PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 769 



of the Indian Ocean, 1912, p. 10 (occurs in Hawaiian Is.), p. 27 (range in detail), p. 63 (in key), p. 



247 (original reference; type) ; Die Crinolden der Antarktis, 1915, pp. 120, 121 (history and status; 



closely related to Pentamelrocrinus). 

 Peniamctrocrinus (part) A. H. Clark, Mem. Australian Mus., vol. 4, 1911, p. 796; Crinoids of the 



Indian Ocean, 1912, p. 32. 

 Thaumatrocrinus Koehler, Les fichinodermes des mers d'Europe, vol. 1, 1924, p. 58 (editorial error). 

 Promachrocrinus Koehler, Les fichinodermes des mers d'Europe, vol. 1, 1924, p. 58 (editorial error). 



Diagnosis. — A genus of Pentametrocrinidae in which the adult has 10 radials 

 from each of which arises an undivided arm (possibly irregularly branching distally 

 in one species). 



Type species. — Thaumatocrinus renovatus P. H. Carpenter, 1883. 



Qeographical range. — From southwestern Japan southward to the East Indies, 

 thence westward to the Laccadive Islands; Antarctic regions; southwest and west of 

 Iceland. 



Bathymetrical range. — ^Froin 660 to 3290 meters. 



Thermal range.— From 0.83° C. to 5.50° C. 



KEY TO THE SPECIES OF THAUMATOCRINUS 



[by A.M.C.] 



o'. Gonads in serial form along the pinnules, with an expanded sac corresponding to each pinnule 

 segment, thus appearing moniliform; the arms may be over 300 mm. in length and irregularly 

 branched (off the Maldive and Laccadive Islands, Indian Ocean; 914-1285 meters). 



investigatoris (p. 769) 

 a'. Gonads undivided, ovoid, concentrated on a few pinnule segments towards the base: arms not 

 known to exceed 250 ram. and unbranched. 

 6'. Probably large species growing to a size of 9 mm. diameter of centrodorsal; cirri XXX-C. 

 c'. Centrodorsal flattened hemispherical. 



d'. Cirri about C when the centrodoreal is 9 mm. in diameter; proximal part of the arms 

 broad, very rugged, with well developed articular tubercles (Hawaiian Islands; 1393-1828 



meters) rugosus (p. 772) 



d*. Cirri about LX when the centrodorsal is 9 mm. in diameter; proximal part of the arms 

 smooth, articular tubercles not very prominent (southeast of the Philippines; 914-1264 



meters) naresi (p. 773) 



c'. Centrodorsal low conical; cirri about LXXX when the centrodorsal diameter is 9 mm. 



(southwestern Japan; 600 meters) borealis (p. 775) 



6'. Size apparently small, not known to exceed 3.5 mm. diameter of centrodorsal; cirri up to XX. 



c'. Southern Ocean; 2425-3290 meters renovatus (p. 776) 



c'. West of Iceland; 823-2075 meters jungerseni (p. 782) 



[Note BY A.M. C] Since a reexamination of the specimens of renovatus in the British Museum 

 h.is shown that the third cirrus segments are not necessarily elongated, the use of this character in 

 the key by Mr. Clark to distinguish renovatus from jungerseni does not hold up. I can see no other 

 significant difference between them but the geographical separation. 



THAUMATOCRINUS INVESTIGATORIS, sp. noT. A. H. Clark 



FiouRE 48 



Decametrocrinus, sp. A. H. Clark, Crinoids of the Indian Ocean, 1912, p. 248, fig. 47,a,5, p. 249 



(description; Investigator sta. 124); John Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 



1937, p. 98. 

 Thaumatocrinus, sp. A. H. Clark, Die Crinolden der Antarktis, 1915, p. 150 (same record); John 



Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1937, p. 87, p. 98 (Mabakiss sta. 158; 



description; remarks), p. 102. 



