156 EOCENE MOLLUSCA. 



2. AsTARTE DONACiNA, /. Sowerbys MS. Tab. XXIV, fig. 10 a, b. 



AsTARTE DONACINA, Prcstwich. Quart. Journ. Geol. Soc, vol. iii, p. 401, 184/. 

 — — Morris. Catal. Brit. Foss., p. 188, 1854. 



Spec. Char. A. testa transversa, inaquilaterali, crassd, irregulariter quadrangulatd 

 aut donaciformi, partim IcBvigatd, compressiusculd ; pedi-regione brevi, alterd longiore, 

 subtruncatd ; marginibus crenulatis. 



Shell transverse, inequilateral, thick and strong, of an irregularly quadrangular out- 

 line, slightly inclining to wedge-shape ; pedal region short and rounded ; siphonal side 

 truncated ; margins crenulated. 



Length, 1 inch nearly. 



Locality. London Clay; Railway Cutting, Old Basing, near Basingstoke {Prest- 

 wich). 



This is an elegant shell. About half a dozen specimens have been procured by 

 Mr. Prestvv'ich, which he has kindly put into my hands for examination. It is, I think, 

 quite distinct ; and as it has passed under the MS. name of donacina, I have here 

 adopted it. There is a difference in size among the specimens, all of which have a 

 crenulated margin; but whether the smaller ones be young and immature — thus pre- 

 senting an exception to the rule previously laid down — I cannot positively say ; but 

 I think they are all full-grown specimens. Mr. Prestwich said they came from an 

 horizon about fifty feet higher than that at Clarendon. 



3. AsTARTE RUGATA, /. Sowcrby. Tab. XXIV, fig. 13 a—f. 

 AsTARTE RUGATA, /. Sow. Mill. Conch., t. 316. 1821. 



Spec. Char. A. testa crassd, rugatd, rotundato-triangulatd ; pedi-regione rotundatd, 

 siphoni-regione subtruncatd; incsquilaterali ; in juventate rugatd, vel sulcatd ; umbonibus 

 suhprominentibus ; lunuld concavd, profundd ; margine crenulato. 



Shell thick, roundedly triangular ; pedal region rounded ; siphonal side subquadrate 

 or truncated ; inequilateral ; in the young state ridged or sulcated ; umbones rather 

 prominent ; lunule deep and concave ; margins crenulated. 



Diameter, 1 inch. 



Locality. London Clay: Highgate, Hampstead, Potter's Bar, Sheppey {Edwards). 



Mr. Sowerby, in ' Min. Conch.,' has figured several sizes of this shell, which are no 

 oubt from specimens of various ages ; the larger one only has the inner margin, with 



