288 DEEP-SEA ECHINODERMS 



ing 1500 fathoms. Among them is Astronyx loveni, a 

 Norwegian species, also inhabiting deep water off 

 Japan, which was taken by the Investigator in 406 

 fathoms off the Travancore coast. Another interesting 

 species is Ophiotypa simplex, Koehler (Fig. 87), from the 

 tremendous depth of 1997 fathoms, which, though aduh, 

 retains an embryonic simplicity in the form of its exo- 

 skeleton, the arrangement of the dorsal plates of which 

 is suggestive of the elements of the cup of a Crinoid. 



Though the Crinoids, both Feather-stars and 

 Stalked Sea-lilies are represented in the depths of the 

 seas of India, the number of species discovered by the 

 Investigator is very small, nor have they yet been 

 sufficiently examined. 



On the other hand the abyssal Sea-urchins of 

 Indian latitudes are fairly abundant in species and 

 amazingly prolific in individuals : in fact, many of our 

 deep-sea Echinoids, such as Phormosoma, Dorocidaris, 

 PalcBOpneiistes (Fig. 22), and Lovenia gregalis (Fig. 

 88), appear to be in the highest degree gregarious. 

 Except that their shells are much thinner, and their 

 spines sparser and more delicate, the sea-urchins of 

 the depths are not strikingly different in general 

 appearance, or even in colour, from those of the 

 regions near shore, though of course they are, in the 

 main, utterly different, generically, from any of the 

 littoral species of these latitudes. 



