392 Prof. T. R. Jones on the 



yet the following features are distinguishable :— The dorsal 

 margin is nearly straight in its middle third, and curves off 

 rapidly at the ends. The ventral margin is rounded, but 

 most convex in the posterior third. The extremities are 

 rounded ; the anterior end narrower than the other. The 

 dorsal sulcus is strongly marked, curved forwards, and in- 

 denting nearly three fourths of the width of the valve. An- 

 terior to the furrow, and within its curve, the surface of the 

 valve is raised up into a low cone or tubercle. In the speci- 

 men from Bow Bridge the valves are much flattened by 

 pressure. 



Another specimen * of the same species comes from Whit- 

 cliff, Ludlow, near the place of that last mentioned, and in 

 the same kind of shaly mudstone of the Upper-Ludlow 

 series. It is also preserved in the Museum of Practical 

 Geology, Jermyn Street. 



Specimens closely resembling the foregoing were collected 

 about or before 1866 by Messrs. Haswell, Brown, and Hen- 

 derson, of Edinburgh, in the Upper-Silurian mudstone of the 

 Pentland Hills. 



A very fine and well-preserved, though slightly crushed, 

 specimen of E. tnherosa f has been obtained from the Upper 

 Wenlockshaleof Dudley by Henry Johnson, Esq., F.G.S. &c., 

 of that place. The material of its valves is preserved, brown 

 and smooth, somewhat crumpled by pressure. The two valves 

 lie side by side in a bluish-grey limestone ; the dorsal edge of 

 the left valve has been slightly pushed over that of the other 

 valve. They retain some of their original convexity ; but 

 the tubercle in front of the curved sulcus is depressed and 

 pushed backward. Length of valve yV? height y^ inch. 



The Australian specimens of Entomis tuberosa referred to 

 in the Mem. Geol. Surv. Scotland (32), 1861, p. 137, and 

 Ann. & Mag. Nat. Hist. June 1873, p. 415, were collected by 

 the late Count P. E. de StrzeleckiJ at Yarralumla, Queen- 



* Loc. cit. (14). _ 



t This fine specimen, together with some rare, well-preserved, and 

 large Eutomids from the Lower-Ludlow Shale of Sedgley, has been 

 kindly lent to me by Mr. Henrj- Johnson, of Dudley ; and I have been 

 able to get one of the latter figured in time for this communication. He 

 has also been so good as to communicate others, collected by Mr. C. 

 Beale from the same shale. 



X They are not mentioned in the Count's book ' Pliysical Description 

 of New South Wales and Van Diemen's Land,' 8vo, London, 1845. The 

 Rev. W. B. Clarke refers to these mudstones of Yarralumla, with Encri- 

 nurus and Ccdymene, in his " Remarks on the Sedimentary Formations of 

 New South Wales,'- in the Appendix to the ' Catalogue of Natural and 

 Industrial Products of New South Wales,' &c,, 1867, p. 69. 



