120 CRETACEOUS PELECYPODA 



as yet been observed : I do not think that the anterior internal rib is of any generic 

 importance, for such ribs are not unusual in various species of Tellitice. In 

 general form M. Couloni resembles our Pulceomcera inconspictta, but this has 

 all the characters of the latter sub-genus, the hinge-teeth being distinct ; still it is 

 the only shell I know which can be compared with the European type species. 

 Possibly Mactromi/a may stand near Metis, for in some species of this sub-genus 

 the few cardinal teeth become almost quite obsolete, but then it is again to be 

 observed that all species of Metis are thin shells. 



10. Strigilliiia, Turton, 18-22. Shell svib-orbicular, posteriorly slightly pro- 

 duced and narrower ; surface glassy and divaricately striated ; hinge with the 

 cardinal and lateral teeth well developed ; sometimes there is in each valve only 

 one strong, sometimes two cardinal teeth. Strig. carnaria is the type of this 

 genus. The shells are very characteristic, and though resembling in shape and 

 dentition Tellinte, the glassy divaricately striated surface is so peculiar that a 

 generic separation seems advisable. They are externally very much like lacree 

 and other divaricately striated species of the Scbobiculabiidm, and must be con- 

 sidered as truly representative types. 



c. Siib-familif—CAFSIN^. 



The shells included in this sub-family are characterized by an inflated form of 

 the valves, these being generally radiately striated ; the hinge only possesses 

 cardinal teeth, but the animals do not differ from typical tellinin^. 



11. Macalia, H. Adams, 1860, (Proc. Zool. Soc, Lond., p. 369). This genus 

 has been proposed for the type Tell. Brugnieri, Hanley. The shell is sub-orbicular, 

 rather solid and inflated, posteriorly with a moderate ridge, nearly equivalve, the 

 beaks are prominent, the ligament situated in a deep groove ; the hinge with 

 two very strong cardinal teeth in each valve. 



12. Gastrana, Schuhm., 1817. Shell transversally elongated, often sub- 

 trigonal, inequilateral, more or less inflated ; hinge with two diverging cardinal 

 teeth in each valve, the anterior in the left usually bifid and stronger than any of 

 the others ; no lateral teeth are present. The best known species, Gast. fragilis 

 of Linne, may be considered as the type of the genus. Eossil species are known as 

 yet only from tertiary deposits, but it is possible that some of the species 

 described from older formations as Capsa belong to Gastrana. The recent species 

 burrow in sand and mud ; I met with one species near Akyab (Arracan coast) 

 burrowing in a soft sandstone bank in company with a Petricola. 



13. Cajysa, Bruguier, 1791, (Asaphis, Modeer, 1793). Shell oblong, 

 ventricose, eqviivalve, posteriorly widely gaping ; surface of valve radiately striated ; 

 hinge with two diverging cardinal teeth in each valve, pallial sinus spacious. 

 Linn^'s Venus dejlorata (Sangtiinolaria rugosa of Lamarck) must be con- 

 sidered as the type of this genus. Reeve describes only two species, H. and A. 

 Adams quote four, but they may all be considered as varieties of the same species. 

 A large number of fossil species had been described under the generic name Cnpsa, 



