382 



OCTOPODA 



CHAP. 



tions of the same. In front of the cephalic cartilage occurs a 

 piece like an inverted T, which supports the base of the anterior 

 arms. The Decapoda have also a ' nuchal ' cartilage, connecting 

 the head with the anterior dorsal portion of the mantle, while 

 cartilaginous knobs on the ventral mantle button into correspond- 

 ing sockets on the funnel. 



Sub-order I. — Octopoda. — Body round or bag-like, generally 



Fig. 241. — Cirrhoteuthis magna Hoyle, S. Atlantic. Two of the left arms and their 

 web have been removed: /, funnel; Ji,fi, fins; m, mouth. (After Hoyle, x ^\j.) 



without fins, arms eight, suckers fleshy, usually sessile, oviducts 

 paired, no nidamental glands, shell absent. 



Fam. 1. Cirrhoteuthidae. — Body with two prominent fins ; 

 arms in great part united by a web; one row of small suckers, 

 with cirrhi on each side. — Atlantic and Pacific Oceans, deep 

 water (Fig. 241). 



Fam. 2. Ampldtretidae. — Body gelatinous, mantle fused with 



