302 A. M Verrill — North American Cephalopoda. 



Leachia Lesueur, 1821* {=Perothis (Escb.) Rathke, 1835), was also 

 based on an imperfect figure of a small Pacific Ocean squid, which 

 had likewise lost its tentacular arms. The only generic character 

 given was, as in Lamarck's case, the presence of only eight arms, — a 

 purelj^ fictitious character. The type of this genus was Leachia 

 cyclvra Les. It has a more elongated body, slender posteriorly, 

 with a more or less rounded caudal fin, the two sides of the fin com- 

 pletely united together and to the posterior end of the body. The 

 third pair of arms is much larger than the others. The anterior dor- 

 sal edge of the mantle is represented as^/y-ee, in all the figures, but, 

 according to D'Orbigny, there is an internal, dorsal commissure, and 

 also two lateral ones. The visceral anatomy of one species of this 

 group {L. guttata Grant), which D'Orbigny refers, probably cor- 

 rectly, f to the original L. cyclura., is pretty well known, and is widely 

 diflferent from that oiDesmotenthis (see PI. XXXIX, fig. 1), as well as 

 from that of Taonius, so far as the latter is known. 



There can be no doubt whatever as to the generic distinctness of 

 Leachia, if the anatomy be taken into account. (See the figures of 

 Grant and D'Orbigny.) 



Taonius Steenstrup, 1861, (type T. pavo). This differs from the 

 two preceding genera in its more elongated form, narrow caudal fin, 

 etc. From Leachia and Lesmoteuthis it differs in the form of its 

 pen. The dorsal edge of the mantle is represented and described 

 as free by D'Orbigny. The anatomical characters are not known. 



Desmoteuthis hyperborea VerriJi. 



Leachia hyperborea Steenstrup, Kougelige Banske Vidensk. Selsk. Skrifter, 5 r., 



iv, p. 200, 1856 (sap. copies, p. 16). 

 Taonius hyperboreus Steenst, Oversigt Kgl. Danske Vidensk. Selsk., Forhandliu- 

 ger, 1861, p. 83. 

 Verrill, Amer. Journ. Sci., xvii, p. 243, 1879; xix, p. 290, 1880. 

 Loligopsis hyperboreus Tryon, op. cit., p. 162 (inaccurate translation, after Steen- 

 strup). 

 Plate XXVII, figubes 1, 2. Plate XXXIX, figure ] (anatomy). 

 § . Body very long, tapering gradually backward, and ending in 

 a long, slender, acute tail ; mantle soft and flabby, with a capacious 

 branchial cavity; anterior dorsal edge advancing somewhat in the 



* Journal Philad. Acad., ii, p. 89, pi. 2. 



f Tryon criticizes this determination, because Lesueur '' describes and figures a 

 smooth species," while L. guttata has two rows of curious tubercles on the ventral side. 

 But as Lesueur only described a figure of the dorsal surface, his objection to this identi- 

 fication is absurd. 



