102 Mr, li, Etheridge on Carhoniferous Lamellihranchiata. 



portion of the ventral margin straigliter, and the anal angle 

 sharper than in Prof. McCoy's figure ; it is also a smaller 

 sliell. Notwithstanding these slight discrepancies, Mr. Shar- 

 man, of the Museum of Practical Geology, to whom the sliell 

 was submitted, agrees with me in believing this to be a variety 

 of L.fragilis. As in the redefined diagnosis of Leptodomus^ 

 the present shell did not, I think, gape anteriorly and pos- 

 teriorly, and there is no sulcus in the posterior slope, neither 

 does the dorsal margin appear to be inflected or bear an up- 

 ward curvature. 



Loc. and Horizon. Obtained by Mr. A. Patton from the 

 Calderwood Cement-stone (?Lingula Limestone of Carluke), 

 at the Kirktonholm Cement Works, East Kilbride, Lanark- 

 shire ; Lower Carboniferous Limestone group. 



Leptodomus ? clavatus, sp. nov. ? PI. IV. figs. 9 & 10. 



8j). char. Clavate, arcuated, very inequilateral, and gib- 

 bous in the umbonal region. Anterior side short, convex, its 

 margin rounded ; posterior side much more compressed, trans- 

 versely elongated, somewhat recurved, and truncated obliquely, 

 with an obtusely rounded ridge from the umbones to the pos- 

 terior ventral angle ; posterior slope a little concave (?) , and 

 divided by a sulcus or groove from behind the beaks back- 

 wards to the posterior margin. Umbones large, prominent ; 

 beaks terminal (?). Surface ornamented with wrinkles parallel 

 to the margins. Internal characters ? Shell thin. 



Ohs. The smaller of the two figures (fig. 10) is a small 

 example of a shell which occurs in some abundance at two 

 localities in this neighbourhood, but, as a rule, in a crushed 

 and mutilated condition. I believe it to be distinct from Lep- 

 todomus costellatus^ M'Coy* ; and the profusion with which it 

 occurs, especially at one of the two localities, necessitates a 

 name being given to it. From the species just mentioned it 

 differs in its more transversely elongated form, absence of any 

 sinus in the ventral margin near the anterior end, more sharply 

 defined posterior ventral angle, and less height of the posterior 

 end. Fig. 9 I believe to be the same shell, but from another 

 locality. In seme specimens the posterior end is almost 

 square, in others the obliquity is considerable ; this may arise, 

 perhaps, in some degree from pressure. Crushed s])ccimens 

 at first sight bear some resemblance to Lntraria elongataj 

 M'Coyf. 



Loc. and Horizon. Shale above the Craigleith sandstone, 



* Brit. Pal. Foss. p. 508, t. 3 F. f. 5. 



t Syii. Carb. Foss. Ireland, 1844, p. 52, t. 8. f. 3. 



