180 OMMASTREPHES. 



O. Sloanii, Gra3-. 



Body cylindrical, rather tapering behind ; fins rhombic, rather 

 more than one-third the length of the body ; arms compressed, 

 the third pair acutel}- finned, with a narrow rayed membrane on 

 the inner edge of the ventral side ; tentacles slightly keeled 

 externally, base half naked ; cups of lower part small, in two 

 rows, of middle in four rows, the seventh pair of the central 

 series largest (rings with distant teeth all round), of the apical 

 part in three or four rows. 



New Zealand ; Indian 0, 



Described from specimens in Mus. Brit., and not figured. The 

 description does not indicate any great ditierence from the two 

 preceding species. 



•)■ f f Second and third pairs of arms icith a broad, membranaceous fin or 



icing on the inner edge of the ventral side, supported by radiating fleshy 



rays arising from the base of the cups. Cups in ttco distinct 



roios ; ventral part of the mantle free from the liead. 



0. Bartramii, Lesueur. PI. 80, figs, 3(>1, 3(i2. 



Body elongate, cylindrical, acuminate posteriorly ; fins dilated, 

 rhomboidal, the angles acute ; head short ; arms short, biangu- 

 lated or triangulated dorsalh' ; tentacles large, short, biangulated. 

 Shell ver}^ narrow, the extremity enlarged. 



Total length, 10 inches, length of body, (5 inches. 



The chromatophores are aggregated into a dark dorsal band. 

 West Indies ; Oulf Stream ; Cape of Oood Hope? 



t t t t Second and third pairs of arms loiih a broad membranaceous fin on 



the inner edge of the ventral side, supported by radiating fl,eshy rays ; 



Clips compressed so as to be generally in a single series. 



O. OuALANiENSis, Lcsson. PI. 81, fig. 3(58. 



Body elongated, cylindrical ; fins terminal, broad, transverse ; 

 arms short, unequal, furnished with one row of cups, tentacles 

 much longer than the arms. Shell elongate, narrow. 



Total length about (> inches. 



Indian Ocean ; Cape of Good Hope ; Pacific Ocean. 



O. Tryonii, Gabb. PL 81, figs. 3T2. 373. 



Body elongated, cylindrical, tapering to ;i point behind ; fins 

 transversely rhomboidal, between one-third and one-fourth the 

 length of the body ; arms short, compressed, robust, compara- 



