A. E. Verrill — N'orth American Ophiuroidea. 311 



II. — Arm-spines six, short. Oral shield acute-angled at both ends. 

 Dorsal arm-plates broad, ovate. 



A. Atlantica Ljung., '66. Off St. Helena. 



Tck. — Arm-spines three to five, slender, straight. Radial shields 



divergent. 

 J77. — Arm-spines four or five, short. A rudimentary tentacle-scale 



sometimes present, usually wanting. 



*A.fragiKs Yerrill, '85. Arm-spines four or five, subequal, tips 

 rough. U. S. East Coast. 



mm. — Arm-spines three or four, equal, slender, straight. Radial 

 shields small, touching distally, little divergent. Disk 

 scales small, in rosette. Disk partly naked below. 



* A. exigua Verrill, sp. nov. Gulf of St. Lawrence. 



jj. — Disk entirely covered with scales below. Radial shields 

 stout, largely joined, not divergent. Arm-spines three or 

 four, equal, straight. Disk-scales rather coarse. 



* A. Canadensis Verrill, sp. nov. Gulf of St. Lawrence. 



II. — Amphiocnida, gen or snh-gen. nov. (see page 316). 



Disk-scales bear small acute spinules. Arm-spines five to ten. 

 Tentacle-scale usually absent. (No American species known.) 



AMPHIPHOLIS Ljiing. (restr.) 

 Type, A. Jamiarii Ljung. 



Amphipholis lujwng., Ofvers. Kongl. Vet. Akad. Forhandl., p. 165, 1866; op. 



cit., p. 311 ; op. cit., p. 644, 1871. 

 Amphiura (pars) Lyman, Illust. Cat. Mus. Comj). Zool., i, p. 115, 1865; Bull. 



Mus. Comp. Zool., i, pp. 335, 339, 1869 ; Voy. Chall., v., pp. 122, 125, 1882. 

 AmphipholiH (restr.) Ver., Oph. Bahama Exped., v, p. 24, 1899. 



Three or four oral papillae form a continuous series along the 

 whole edge of the jaw ; of these the distal one is attached more or 

 less to the adoral shield and is operculiform or flat, and often much 

 broader than the others. The two inner are usually small and coni- 

 cal. Disk generally covered with naked scales, but in one species 

 bearing a few spines (Sec. AA). Radial shields naked and usually in 

 close contact along the whole or most of their length. Arm-sj)ines 

 generally three (rarely four), small, slender, tapered. Tentacle-scales 

 one or two, sometimes none. 



