316 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



gladius being preserved at its anterior end, at about its mid-length, and 

 at its posterior end respectively. As a whole the gladius is acutely- 

 triangular, the apical angle being about 11°, and the base, which is 

 anterior, about 53 mm. It is traversed by very fine somewhat 

 irregularly-placed longitudinal strise. There is a well-marked median 

 area, which at the anterior end of the pen attains a widtli of about 

 14 mm., and a lateral area on each side. Each lateral portion bears 

 a sligbtly-thickened area which extends longitudinally, and terminates 

 anteriorly in a rounded process (m) about 9 mm. wide, and of a brownish 

 colour. Between these two processes the anterior boundary of the 

 gladius is obscure ; it may have been projected forward for about 

 12 mm., so as to form a broad, fully-convex projection, about 21 mm. 

 broad, since the surface of this projection seems to be continuous with 

 tiiat of the pen. Posteriorly, at about 55 mm. from the end of the 

 lateral process, the pen expaiuls rather suddenly, though slightly, but 

 soon resumes its original direction, and at about its mid-length it 

 again gradually expands througli about a fourth of its length, then 

 gradually contracting it attains, at about 55 mm. from the posterior 

 end, a width of about 25 mm. The rest of the pen has a rhomboidal 

 form, its greatest width, corresponding to the shorter axis of the 

 rhomboid, being about 43 mm., the lateral angles of tlie rhomboid 

 occupying the median line of each fin, for which nndoubtedly this 

 portion of the pen formed a support. 



Dimensions. — Assuming that the stellate mass (Jc) of calcite in the 

 head represents the cavity of the buccal mass, and that the posterior 

 end of the body (excluding some spinous processes) is about 332 mm. 

 from this point, the dimensions of the specimen, so far as ascertain- 

 able, are as follows : — 



mm. 

 From posterior end of body to mantle-margin . . 290 



From posterior end of body to anterior end of lateral 

 process of pen . . . . . . .278 



Breadth of body (at anterior end) . . .55 



Breadth of body at widest part, which is at about 



105 mm. from the anterior end .... 75 



Width of pen at anterior end of lateral process . . 52 



Width of pen at about 70 mm. posterior to the anterior 

 end of lateral processes . ..... 53 



Width of head probably about ..... 40 



From anterior end of pen to centre of buccal mass . 42 

 From the centre of the buccal mass the arms can be 

 certainly traced for a length of . . . .58 



The whole length of the animal with its arms must have been 

 490mm. (about 1 ft. I^'in.). 



When Dr. A. Wagner (6, p. 784) founded the genus Plesiofeutliis, 

 he recognized two species, viz. Plesioteuthis prisca and P. acuta. 



Plesioteutkis prisca was originally described by Kiippell (5, p. 8, 

 pi. iii, fig. 1) as a Loligo in 1829, and quite a number of forms which 

 were subsequently described by Miinster and by D'Orbigny were 



