BELEMNITES OF THE LIAS [OOLITE]. 45 



numerous, distant from each other about jth of the diameter. Siphuncle marginal, monili- 

 form, quite free from the external layer of the conotheca, and completely bordered by its 

 own shell (a single plate?). The flanges are short. 



Locality. In the Inferior Oolite of Dundry Hill, with Ammonites Humphrey sianus 

 {Bristol Museum). In the same beds at Wotton-under-Edge, Procester Hill, Cam Down, 

 Bridport [PJdllips). Near Cheltenham {Buckman). 



Observations. The specimens figured are, without doubt, to be referred to the species 

 first separated from the ordinary breviformis by Oppel. I have seen foreign examples. 

 The figures given by Quenstedt show some degree of lateral compression, but I cannot 

 doubt the identity of his species with ours from Gloucestershire and Somersetshire, 

 D'Orbigny's figures ('Terr. Jur.,'' ph ix, figs. 1 and 3), which are said to be from the 

 Upper Lias, agree with our specimens well enough, but the transverse section of the 

 phragmocone (fig. 4) is so remarkably oval that, if not due to compression, there must be 

 some mistake. The phragmocone is represented in fig. 2 of the same plate, as quite 

 straight on the ventral side. 



Belemnites insculptus, n. s. PL V, figs. 12, 13. 



Reference. (I can find no satisfactory figure or description of this Belemntte.) 



Guard. Short, conoidal, tapering rapidly to a produced, submucronate, somewhat 

 recurved summit, from which two broad, shallow, lateral furrows proceed, growing less 

 distinct over the alveolar region. 



Transverse sections show the outline to be nearly circular, but flattened more or less 

 on the sides ; the axis very excentric towards the ventral face, and arched. Sometimes 

 the dorsal aspect is widest, sometimes the ventral ; it is flattened sometimes on the ventral 

 face, as in B. ventroplanus of Voltz. 



A section taken lengthways shows the axis to be excentric, and arched in accordance 

 with the reflected apex. 



Greatest length observed (edge of aperture very thin), 3i inches ; greatest breadth, less 

 than 1 inch. 



Proportions. The diameter at the apex of the phragmocone being 100, the ventral 

 radius is 43, the dorsal 58, the axis 120. 



Phragmocone. Very oblique, arched, with a circular cross section. Conotheca con- 

 centrically undulated on the ventral face ; concamerations numerous ; angle m. 28°. 

 Septal diameter eight or even nine times the depth. Axis of phragmocone traced to twice 

 the length of the axis of the guard. Fifty septa in three quarters of an inch from the 

 apex of the phragmocone. 



Locality. Inferior Oolite, with Ammonites Humphrey sianuSyTixmdirf [Sanders), ^g. 12. 



