104 MR. OWEN'S DESCRIPTIONS OF 



chiate Cephalopods which have a pair of long peduncles superadded to the ordinary 

 eight arms, and to that family of Decapoda in which the rudimental shell is degraded 

 to the condition of a single horny style, lodged in the substance of the mantle in the 

 middle of its dorsal aspect. 



The principal external character which entitles Cranchia to rank as a genus distinct 

 from Loligo and Onychoteuthis, is the continuation of the mantle with the dorsal parietes 

 of the head, and a consequent interruption of its free anterior margin at that part : from 

 Sepioteuthis, Sepiola and Rossia, it differs generically (according to the circumstances 

 which modern zoologists have agreed to regard as of generic importance,) not only in 

 the proportions and position of the paUial fins, but in the structure and connexions of 

 the funnel ; and in some points of its anatomy, as will be afterwards described. With 

 respect to the first-named character I would however observe, that species in which the 

 pallial fins are short and terminal in position, and which present the same condition of 

 the internal rudimental shell, the same connections of the mantle, and armature of the 

 suckers, should not be broken up into genera in consequence of differences in the form 

 only of the fins, especially when unsupported by corresponding internal differences of 

 structure ; for when we compare together the different species of the uncinated Ca- 

 lamaries, which form the well-marked genus Onychoteuthis of Lichtenstein, we find that 

 scarcely two species agree in the precise contour of the fins ; and if we examine, with the 

 same view, the numerous members of the group Loligo, as it is now restricted, we shall 

 find several, as the Lol. piscatorum, Lapilaye ; Lol. Duvaucellii, D'Orhigny ; Lot. brevi- 

 pinna, Lesueur ; and especially the Lol. hrevis of De Blainville, which closely approximate 

 the Cranchia scahra in the rounded contour and dorsal position of the terminal fins ; so 

 that were it not for the difference in the connections of the anterior margin of the man- 

 tle, the latter Cephalopod, notwithstanding its singular form, could not be separated 

 generically from the Loligines on external characters alone. 



This condition of the mantle, however, has scarcely been sufficiently attended to in 

 the subsequent location of species in the genus Cranchia. In M. Ferussac's description of 

 one of the most remarkable of these recent additions, e. g. the Cranchia Bonelliana\ it is 

 to be regretted that no mention is made of the adhesion or otherwise of the mantle to the 

 posterior part of the head. The same doubts apply to the claims of the Cranchia car- 

 dioptera of Peron, and the Cranchia minima of Ferussac, to rank in the genus in which 

 they have been placed : in the figures given of them by Ferussac, the anterior margin 

 of the mantle appears to be free on the dorsal aspect, as in Loligo. In justice, however, 

 to the lamented zoologist who first described the Cranchia Bonelliana, and to whom the 

 scientific world is indebted for a most splendid monograph on Cephalopoda, now in pro- 

 gress of publication, it must be observed, that the limited nature of the observations 

 on the characters of Cranchia, and the imperfection of the specimen upon which Dr. Leach 



' Annates des Sciences Naturelles, torn. iii. (1835) p. 339. 



