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



Remarks. — This species has such very definite characters that it is not likely to be 

 confounded with any other. The spiny calyx and the double row of long hook-like 

 spines along the arms distinguish it very clearly. The radial axillaries come into contact 

 above the depressed lateral portions of the second radials just as in Antedon acuticirra, 

 and there is much the same sort of relation between the first and the second brachials. 

 It is rather a robust species for such a considerable depth (1600 fathoms). But the 

 sacculi are poorly developed, as is so often the case in the abyssal Comatulse. 



10. Antedon latipinna, n. sp. (PI. X. fig. 3). 

 Specific formula — A. . 



Description of an Individual. — Centro-dorsal subcorneal and marked by twenty 

 cirrus-sockets disposed in ten vertical rows. About forty joints in the cirri, a few of 

 them longer than wide. The remainder' are shorter and begin to overlap dorsally so as 

 to develop a sharp spinous keel. 



First radials partly visible ; the second rather convex, short and oblong ; axillaries 

 pentagonal, with slight backward projections, wider than the second, but barely twice as 

 long. Both joints, together with the first two brachials and the hypozygal of the third, 

 have straight lateral edges and small portions of the outer sides flattened. 



Ten arms, of short and smooth quadrate joints. Syzygies in the third and twelfth 

 brachials, with others at intervals of seven to nine joints. 



The second brachial has a short stout pinnule of about fifteen joints, the lowest of 

 which are short, wide, and slightly carinate, but not flattened laterally. The following 

 pinnules diminish to about the third pair and then gradually increase, their joints 

 becoming elongated. Disk much incised and well plated. Side plates fairly distinct on 

 the pinnule-ambulacra ; sacculi apparently absent. 



Colour in spirit, — light brownish-white. 



Disk about 4 mm.; spread probably about 8 cm. 



Locality.— Station 232, May 12, 1875; lat. 35° 11' N., long. 139° 28' E., 

 345 fathoms ; green mud; bottom temperature, 41°"1 F. One mutilated individual. 



Remarks. — This species differs from all the preceding ones in the characters of the 

 first pinnule, the lowest joints of which, though wide and slightly carinate, have no 

 indication of the flattening on the outer side which is so characteristic of Antedon valida 

 (PI. XV. figs. 5, 6), Antedon breviradia and others. The first two brachials and the 

 hypozygal of the third have the usual wall-like sides and straight edges, but these features 

 are less marked on the two outer radials. The cirri are arranged in ten very regular rows 

 on the centro-dorsal, which is another character of separation from the species previously 



