MOLLUSCA. 



CEPHALOPODA. 



Ptiloteuthis, N. Gen. 



Elongate, subovate, very thin, anterior end broadly angulated, 

 no mid-rib ; slipper either minute or wanting. Surface marked 

 by numerous, irregular, small wrinkles, which radiate backwards 

 and outwards, partly from the anterior end and partly from an 

 imaginary median line. 



The present anomalous form cannot be confounded with any previously-described 

 genus. Beloteuthis and Phylloteuthis are narrow in front, and enlarge more or 

 less behind, and both have a mid-rib. Beloteuthis has straight radiating lines, all 

 diverging from the anterior end, and these are usually crossed by concentric lines 

 or undulations ; Phylloteuthis has a very narrow anterior end, a mid-rib, and well- 

 marked, straight, rigid, lateral stria? diverging at a broad angle from the mid-rib 

 alone. Coccoteuthis has a thick substance, and the surface is strongly pustulated. 

 Ptiloteuthis is very thin ; the lines or wrinkles, about twice as wide apart as the 

 thickness of the shell-substance, branch and anastomose among themselves, and 

 radiate in part from the anterior end, but in part diverge from a central line occu- 

 pying the proper position for a mid-rib, but only marked by the change in the 

 direction of the stria?. The anterior end terminates in an angle of about 60°, and 

 the slipper, if it ever existed, was so small as to be barely more than rudimentary. 



P. FOLIATUS, 11. S. 

 PL 19, Fig. 4. 



Shell thin, elongated, subovate ; anterior end angulated, the 

 sides rounding and rapidly widening, merging into the lateral 

 margins, which are broadly convex, nearly parallel ; posterior 

 M28 1 



