GASTEROPODA. 161 



1. Tectura virginea. Mull. Tab. XVIII, fig. 6, a — c. 



Patella virginea. Mull. Zool. Dan. p. 13, pi. 12, fig. 4-5, 1773. 



— PARVA. Da Costa. Brit. Conch, t. 8, fig. 11, 1778. 



— - Mont. Test. Brit. p. 480, 1803. 



— EauALis. Sow. Min. Conch, t. 139, var. /3, 1816. 



— — Nyst. Coq. foss. de Belg. p. 349. pi. 35, fig. 5, 1844. 

 var. /3, CONICA. Jeffreys. 



Patella PTJLCHELLA. Forbes ex Loven. 1846. 

 LoTTiA VIRGINEA. S. TTood. Catalogue 1842. 

 AcM/EA VIRGINEA. Thorpe. Brit. Mar. Conch, p. sxxi, 1844. 



T. Testa tenui, dypeiformi, coined, depressd vel elevatd ; suborbicidari vel ovaid ; 

 radils ohsoletis ; vertice obtuso ; margine integro. 



Shell shield-shaped, with an ovate base, elevated or depressed, externally radiated; 

 radii nearly obsolete ; vertex obtuse, eccentric ; margin smooth. 



Longest diameter of base, § of an inch. 



Locality. Red Crag, Sutton, Bawdsey, and Brightwell. Recent, Britain. 



There are two varieties of this species, neither of which is very rare : var. a (fig. a) 

 is ovate, longer than broad, and depressed, with a very eccentric apex ; var. j3 (fig. c), 

 P. conica, Jeff., has a subcircular base, and a more elevated vertex. 



The muscular impression in this shell is precisely similar to that in Patella, and, 

 from the shell alone, could not be distinguished. The apex in all my specimens is 

 more or less eroded. In var. a, the vertex is not more than a quarter of the longest 

 diameter from the anterior margin, with an elevation of scarcely one third ; in var. ^, 

 the vertex is equally eccentric, but the base is less ovate, and its height is equal to 

 two thirds of the longest diameter. 



2. Tectura fulva. Miiller. Tab. XVIII, fig. 7, a — b. 



Patella fulva. Miiller. Zool. Dan. t. 24, fig. 1-3, 1773. 



— FoRBEsii. Smith,. Wern. Mem. vol. viii, p. 59, pi. 2, fig. 3, 1838. 



— acuminata (?). Grateloitp. Bord. Foss. pi. 1, fig. 8-10, 1837. 

 CALYPTR.EA (?) DuBois. Be Montp. pi. 4, fig. 10-11, 1831. 

 Patella fulva. Loven. Ind. Moll. Scand. p. 26, 1846. 



T. Testa minutd, tenui, ovatd, depressd, striatd; striis longitudinalibus regularibus, 

 tuberculatis, vel granulatis ; vertice eccentrico, acutiusculo. 



Shell small, and thin, with an ovate base, depressedly conical, covered with regular 

 tuberculated or granulated rays; vertex eccentric, and rather sharp. 



Longitudinal diameter, ^ ; transverse diameter, ^ ; altitude, ^ of an inch. 



Locality. Cor. Crag, Sutton. Recent, British and North Seas. 



This is by no means a rare shell in the Coralline Crag. The form of the base is 

 ovate, rather narrower on the anterior portion, with a very eccentric vertex ; the 

 shell is generally depressed, although some specimens are somewhat elevated ; and the 



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