2 



BEITISH FOSSILS. 



and rather more depressed in relation to its length, than the typical 

 example. 



These differences are ecjually manifest in other specimens, — one 

 British and three Belgian, — in the cabinets of Dr. Wright and the 

 British Museum. In all the foreign specimens, when viewed from 

 above, the outline is notched posteriorly by the vent ; in the English 

 specimens this is less distinctly the case, the anal opening being 

 rather higher up, though not so high as in the Neocomian P. pygcea. 



These differences are so slight, and the materials so scanty, that 

 it will be better to treat them as indicating varieties only of one 

 species. 



Locality and Geological Position. — Mr. Pratt's specimen, and 

 another in the cabinet of Dr. Wright, were obtained from the 

 Chalk with quartz grains at Chard, Somersetshire. 



The foreign examples are from the Upper Geeen Sand (Tourtia) 

 of Tournay, Belgium. 



Plate YI. Fig. B. 



PYRINA OVULUM. 



Diagnosis. "P. ovata, injiata, siiperne dcpressa ; ambitu elliptico, basi 

 plancii margine valde tumldo; ore elongato obsolete decagorio ; facie postica 

 late sulcata ; ano elliptico, margini superiori proximo ; tuberculis numerosis^ 

 — (Desor). 



Synonyms. Nucleolites ovidum, Lamaeck, Anim. sans Vert., vol. iii. 

 37. GoLDFUSS, Petr., 1. p. ]38. t. xliii. f 2. Desmoulins, Ech., p. 356. 

 Pyrina ov., Agassiz (1847), Catal. Syst. Ectyp., p. 7. Desor, Monogr. 

 des Galei, p. 26. pi. 5. fig. 35-37. ; Morris's Catal., 2nd edit. p. 88. 



Locality and Geological Position. — Lower Chalk, Dorsetshire, 

 (sec. Morris's Catalogue.) 



Foreign Locality. — Chalk of St. Christophe and Tours, De- 

 partment Indre and Loire. 



Explanation of Plate VI. 



A. Pyrina Desmoulinsii, var. Prattii, 



Fig. 1. Upper view of Mr. Pratt's specimen. 

 Eig. 2. Side view. 

 Fig, 3. Under view, 

 rig. 4. Posterior end. 



Fig. 5. Tubercles of th.e upper surface, magnified. 

 Fig. 6. Do. and granules of the lower face. 



