108 " ENDEAVOUR " SCIENTIFIC RESULTS. 



lowest 7 or 8 carry primary tubercles and spines ; interambu- 

 lacral areas abactinally only about 8 mm. broad. Ambulacrall 

 plates 12, each with a large primary tubercle ; ambu- 

 lacra 13 mm. wide at ambitus, where interambulacra are 

 about 11, but only 8 mm. abactinally where interambulacra 

 are 8. Primary tubercles large and smooth, without crenula- 

 tion or perforation, of course. Abactinal system about 11 

 mm. across; oculars all exsert ; anal system, 5.5 mm. across, 

 covered by 4 similar, triangular plates. Actinostome some 

 16 mm. across, bare, except for the ring of buccal plates, close 

 around the mouth which bear numerous, ophicephalus pedi- 

 cellariae. Primary spines, when fully developed, 85 mm. long, 

 distinctly curved, tapering to a blunt point, which is nearly 

 always broken off ; collar about 11 mm. long or about .13 of 

 spine-length ; it is very slightly further advanced on the 

 dorsal keel of the spine than on the lower surface ; on each 

 side of the keel on the collar are two sKght but distinct longi- 

 tudinal ridges, and there are six such parallel ridges on the 

 lower side of the collar ; on most of the primaries above the 

 ambitus the collar is much longer, .30-. 45 of spine-length, or 

 the uppermost spine or two is all " collar," i.e., has no smooth,, 

 polished surface. Actinal primaries very fiat, thin, sUghtly 

 curved, abruptly truncate, about half collar. Secondary 

 spines, cylindrical or terete, stout and blunt, 4-5 mm. long. 

 Pedicellariae abundant; the valves of the ophicephalous are 

 not at all constricted as in C. floridayius, but on the other hand 

 are not so wide and blunt at tip as in C. longicollis. Colour of 

 test much as in C. floridanus and C. longicollis, light brownish, 

 or dirty cream-colour, with ocular plates, outer borders of 

 genital plates, outer portion of abactinal interambulacral 

 plates, and a narrow, zigzag, median ambulacral line, vermil- 

 lion red ; inner portion of abactinal interambulacral plates 

 more or less lavender or rose-purple (according to dryness and 

 conditions of lighting) ; secondary spines abactinally reddish- 

 brown ; uppermost primaries and collars of the others very 

 light gray-brown with, often, a greenish tinge ; in mature 

 primaries the polished portion is light apple-green adjoining 

 the collar, on upper surface, but verj^ quickly passes into 

 bright red (not abruptly, however) ; at the very tip of the 

 spine may be one or two rather broad transverse bands of 

 Ught green ; lower surface of primaries, pure white ; actinal 

 primaries white, with collar pale grayish or gray-brown. 



This is a very typical Coelopleurus and closely related to 

 C. floridamis and C. longicollis, but it differs from both in the 

 character of the dorsal interambulacra. The difference is 

 marked when specimens are compared, but it is less easy to 



