XIII 



DECAPODA 



391 



teuthis and Ancistroteuthis^ the sessile arms have acetabula only, 

 in Gonatus and Abralia they have hooks as well, while in 

 Verania^ Ancistrochirus and Enoploteuthis, the sessile arms have 

 hooks only. The number of rows of hooks or acetabula varies 

 with the different genera. 



Fam. 7. Chiroteuthidae. — Head nearly as large as the body; 

 fins terminal, tentacular arms very long, 

 sessile arms slightly webbed, acetabula 

 denticulated ; mantle-supports consist- 

 ing of cartilaginous ridges on the 

 mantle, which fit into corresponding 

 depressions on the funnel, gladius ex- 

 panded at each end. — Atlantic Ocean. 



The six dorsal arms in Histioteuthis 

 are united by a broad web, while in 

 Histiopsis the web only reaches half 

 way up the arm. In Ckiroteuthis the 

 tentacular arms have scattered sessile 

 suckers throughout their whole length, 

 and four rows of very long peduncu- 

 late suckers on the clubs. 



Fam. 8. CrancMidae. — Head small, 

 body rounded, barrel-shaped, fins termi- 

 nal, eyes often very large, sessile arms 

 short, tentacular arms long, thread-like. 

 — World-wide. 



Cranchia proper has the tentacular 

 clubs finned, with eight rows of suck- 

 ers, body sometimes covered with warty 

 tubercles. Loligopsis has a very atten- 

 uated body, with fins terminally united ; 

 some species are spotted with colour, 

 or have rows of tubercles on the ventral 

 side. Taonius (Fig. 251) is doubtfully 

 distinct from Loligopsis. 



Fig. 2h\.— Taonius hyperboreus 

 Stp., N. Atlantic: e, e, eyes; 

 /, /, fins ; t, t, tentacular 

 arms. (After Hoyle, x ^.) 



Order Tetrabranchiata 



Cephalopoda with four branchiae and four kidneys ; animal 

 inhabiting the last chamber of an external multilocular shell ; 



