608 HOLLUSCA 



DIVISION 2. SEPIOPHORA. 



Shell consists of a highly modified, calcareous phragmocone with air 

 chambers but without siphuncle, and with a rudimentary rostrum: 1 

 family. 



FAMILY SEPIIDAE. 



Body oval ; fins narrow, as long as the body, generally united behind ; 

 suckers generally in 4 rows; eye with cornea; fourth arm on left heeto- 

 cotylised: 33 species; cosmopolitan. 



SEPIA L. Cuttle fish. Shell (cuttle bone) cal- 

 careous, large, broad, very thick in front, concave in- 

 ternally behind; it was formerly used in medicine as 

 an antacid: 30 species; 10 fossil species. 



A. officinalis L. (Fig. 955). Common sepia. Length 

 of body 20 cm.; color brownish with white spots and 

 stripes, and with violet fins: Europe; used for food in 

 the Mediterranean. 



Fig. 955 

 Sepia offlcina- DIVISION 3. CHONDROPHOBA. 



Us (Leunis). 



arm; 2, fin. Squids. Shell (pen) a straight, chitinous plate, 



grooved towards the upper side and representing the 

 proostracon alone, sometimes with a conical rudiment of the phrag- 

 mocone at the aboral end ; fins usually rhombic or more or less triangular 

 and usually at the aboral end of the body: 8 families. 

 Key to the families of Chondrophora here described: 



o t Fins not at the end of the body 1. SEPIOLIDAE 



a a Fins at the end "of the body. 

 &! Siphon with a valve. 

 d Tentacular arms without hooks. 



dj Eyes with a cornea 2. LOLIGINIDAE 



d a Eyes naked, without cornea 3. OMMASTREPHIDAE 



c a Tentacular arms armed with hooks 4. ONYCHOTEUTHIDAE 



6 3 Siphon without a valve 5. CBANCHIIDAE 



FAMILY 1. SEPIOLIDAE. 



Body short and wide; fins large, rounded, with a narrow base and 

 near the middle of the body; tentacular arms retractile; eyes with a 

 cornea; pen (shell) about half as long as the body and in its hinder half, 

 or absent: 17 species. 



1. STOLOTEUTHIS Verrill. Body short, globose; head very large; 

 arms united together by a broad web; tentacular arms with 8 or more 

 rows of very small stalked suckers; upper arms hectocotylized ; mantle 

 united with head on back; pen absent: 1 species on the Atlantic coast. 



