144 PROF. OWEN ON NEW AND RARE CEPHALOPODA. 
Genus OMMASTREPHES, d’Orbigny °. 
Species OMMASTREPHES ENSIFER, Ow. (Plate XXVIII.) 
In the family of Squids (Loliginide), to which the present specimen belongs, the group 
differentiated by d’Orbigny under the generic name above given includes it by the 
form of the lateral cartilages on the inner surface of the mantle and of the cavities on 
the sides of the base of the funnel adapted thereto’, by the absence of eyelids, and by 
the orifice of the eyeball (Pl. XXVIII. fig. 1, 0), with which is associated the depression 
in the integument anterior to the eye, termed “ lacrymal sinus,” /. 
In this group the species Ommastrephes bartramii, Le Sueur*, and O. oualaniensis, 
d’Orbigny*, come nearest to O. ensifer in the development of the tegument forming 
the ventral margin of the acetabuliferous tract of the second (ib. 2 a) and third (ib. 3 @) 
arms. But such development is much exceeded, especially in the third arm, in 0. 
ensifer; it is moreover associated with a production of the integument of the 
outer ridge or surface of that arm, in a subangular form (ib. 3 4), which expansion, 
combined with that of the acetabular velum (a), gives to the third arm the shape of an 
eastern scymitar, whence the specific name proposed for the present species. Should 
this be deemed a character of subgeneric value, I would propose the term “ Xtphoteu- 
this” ® for the present and other species that may be found to possess it. 
The following are dimensions of the individual on which the species is founded :— 
in. lin. 
Lene ol bodys, Sienath. tive wits cas ldo gh 
», of head to interspace of dorsalarms1 . . 3 7 
i; SMO LMATIIS oly Mean ty: alter 1-11 et Re RAeTs Aa CIES, 
Se Ofarms 2 ae PA bie edi ene ate he 
GE aia Seance alec’ ri) Tas aeeescy Flzaeg® 
OL rRIiS Hees ARE id tir Ukerne ey debe 
»» of tentacles (outstretched) . . . . . 21 0 
5, of attached base of fin . aMesiaaie tathelome6 
Breadth .of the pairior tities i desist; )< viel soreen fe leone 
»» Of body inadvance of fins. . . ... 4 O 
», of fore end of body . 5 (0 
», of head across the eyes. 4 0 
Breadth, extreme, of arm 2 1 6 
= = OATS /iccokts See ow 0 
Total length from apex of body to end of outstretched tentacles 3 feet. 
' Histoire Naturelle des Céphalopodes Acétabuliféres, 4to, 1835-1848, p. 341. 
* In op. cit. described as the “‘ appareil de résistance,” p. 341. 
* Journal of the Academy of Natural Sciences, Philadelphia, for 1821, p. 90, pl. vii. 
* Op. cit. p. 351, ‘ Ommastrephes,’ pl. i. * Calmars,’ pl. iii. 
* Eipos, sword; revOis, squid. 
