3 
108 ‘“ ENDEAVOUR ” SCIENTIFIC RESULTS. 
lowest 7 or 8 carry primary tubercles and spines ; interambu- 
lacral areas abactinally only about 8 mm. broad. Ambulacral 
plates 12, each with a large primary tubercle; ambu- 
lacra 13mm. 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- 
cellariz. 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 slight but distinct longi- 
tudinal ridges, and there are six such paraliel 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,” 7.e., has no smooth, 
polished surface. Actinal primaries very flat, thin, slightly 
curved, abruptly truncate, about half collar. Secondary 
spines, cylindrical or terete, stout and blunt, 4-5 mm. long. 
Pedicellariz abundant; the valves of the ophicephalous are 
not at all constricted as in C. floridanus, 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 imterambulacral 
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 very 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 
light 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. floridanus 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 
