On the Homologies of the Cephalopoda. 303 



Leiocephalus aculeatus, sp. n. 



Two lateral carina? along the upper edge of the sides as 

 well as the median dorsal one. Supraorbitals very broad, as 

 in L. tridescenS) Gthr. 



Head as high as broad. Nostril posteriorly in an elongate 

 nasal shield. Scales on the top of the muzzle numerous, 

 polygonal, becoming larger towards the frontal region, where 

 they pass into the two series of large interorbital plates, which 

 are closely in contact. Three occipital plates — two rather large 

 anterior, and one small posterior ; two parietals on each side, 

 the posterior one being very large. Orbital canthus sharp. 

 A single series of very broad supraorbitals bordered with some 

 small scales on each side. Only one elongate scale on the 

 canthus between the upper angle of the orbit and the nostril, 

 there being two such scales in L. iridescens. Upper labials 

 four, narrow, elongate ; a row of eight small scales above 

 them ; two rows of frenals, with an elongate infraocular scale. 

 Ear-opening about half as large as the eye. The scales are 

 everywhere keeled, sharp and dagger- like, with projecting 

 points. A median dorsal crest of erect triangular scales ex- 

 tending on the tail ; a weaker lateral one on each side of the 

 back. Tail long, compressed, nearly thrice the length of the 

 body. 



Bronzed green, brownish on the sides, with vertical streaks. 

 A white stripe from the ear to the fore limb, and another 

 superiorly from the ear as far as the shoulder ; another white 

 stripe descending from the lateral carina to the fore limb. 



millim. 



Distance of snout from eye 10 



„ „ ear 23 



„ „ fore limb 45 



„ „ vent 100 



Length of fore limb 50 



„ third and fourth front toe 16 



„ hind limb 85 



„ fourth hind toe 25 



Five specimens of the above described species were collected 

 by Mr. Roff ; they are from Moyobamba, Peru. 



XXXIV. — On the Homologies of the Cephalopoda. By J. F. 

 Blake, M.A., Lecturer on Comparative Anatomy at 

 Charing-Cross Hospital. 



There are two points of interest in the relations of the Ce- 

 phalopoda which cannot yet be said to be settled. The first 



