Vol. 62,] L1ASSIC DENTALIID^E. 581 



are provisionally regarded as correctly identified with D. gigcniteum, 

 Phillips. 



Except in Yorkshire, this scaphopod does not appear to be at all 

 common ; indeed, I have examined specimens only from that county. 

 Dentalium giganteum, I think, lived only during the margaritati 

 hemera. 



Dextalium hexagonale, sp. nov. (PI. XLY, figs. 1 «-l c.) 



T.l. Gasworks, Gloucester. 

 H. Sinemurian-Pliensbachian. 



i]. [oxtjnoti-armati.] 

 Colin. L. Richardson. 



Diagnosis. — Shell small, curved; transverse section circular 

 interiorly, hexagonal exteriorly ; surface-ornamentation consisting 

 of numerous, closely-set, regular, fine transverse lineaa. Dorsal side 

 broad, very slightly convex towards the anterior end. The sides 

 converge towards the ventral surface, but while slightly inflated 

 near their junction with the dorsal side, give rise to sharp angular 

 keels at their junction with the ventral side, which also becomes 

 slightly convex near the anterior end. 



Remarks. — The transverse section of this scaphopod is the 

 characteristic feature, and easily distinguishes it from all other 

 Liassic forms. In the gerontic stage, however, the section of the 

 anterior end is very similar to that of D. sub trig onale in the same 

 stage : but the hexagonal form is otherwise a very constant character. 

 The records are : — armati- Jamesoni, railway-cutting, Toddington, 

 near Winchcomb (near Cheltenham) ; armati (and Jamesoni?), rail- 

 way-cutting, near Aston Magna, near Moreton-in-the-Marsh (Slatter 

 Colin., Nat. Hist. Mus., identified by Slatter with B. angulatum, 

 J. Buckman) ; oseynoti-armati, Gasworks, Gloucester. 



Dentalium liassicum, Moore. (PI. XLV, figs. 6 a-6 c.) 



T.d. 1865-67. Proc. Somerset Arch. & Nat, Hist. Soc. vol. xiii, p. 202. 

 T.f. Ibid. pi. v, fig. 24. 

 T.l. Camerton [near Kadstock, Somerset]. 

 H. ' Middle Lias.' [Pliensbachian.] 

 rj. [armati.] 

 Colin. Moore, Bath Museum. 



Dentalium liassicum, Tate, 1876, ' The Yorkshire Lias ' p. 333 ; Walford. 1879, 

 Proc. Warwickshire Nat. & Arch. F. C. p. 18; Thompson, 1888-89, 'Middle 

 Lias of Northamptonshire ' p. 29. 



Protolog. — 'Shell slightly incurved and tapering, thick, outer 

 surface ornamented with about twenty -four longitudinal ridges at 

 rather irregular distances, within which are numerous slightly- 

 oblique annular lines of growth : aperture circular.' 



Length of holotype (fragment), between 5 & 6 millimetres. 



lie marks. — Of this rave Dentalium, which is easily distinguished 

 from the other Jurassic species by its longitudinal ornament, Charles 

 Moore possessed but one specimen, ' which has lost its apical 

 portion.' This is the specimen in the Bath Museum. The ' annular 



