132 Mr. L. Reeve on the recent Orbiculse. 



4. Orbicula Cumingii, Broderip, Proc. Zool. Soc. 1833, p. 124. 

 Orbicula Cumingii and strigata, Broderip. 



Hab. Central America, dredged at Payta, St. Elena, Panama, 

 and Isle of Caiia, Guatemala, attached to the lower side of stones 

 in sandy mud at low water, and, in some instances, at depths of 

 from 6 to 18 fathoms : Cuming. Ecuador: D'Orbigny. Ma- 

 zatlan (attached to various shells) : Carpenter, in Cat. Reigen 

 Collection. 



Mr. Broderip's 0. strigata, which he did not describe along 

 with 0. Cumingii in the f Proceedings of the Zoological Society/ 

 but afterwards, when figuring the Orbicula in the ' Transactions/ 

 is a less-worn state of the species, in which there are rays and 

 bands of colour. The upper valve is calcareous and firm, of 

 quite a different type from the horny Orbicula of Chili and Peru. 

 The habitats Malacca and Philippine Islands, given with this 

 species by Mr. Sowerby, are erroneous. He probably mistook 

 specimens of O. stella for it. 



5. Orbicula lavis, Sowerby, Trans. Linn. Soc. 1822, vol. xiii. 

 part 2. p. 468, pi. 26. fig. 1 a, b, c, d. 



Hab. Concepcion, Chili (found attached to Mytili at the depth 

 of 6 fathoms) : Cuming. 



O. IcBvis was first described by Mr. Sowerby in a paper read 

 before the Linnrcan Society in 1820 (but not published till 1822) 

 from a specimen attached to a grey flint pebble nearly coated by 

 the root of an his, of which the habitat was not known. Twelve 

 years later, the species was found attached to Mytili dredged by 

 Mr. Cuming at Concepcion, Chili. It is a stout horny shell, 

 with the surface smooth and faintly malleated. The vertex, 

 which inclines much posteriorly, is conically raised, swollen, and 

 rather obtuse. 



6. Orbicula tenuis, Sowerby, Thes. Conch, vol. i. p. 366, pi. 73. 

 fig. 4. 



Hab. Chili : Cuming. South Australia. 



Compared with the preceding species, 0. tenuis is thinner, 

 rounder, and more depressed. The original group of specimens 

 was collected by Mr. Cuming on the coast of Chili ; but he 

 possesses specimens of an Orbicula of a lighter and more glossy 

 substance, which is perfectly identical with this, from South 

 Australia. 



7. Orbicula lamellosa, Broderip, Proc. Zool. Soc. 1833, p. 124. 

 Hab. Iquiqui and Bay of Ancon, Peru: Cuming. 



This very characteristic species, as related by Mr. Broderip, 



