syzygy between 

 brachials 3-|-4, sometimes also between brachials l-f2, but never between brachials 

 2-|-3; division series never 3 (2-|-3). 



