CIRCE. 447 



Cyfrina mhitma,TvRT. Dithj-ra Brit. p. i;57. — Fi,em. Brit. Anim. p. 444. — 

 Brit. Marine Conch, p. 82, f. 102.— Hanl. Recent Shells, 

 vol. i. p. 95. 



Cy}y)-ina triangularis, Turt. Dithyra Brit. p. 136, pi. 11, f. 19, 20. — Flem. 

 Brit. Anim. p. 444. — Brit. Marine Conch, p. 82. — Hanl. 

 Recent Shells, vol. i. p. 95. 



Cytlierea triangularis, Macgilliv. Moll. Aberd. p. 268. 



Cytlwrea apicalis, Philippi, Moll. Sicil. vol. i. p. 40, pi. 4, f. 5. 



Circe triangularis. King, Ann. Nat. Hist. vol. xv. p. 112. 



Cythcrea Cyrilli, Phimppi, Moll. Sicil. vol, ii. p. 32. — Hanl. Recent Shells, 

 suppl. pi. 15, f. 26. 



Cytlierea, minima. Brown, 111. Conch. G. B. p. 92, pi. 37, f. 3. 



Cytlierea minuta, Bro'.VN, 111. Conch. G. B. p. 92, pi. 37, f. 4, 



Montagu having first established his Venus minima from 

 the young of the more rounded variety, subsequently 

 founded his V. triangularis upon the aberrant colourless 

 triangular form which is chiefly obtained in our more 

 northern waters. The subsequent discovery of interme- 

 diate examples has compelled us to unite these two shells. 



The shape is rounded subtrigonal, and the valves are 

 solid, opaque, glossy, typically somewhat compressed, but 

 occasionally even subventricose ; the convexity is about 

 equal on either side. The exterior of the shell, which is 

 not greatly inequilateral, is covered with broad and rather 

 unsymmetrical concentric grooves, which are disposed at 

 moderate distances from each other ; their interstices in 

 certain examples assume the appearance of depressed con- 

 centric costella;. The colouring is infinite in diversity ; 

 sometimes the external surface is pure and unmixed white, 

 more frequently, however, the exterior is variegated with 

 larger or smaller pyramidal spots of a livid red, arranged 

 in one or two subcentral rays (which rarely commence at 

 the umbones) ; sometimes, too, these spots are squarish or 

 amorphous and very distant. One variety is of an uniform 

 pale livid lilac, another is entirely of a rich roseate flesh- 

 colour, another subradiatingly mottled witli livid or brown- 



