OCTOPODA. 445 



project itself for long distances from the water and is not unfrequently found 

 on the decks of ships ; Ctenopteryx Appellof ; Chaunoteuthis Appellof ; Arclii- 

 teuthis Steenstrup, includes the largest Cephalopoda known. 



The Thysanoteuthidae are allied here. 



Fam. 2. Onychoteuthidae. Tentacular arms long ; suckers with, hooks. 

 Onychoteuthis Lichtenstein, the uncinated calamary, with hooks on the tentacular 

 arms, and a small group of suckers at the base of each club, enabling them to 

 act like forceps. Enoploteuthis d'Orb., armed calamary, with hooks on all the 

 arms (as well as suckers). Verania Krohn, tentacular arms atrophied in the 

 adult. 



The Gonatidae (Gonatus Gray) are allied here. 



Fam. 3. Chiroteuthidae. Tentacular arms very long, pen expanded at each 

 end. Chiroteuthis d'Orb. ; Histioteuthis d'Orb. ; Histiopsis Hoyle ; Calliteuthis 

 Verr.; Doratopsis Rochebrune. 



Fam. 4. Cranchiidae. Arms very short ; fins terminal, small ; eyes pro- 

 jecting. Loligopsis Lam. ; Histioteuthis d'Orb. ; Cranchia Leach ; Leachia Les. ;. 

 Taonius Steenstrup. 



The above-named four families constitute the Oegopsida, which are character- 

 ized by their pelagic habit, by the possession of a perforated cornea, and by the 

 presence of two oviducts. 



Fam. 5. Spirulidae. Female with a single oviduct (right) and two nida- 

 mental glands. Shell spiral, coils not touching, multilocular, with internal 

 siphon, partly internal, enclosed in two lobes of the mantle ; it is coiled 

 ventrally (Fig. 339), i.e. in the opposite way to that of Nautilus. Without 

 rostrum and proostracum. Spirula Lam.; &'. Peronii Lam., Pacific Ocean, 

 probably abyssal. 



Fam. 6. Belemnitidae. Arms with hooks, shell multilocular, straight, 

 probably internal, with rostrum and proostracum. Extinct. Lias to Cretaceous. 

 Belemnites Breyn. 



Fam. 7. Sepiolidae. Body short, rounded dorsally ; fins rounded, inserted 

 somewhat on anterior surface of visceral sac, midway. Sepiola Leach ; JKossia 

 Owen ; Stoloteuthis Verrill ; Inioteuthis Verrill. 



The Idiosepiidae (Idiosepius Steenstrup smallest cephalopod known) and 

 Sepiadariidae are allied here. 



Fam. 8. Loliginidae. Body elongated, conical ; fins terminal, rhombic ; 

 pen lanceolate. Loligo Lam. , calamary ; the pens increase in number with age ;. 

 several are found in old specimens (Owen, in Todd's Cyclopaedia of Anatomy and 

 Physiology, vol. i. p. 546). Sepiotcuthis Blainville ; Loliolus Steenstrup. 



Fam. 9. Sepiidae. Body flattened, broad ; fins narrow, elongated, shell 

 internal calcareous. Sepia L., cuttle-fish. 



The families Sepiolidae, Loliginidae, Sepiidae constitute the group Myopsida 

 characterized by their unperforated cornea and single oviduct (left). 



Sub-order 2. OCTOPODA. 



With eight arms, without tentacular arms. The suckers are sessile. Eyes 

 relatively small, with sphincter-like lid. Shell absent. The heart does not 

 project into coelom. Oviduct paired. Nidamental glands absent. Funnel 

 without valve. Mantle without sucker-like apparatus for closing mantle- 

 opening. 



