58 



BRITISH BELEMNITES. 



these occurred to me in Lower Lias (upper part) under HuntclifF, but they are very 

 much more acute (see B. elegans). 



Observations. Simpson makes no mention of the phragmocone or alveokis, but his 

 notes on the guard are ample. They are as follows : 



" B. Javis. Length of guard about five times its width, slightly depressed, smooth, 

 and regular ; apex generally compressed, sometimes with a flattened process ; the 

 surface in places toward the smaller end firmly and distinctly corrugated like leather, 

 probably by the impression of the mantle ; general length 3 or 4 inches. Some have 

 the apex striated." 



" B. trivialis. Subconical, moderately stout, expanding at the base, with numerous 

 fine strige at the rather obtuse apex ; general length 2 or 3 inches ; smaller specimens 

 approach the slender B. subtenuis, larger ones the more robust B. Icevis." 



The figures given in PI. X, fig. 23, were sketched from specimens in the Whitby 

 Museum ; the others (fig. 26) are in my cabinet, collected from the Saltwick shore 

 (1864). The striation is remarkable for distinctness and continuity over about a third 

 of the post-alveolar space ; but it can be traced further forward in short, discontinuous, 

 wavy ridges. 



Belemnites dorsalis, n. s. PI. X, fig. 24. 



Guard. Cylindroidal or slightly subhastate, tapering very gradually to a sharp apex ; 

 lateral grooves or flattenings on the middle and alveolar regions, not reaching to the 

 apex ; no ventral groove ; a short definite dorsal groove on the alveolar region only. 



Sections show the contour to be nearly circular, or a little compressed, or a little 

 depressed ; the axis excentric, even remarkably so in some examples. Greatest length, 

 including expansion of the guard, 22 inches ; greatest diameter behind the alveolar cavity, 

 i inch. 



Proportions. The diameter, v d, at the alveolar apex being taken at 100, the radius 

 V is from 30 to 40 (on an average about 35), and the radius d 60 to 70 (on an average 

 65) ; the axis about 700. 



Phragmocone. Insufficiently seen for accurate description. 



Locality. Saltwick, near Whitby, in Upper Lias {Phillips). Filey Cliffs, in drifted 

 Lias [Phillips). 



Observations. Thirteen specimens of diff'erent magnitudes, which I collected at 

 Saltwick in 1864, furnish the grounds for the determination of this curious and rare 

 form. I have seen it in no other collections, and have no knowledge of it beyond the 

 small, probably young, specimens here figured. The little deep slit or canal on the dorsal 

 aspect of the guard, is a circumstance unexampled in the Oolitic or Lias rocks. It 

 appears only on the retral part of the alveolar cavity, and ends in most specimens quite 



