th of the tentacular arms. _Doratopsis_, body very
long and slender with aboral spine, dorsal arms very short.
_Histioteuthis_, six dorsal arms united by membrane, photogenous
organs present. _Histiopsis_, membrane of dorsal arms only half-way
up the arms, photogenous organs present. _Calliteuthis_, no brachial
membrane, photogenous organs present. _Grimalditeuthis_, two fins on
each bide, no tentacular arms.

Fam. 11. _Cranchiidae_. Eight normal arms, very short; eyes
prominent; fins small and terminal. _Cranchia_, body short,
purse-shaped, normal arms short, fins entirely aboral. _Loligopsis_,
body elongated, conical, tentacular arms slender. _Leachia_,
tentacular arms absent, funnel without a valve. _Taonius_, body
elongated, normal arms, rather short, eyes pedunculated.

[Illustration: FIG. 38.--Octopodous Cephalopods.

A, _Pinnoctopus cordiformis_, Quoy and Gain (from New Zealand).

B, _Tremoctopus violaceus_, Ver. (from the Mediterranean).

C, _Cranchia scabra_, Owen (from the Atlantic Ocean; one of the
Decapoda).

D, _Cirrhoteuthis Mulleri_, Esch. (from the Greenland coast).]

Tribe 2. _Myopsida_.--No aperture in the cornea. Left oviduct only
developed in female. Internal shell without a distinct phragmacone,
calcified or simply chitinous.

Fam. 1. _Sepiidae_. Body wide and flat; fins narrow, extending the
whole length of the body; shell calcareous and laminated.
_Belosepia_, a rudiment of rostrum and phragmacone present in shell,
Eocene. _Sepia_, shell with a rostrum, British. _Sepiella_, shell
without a rostrum.

Fam. 2. _Sepiolidae_. Body short, rounded at the aboral end; fins
rounded, inserted in middle of body-length; shell chitinous, small
or absent. _Sepiola_, head united to mantle dorsally, British.
_Rossia_, head not united to mantle, British. _Stoloteuthis_ and
_Inioteuthis_, without shell. _Heteroteuthis. Euprymna._

Fam. 3. _Idiosepiidae_. Body elongated, with rudimentary terminal
fins; internal shell almost lost. _Idiosepius_, 1.5 cm. long, Indian
Ocean.

Fam. 4. _Sepiadariidae_. Body short; mantle united to head dorsally;
no shell. _Sepiadarium_, Pacific Ocean. _Sepioloidea_, Australian.

Fam. 5. _Loliginidae_. Body elongated and conical; fins extending
forward beyond the middle of body-length; shell chitinous, well
developed. _Loligo_, fin