144 PEOP. OWEN ON NEW AND EAEE CEPHALOPODA'. 



Genus Ommastrephes, d'Orbigny '. 

 Species Ommastrephes ensifee, Ow. (Plate XXVIII.) • 



In the family of Squids (Loliginidse), 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 (PI. XXVIII. fig. 1, o), with which is associated the depression 

 in the integument anterior to the eye, termed " lacrymal sinus," I. 



In this group the species Ommastrephes hartrainii, Le Sueur', and 0. oualaniensis, 

 d'Orbigny *, come nearest to 0. 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 a) 

 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 b), 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 " Xiphoteu- 

 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. 

 Length of body 15 6 



„ of head to interspace of dorsal arms i . . 3 7 



„ of arms i 8 9 



„ of arms 2 11 



of arms 3 12 



of arms 4 96 



„ of tentacles (outstretched) 210 



„ of attached base of fin 6 6 



Breadth of the pair of fins 12 6 



„ of body in advance of fins 4 



„ of fore end of body 5 



„ of head across the eyes 4 



Breadth, extreme, of arm 2 16 



„ „ of arm 3 3 



Total length from apex of body to end of outstretched tentacles 3 feet. 



' Histoire Naturelle des Cephalopodes Acetabulifuros, 4to, 1835-1848, p. 341. 



° In op. cit. described as the " appareil de resiatance," p. 341. 



' Journal of the Academy of Natural Sciences, Philadelphia, for 1821, p. 90, pi. vii. 



• Op. cit. p. 351, ' Ommastrephes,' pi. i. ' Calmars,' pi. iii. 



' ii<poi, sword ; revQis, squid. 



