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PACIFIC SCIENCE, Vol. XVII, July 1963 
Crystallophrisson hancocki n. sp. 
Figs. 14, 15 
COLLECTIONS: 
2411 (2) in 400 fm, with Prochaetoderma 
calif ornicum and C. hartmani. 
2412 (1) in 324 fm, with Limifossor fratula 
and C. hartmani. 
2475 (1) in 405 fm. 
2497 (1) in 24 fm. 
2628 (1) in 350 fm. 
2641 (1) in 373 fm. 
2723 (2) in 325 fm, with Limifossor fratula 
and C. hartmani. 
2839 (2) in 446 fm, with C. hartmani and 
Prochaetoderma calif ornicum. 
2888 (1) in 390 fm. 
2901 (2) in 310 fm. 
DIAGNOSIS: This species is of moderate size 
and measures between 19 and 25 mm long, 
with a fairly large prothorax (Fig. 15). The 
color in alcohol is brownish-gray. The spines 
are large but weak, and most of them lack a 
marked keel (Fig. 14). The body is distinctly 
narrowed between the preabdomen and the 
slender and somewhat elongated postabdomen; 
on the latter the slitlike dorsoterminal sense 
organ is clearly visible. The buccal plate is 
rounded and pierced by the mouth opening 
FIG. 15. Crystallophrisson hancocki. Sta. 2839- 
Fig. 16. Crystallophrisson nitidulum var. pacifica. 
Characteristic spicules from body regions a, h, c, d, 
and other spines, labeled E, F, G, discussed in the text. 
near its dorsal edge. A glandular zone on the 
postabdomen and moderate incrustations of 
the latter are present. The subepidermal mus- 
cle layers are fairly strong, even in the region 
of the liver; in the prothorax the longitudinal 
layer splits up at once into numerous bundles. 
One finds several pairs of ventral, dorsal, and 
lateral retractors; the gill-retractor muscles are 
typical. The nervous system is characterized by 
a brain more clearly bilobed than usual, by a 
cerebrobuccal nerve split off the one common 
trunk shortly behind its origin, and by a supra- 
rectal ganglion surrounded by the pericardium. 
The digestive tract begins with a narrow 
fore-gut; its sphincter muscle is very strong. 
Buccal glands are observed only in front of it. 
Small ventral salivary glands with outlets on a 
very marked papilla; small dorsal ones behind 
