ASTEROIDEA 257 



If the adambulacral armature is disregarded, a South Georgian specimen of D. 

 meridionalis would serve to illustrate a 6-rayed octoradiata; or a 7-rayed octoradiata 

 would pass for meridiotiaUs (of which there are 2 small 7-rayed specimens from St. 140). 

 Octoradiata has regularly a variable number of sporadic diplacanthid adambulacrals, as 

 noted in connection with young examples. 



The crossed pedicellariae are closely similar in size and form, ranging from 0-34 to 

 0-39 mm. in length abactinally, and 0-45-0-55 mm. on inferomarginals. In profile the 

 terminal lip in meridionalis descends slightly further than in octoradiata. The lanceolate 

 straight pedicellariae are usually a little heavier in meridionalis. 



Diplasterias radiata (Koehler) 



(Fig. M, z-^b) 



Cosmasterias radiata Koehler, 1923, p. 36, pi. 2, fig. 5; pi. 3, figs, i, 2. 



St. 160. Near Shag Rocks, 53° 43' 40" S, 43° 57' W, 177 m., grey mud, stones and rock, 3 speci- 

 mens. 



Like Koehler's specimens, these are unfortunately young ; two have 8 rays and one has 

 9. R is 16 mm., 13 mm., 7 mm. A few of the proximal adambulacrals are monacanthid 

 and rest diplacanthid. 



The crossed pedicellariae are of the rather noncommittal Diplasterias form, 0-27- 

 0-33 mm. long and the terminal lip is more like that of D. meridionalis than of octo- 

 radiata— mmdy , more extensive in profile. Ahhough these specimens are very small, the 

 largest pedicellariae are about the same size as the smallest pedicellariae of a full grown 

 octoradiata (o-34-o-55 mm.). In the actinal interradial area of one specimen are i or 2 

 lanceolate straight pedicellariae about 0-85 mm. long, while those on the adambulacral 

 margin are about 0-35 mm. long. In the largest specimen the axillary pedicellariae are 

 no larger than the adambulacral while in the smallest they are absent. 



It is unprofitable to hold too strong opinions concerning the generic position of this 

 young form. From its resemblance to octoradiata I believe it is better to place it m 

 Diplasterias than Cosmasterias. 



Type locality. Shag Rocks, 160 m. 



Genus Cryptasterias Verrill 



Diplasterias Koehler, part, 1906, p. 19; 1908, p. 574. 



Cryptasterias Verrill, 1914, p. 362. Type Diplasterias turqueti Koehler.— Koehler, 1920, p. 57; 1923, 

 p. 25. — Fisher, 1923, p. 604; 1930, p. 228. 



Cryptasterias turqueti (Koehler) 



Diplasterias turqueti Koehler, 1906, p. 19, pi. 2, fig. 17; pi. 4, fig. 39; 1908, p. 574. 

 Cryptasterias turqueti Verrill, 1914, p. 362.— Koehler, 1920, p. 57, pi. 17, figs. 1-5.— Fisher, 1920, 

 p. 228. 

 St. 165. Dove Strait, south-east of Queen's Bay, Signy Island, South Orkneys, 10 m., i specimen. 



