22 NATURAL HISTORY BULLETIN 



Genus Leptasterias Verrill. 



Leptasterias Verrill, Proc. Boston Soc. Nat. Hist., x, p. 350, 1866. Type, 

 A. miilleri Sars. Sladen, Voy. Chall., xxx, p. 563, 1889. Perrier, Exp. 

 Trav. et Talism., p. 108, 1894. Verrill, op. cit., p. 116, 1814a. 



An extensive group of small, more or less diplacanthid star- 

 fishes, closely related to typical Asterias, usually with, a single 

 row of peractinal plates and spines. Rays five or six. The more 

 typical forms have slender rays and a small disk, vsdth the dorsal 

 ossicles irregularly arranged, or showing several imbricated ra- 

 dial rows, with numerous spines. It differs from typical Asterias 

 in the diminished number and larger size of the dorsal and lat- 

 eral papulee, and the small number of actinal plates, of which 

 there is generally only a single row, but more profoundly in hav- 

 ing the genital pores on the actinal side, near the mouth, and in 

 the ovaries, which are different in form and produce larger eggs, 

 which have an abbreviated development, passing through no 

 free-swimming larval stages. 



The eggs and young are carried in clusters, adhering in front 

 of or around the mouth in all the species studied in the breeding 

 season, 



Leptasterias fascicularis (Per.) Verrill. 

 Asterias fascicularis Perrier, op. cit., 1881, p. 1; Mem. Etoiles de Mer, 

 p. 200, pi. iii, fig. 3, 1884. 



The type had the radii Q"^"' and 57°™ ; ratio, 1—6.3. The five 

 slender rays are slightly contracted proximally. The dorsal and 

 dorso-lateral surfaces of the rays have about seven alternating 

 rows of plates, separated by papular areas smaller than the 

 plates, and containing usually two papulaB, and holding about 

 two or three dermal minor pedicellariae. 



The plates of the median row have a curved row of three or 

 four short, blunt spines ; those of the other rows have one or two 

 similar spines ; some single spines are also situated on the inter- 

 polated ossicles. 



The disk is small and covered with spines like those of the 

 rays ; between them are some oval major pedicellariae with curved 

 valves, touching only at tips. 



On the under side of the rays there are two rows of plates, 

 near the adambulaerals ; each plate bears a single spine and often 

 a dermal minor pedicellaria. 



