Dr. J. E. Gray on some Families of Bivalve Shells. 21 



II. — Additions and Corrections to the Arrangement of the Families 

 of Bivalve Shells. By J. E. Gray, Ph.D., F.R.S., V.P.Z.S. 



&c. 



One of the advantages, and not the least, of preparing and pub- 

 lishing a revision of the state of our knowledge on any special 

 subject, such as the animals of Bivalve shells, are the additions to 

 that knowledge which its publication induces. During the time 

 my former paper was in the press and since its publication, I 

 have had an opportunity of looking over more than a thousand 

 molluscous animals, and of examining the animals of more than 

 fifty species of Bivalves belonging to nearly as maDy genera, 

 some of them not before observed, which has rendered it neces- 

 sary to make several corrections and important additions to my 

 former communication. 



There must be added to the family Vencrida the genus Cypri- 

 cardia of Lamarck and its subdivisions : all these animals have 

 two short separate siphons and a small pedal opening. I have 

 examined the animal of Trapezium angulatum. 



Mittre has described the animal of what he calls Coralliophaga 

 dactyla, but M. Petit informs us that the shell intended is the Car- 

 dita Lithophagella of Lamarck found in the Mediterranean, and 

 not the Cypricardia Coralliophaga of that author, which is only 

 found in the West Indies. This animal greatly resembles that 

 of Trapezium angulatum, and should be the type of a new genus 

 which may be called Lithophagella. The Cypricardia vellicata 

 and Coralliophaga oblonga have similar animals, but all these 

 genera require revision. 



In the Revision, vol. xiii. p. 410, 1 placed Astartida in the order 

 Veneracea, because Prof. E. Forbes in the ' British Mollusca/ 

 i. 451, described the animal of the genus as having "the mantle 

 freely open with plain margins ; slightly united posteriorly at 

 two points, so as to form two siphoned orifices with simple edges," 

 and at pi. M. fig. 5. figures the animal of Astarte sulcata with 

 two siphonal apertures; at p. 455, he further observes on this 

 species, " the siphonal openings are quite sessile, and but slightly 

 separated from each other;" and at p. 466, he states that the 

 animal of A. compressa has " sessile siphonal orifices." 



I was aware that Philippi (Wiegmann's Archiv, 1839, 125, 

 copied Ann. and Mag. Nat. Hist. vol. iv. p. 297) had described 

 the animal as like Cardita, with only a single anal opening, but 

 placed more faith in the latter description. I have however had 

 an opportunity of examining the animal of Astarte striata from 

 Greenland, which appears to be the same as the A. compressa of 

 the ' British Mollusca,' and find the description of Philippi cor- 



