ASPIDODIADEMA NICOBARICUM. 95 



Slendci' bidcntate pedicelltirios, abundant, of very variable size and form ; 

 usually the valves are straight and meet either for their full length or only 

 at the tip, but in some Nicobarian specimens they are conspicuously curved. 

 The length of the valves ranges froui .60 to 1.65 mm., and the margin is 

 either smooth or finely serrate, rarely coarsely dentate. 



Stout tridentate pedicellariaj, rare and often wanting in Hawaiian speci- 

 mens, wholly wanting in Nicobarian specimens, common or sometimes 

 infrequent in specimens from the Kei Islands. The valves are either 

 about a millimeter long and nearly as wide, with a tooth at the tip 

 (specimens from Kei), or they are over a millimeter and a half long, only 

 a little more than half as wide, and rounded at the tip (specimens from 

 Hawaii). 



Ophice2)halous pedicellarise are of the usual form and size, and exhibit 

 little diversity. There are 3 glands on the stalk, and in specimens from 

 Kei and Hawaii there are 3 valves in the head ; specimens from Nicobar 

 have 4 valves. 



Triphi/llous pedicellarice are common, and exhibit no special peculiarities. 

 The valves are relatively narrower at the tip, and the lower part of the 

 blade is thicker in specimens from Kei than in those from either Nicobar 

 or Hawaii. 



Such diversity of pedicellaria? naturally suggests the possibility that we 

 are dealing with three different species, but it appears to be impossible to 

 point out any constant character of any kind by which specimens from the 

 three widely separated localities where this species has been taken can be 

 distinguished from each other. Possibly an actual comparison of specimens 

 might reveal some tangible differences, but Doderlein's and de Meijere's 

 descriptions are so detailed they seem to leave no reasonable ground for 

 such an expectation. 



This species was taken by the " Albatross " at the following stations : 



Station 3892. Off Mokapu Islet, N. coast of Molokai, Hawaiian Islands. 

 Bott. temp. 42.5°. 328-414 fathoms. Fne. gy. s. 



Station 3981. Off Nawiliwili Light, Kauai, II. I. 414-636 fathoms. 

 Glob. oz. 



Station 3988. Off Hanamaulu, Kauai, H. I. Bott. temp. 40 . 165-469 

 fathoms. Gy. for. s. p. 



Station 3989. Off Hanamaulu, Kauai, H. I. Bott. temp. 37.5°. 385-500 

 fathoms. Co. s. r. 



