:68 



BRITISH BELEMNITES. 



Belemnites quadricanaliculatus, Quenstedf. PI. XIII, fig. 35. 



Beference. Belemnites qiiadricanaliculatus, Quenstedt's ' Jura/ p. 285, pi. xli, fig. 17, 

 1857. 



Guard. Long conical, marked by four narrow grooves, from the apex to and 

 extending over the alveolar region. One of the grooves is dorsal, and in very good 

 specimens appears double (fig. 35 d') ; it is deepest on the alveolar region ; two are 

 dorso-lateral, one is ventral. The apex is somewhat blunt, the grooves reaching to it. 

 The surface unusually rough. 



Phragmocone. Unknown. Alveolar angle not measurable in either of the two 

 specimens placed before the author by the Geological Survey. 



Dimensions- Total length of specimen, 1-75 inch; greatest diameter, 0-33; axis of 

 guard, I'OO inch. 



Proportions. The ventro-dorsal diameter at the alveolar apex being 100, the axis of 

 the guard is 500, the cross diameter 96. 



Locality. Upper Lias Sands at Chidcock (Museum of the Geological Survey in 

 Jermyn Street, London). Upper Lias, Ilminster {Moore). 



Belemnites tubularis, Younff and Bird. PI. XIV, fig. 36. 



Beference. Belemnites tubularis, Young and Bird, ' Geol. of Yorkshire Coast,' 



p. 259, pi. xiv, fig. 6, 1822; Phillips's ' Geology 

 of Yorkshire, vol. i, p. 163, pi. xii, fig. 20, 

 1829. 



B. acuarius, Morris, 'Catal./ p. 300, 1854. 



Guard. Very elongate, slender, expanding over the alveolar region, uniformly 

 tapering or cyUndroidal in the post-alveolar region, greatly flattened in the apicial region, 

 ventral and dorso-lateral furrows on the flattened part. Surface striated unevenly, espe- 

 cially on the alveolar region. Proportion of the flattened part variable in different 

 specimens. A shght hollow or flat space often runs down the sides of the guard. Strong 

 parallel striaj near the apex. 



Transverse sections show an oval outline, with a nearly central axis in the young, a 

 nearly circular outline in the older. 



