OPHIUROIDEA 231 



(Lyman) (Syn. Opkiogli/pha convexa Lyman), found in various 

 places between Madeira and the Azores (" Princesse Alice "), and 

 in the Bay of Biscay (" Michael Sars "), 3825-4700 m. ; also 

 known from off New England ("Albatross ") and from the S. 

 Atlantic and the Pacific (" Challenger "), ca. 2940-4700 m. ; 

 A. saurura (Verrill) (Syn. Ophioglypha saurura Verrill ; Ophio- 

 glypha aspera Koehler), found at 62° 10' N., 19° 36' W., 2060 m. 

 (" Thor "), elsewhere known from off N. America, ca. 850-1270 

 m. ("Albatross", " Hirondelle "). These four species are dis- 

 tinguished as follows : 



1. Mouth shields very large, occupying nearly the whole inter- 



radial space ........ 2 



Mouth shields small, not reaching halfway to the edge of disk ; 

 plates of dorsal side of disk thick, small, with primary plates 

 fairly conspicuous ; radial shields separate or just meeting at 

 the distal end. Arms serrate -carinate . A. saurura (Verrill) 



2. Primary plates not separated by smaller plates, very large, 



occupying nearly the whole disk. Radial shields contiguous. 



(" Challenger " Oph., PI. VI. 13-15) . A. convexa (Lym.) 



Primary plates separated by smaller scales ; radial shields not 



contiguous ......... 3 



3. Primary plates fairly large ; pores very large, well beyond disk 



still having 4 tentacle scales at inner side 



A. hullata (Wyv. Thoms.) 



4. Primary plates not much larger than the other scales ; already 



the fourth pore pair with only 2 tentacle scales at inner side, 

 then only one (" Monaco ", xxxiv., PL XXV. 9-11) 



A. abdita (Koehler) 



[Homalophiura H. L. Clark.] 

 The two species of this genus recorded from the N.E. Atlantic 

 are : H. inornata (Lym.), (Syn. Ophioglypha inornata Lym. ; 

 0. indivisa Ltk. and Mrtsn.), found off the Azores and Canaries, 

 640-2995 m. (" Tahsman "), known elsewhere from the Indo- 

 Pacific, 470-3330 m. ; H. tesselata (Verrill) (Syn. Ophioglypha 

 tesselata Verrill), found off the Azores and from the Bay of 

 Biscay to the Cape Verde Islands, 1267-2870 m. ; also known 

 from the east coast of N. America, 458-3720 m.^ The two species 

 are thus distinguished : 



1 In Les Echinodermes des mers d' Europe (p. 331) Koehler states that 

 Ophiura {Homalophiura) confragosa Lyman has also been found off Portugal, 

 in a depth of 1000-2000 m. This must rest on a slip of the memory. 

 So far as the author can find, this species has only been found by the 

 " Challenger " in the S. Atlantic, off the La Plata River, 1080 m. 



