526 EEV. G. F. WHIDBOENE ON SOME EOSSILS 



divided by the raised margins of the shell. Surface covered with about 

 70 low, close, distract, and very rounded rays, crossed by nume- 

 rous concentric regular lines which form frills with the rays, and 

 give the shell a kind of tesselated appearance. Test very thick. 



Dimensions. 10 lines long, 11 wide. 



Two specimens in the British Museum from Dundry, and one in 

 my collection from the ParJcinsoni-zona of Bradford Abbas. There 

 are similar shells from the same locality at Jermyn Street. 



This form much resembles Sphcera madridi, D'Arch., except in its 

 ornamentation and its more dilate margins. Though Morris and 

 Lycett, after examining specimens of all ages, described that species 

 as smooth, there must remain some doubt whether the present shell 

 is more than an extreme variety of it. 



Sph^ea ceassicosta, D'Orb., sp. Plate XYI. figs. 16, 16 a. 



1849. Corois crassicosta, D'Orb., Prodr. sect. 11, no. 239. 



1867. Sphcera crassicosta, Laube, Bivalven von Balin, t. 3. figs. 5, 6. 



There are three small spherical shells from JSTailsworth in the 

 Jermyn-Street Museum, which perhaps belong to this species. 

 Being closed valves and partly imbedded in matrix, they are difficult 

 to decipher ; but they are smaller and deeper than the specimen 

 figured by Laube. The lunule is smoother, and the escutcheon deeper, 

 though both are undefined. The umbo seems less prominent. The 

 valves are very thick and meet perpendicularly. The shell measures 

 about one line, and possibly may prove to be an Astarte. 



Astaete anatieoemis, n. sp. Plate XYIII. fig. 14. 



Shell large, flattened, attenuated behind. Umbo anterior, acute, 

 proximate and prominent. Lunule sharply excavate, but very flat 

 and shallow. Area small, with a deeply incised line from the exterior 

 ligament. Margin concave in front of the umbo, then becoming very 

 convex on the anterior side, and moderately so on the inferior parts, 

 extremely convex on the posterior side, where the shell is narrowed 

 and depressed, and straight behind the umbo. Hinge large, with 

 one large central tooth and two less distinct lateral ones. Surface 

 covered with numerous faint, irregular, concentric marks, divided 

 into groups by nine or ten deeper lines. 



Length 21 lines, breadth 27, width 8 for the double shell. 



There are two specimens of this species in the Jermyn-Street 

 Museum, from Nailsworth. 



Astaete ceassitesta, P. A. Romer. 



1839. Astarte crassitesta, P. A. Komer, Yerst. ool. Geb. Supt. 1. 19. 

 fig. 18. 



1842. A. crassitesta, F. A. Homer, De Ast. Gen. p. 11. 



1878. A. Mansellii, J. Buckman, Proc. Dorset. Nat. Hist. Club, 

 vol. ii. t. 6. fig. 3. 



The shell described by Mr. Buckman, and which is common at 

 Half-way House, does not seem to be distinguishable from Homer's 

 species. 



