170 THE VOYAGE OF H.M.S. CHALLENGER. 



a number of spiniform granules, which are most robust and elongate on the adoral half 

 of the plate. Beyond this, these appendages do not appear to present any special 

 arrangement or to form definite series, and they impart a very echinulate aspect to the 

 mouth-angles. 



The actinal interradial areas, which are large, are covered with membrane and minute 

 subspiniform, conical granules. These are small, numerous, rather closely placed, and 

 distributed over the whole area; here and there a faint appearance of grouping may be 

 observed, which seems to suggest the indication of the actinal intermediate plates. Of 

 the actual outline, arrangemeut, or character of these plates no observations can be made, 

 owing to the uniform and thick covering of membrane with which they are overlaid. 



Colour in alcohol, yellowish white, the paxillar area having a rather browner shade. 



Locality. — Station 89. Off the west coast of Africa, between the Canary Islands and 

 tbe Cape Verde Islands. July 23, 1873. Lat. 22° 18' 0" N., long. 22° 2' 0" W. Depth 

 2400 fathoms. Globigerina ooze. Bottom temperature 36° '6 Fahr.; surface temperature 

 73°-5 Fahr. 



Remarks. — I know of no other starfish with which this remarkable and elegant form 

 can be confounded. 



Subfamily Ctenodiscin^:, Sladen, 1886. 

 Genus Ctenodiscus, Mtiller and Troschel. 



Ctenodiscus, Miiller and Troschel, System der Asteriden, 1842, p. 76. 



Anodiscus (? Valenciennes, M.S.), Perrier, Ann. ScL Nat., 1869, 5e Sen, t. xii. p. 298. 



I have on a preceding page (p. 125) stated my reasons for associating this genus 

 with the Porcellanasteridae, and I have also remarked on the presence of an extremely 

 minute pore at the extremity of the epiproctal cone, which is more or less prominently 

 developed in the centre of the abactinal area. 



Chorology of the Genus Ctenodiscus. 

 a. Geographical distribution : — 



Atlantic : Two species : — one between the parallels of 60° and 80° N, the 

 other between the parallels of 30° and 60° S. 



Ctenodiscus corniculatus off the Scandinavian and North 

 American coasts, off Greenland, Spitzbergen, and Nova Zembla, 

 and in the Kara Sea. Ctenodiscus australis off the eastern coast 

 of the southern point of America. 

 Pacific : One species between the parallels of 40° and 60° S. 



Ctenodiscus procurator off the western coast of the southern 

 point of America. 



