ERYCINID^. 



221 



BORNiA, Philippi, 1836. Shell elongately oval, with slightly 

 projecting beaks, almost equilateral, surface finely concentrically 

 striated ; hinge with three teeth in the left valve, two small ante- 

 rior and one somewhat remote and elongated posterior, right 

 valve with onl^^ two diverging elongated cardinal teeth ; carti- 

 lage situated in a groove in front of the posterior teeth ; muscular 

 impressions faintly marked. K. corbidoides, Phil., occurs recent 

 in the Mediterranean and the Atlantic, and fossil in miocene beds 

 of Italy and the Vienna Basin. K. seminula, Phil, (cxx, 93-95). 



CYCLADELLA, Carp., 1865. Shell resembling CEdalina in form, 

 thin, umbones flattened ; ligament external, very thin ; the car- 

 dinal teeth lie in the curve of the hinge-line, together with the 

 laterals, which are distant. 



PYTHiNA, Hinds. (Myllita, d'Orb. and Reel.) Shell trigonal, 

 divaricateljr sculptured ; ligament internal ; right valve with two 

 lateral teeth, left with one cardinal and two laterals. 13 sp. New 

 Ireland, Australia, Philippines. Fossil, 2 sp. Eocene ; France, 

 Java. F. Deshayesiana, Hinds (cxx, 96). 



Cyamium, Philippi, 1845. 



Distr. — 3 sp. Patagonia, Northern Europe, U. S. Fossil, 1 sp. 

 Tertiary; Europe. C. Antarcticiim, Phil, (cxx, 97). 



Shell oblong ; hinge-teeth, 2*2 ; ligament double ; cartilage in 

 a triangular groove behind the teeth in each valve. 



TURTONiA, Hanley. Shell oblong, inequilateral, anterior side 

 very short ; ligament concealed between the valves ; hinge-teeth 

 2-2. Animal with the mantle open in front ; foot large, heeled ; 

 siphon single, slender, elongated, protruded from the long end of 

 the shell. Greenland, Norway, Britain ; in pools and crevices of 

 rocks between tide-marks, and in the roots of sea-weeds and cor- 

 allines, Mr. Thompson obtained them from the stomachs of 

 mullets taken on the northeast coast of Ireland. T. minuta^ 

 Hanley (cxx, 98, 99). 



HiNDSiELLA, Stol., 1810. (Hindsia, Desh., 1860. Vasconia, 

 Fischer.) Shell elongately subtriangular, nearly equivalve, with 

 the lower margin insinuated, hinge with one or two (generally 

 one in the right, two in the left) minute cardinal teeth in each 

 valve; ligament external, supported by thin fulcra; muscular 

 impression narrow, elongated, pallial line rather broad, simple. 

 C. lobata, Desh. (cxx, 100). Grignon. 



Thecodonta, a. Ad., 1864. 



Distr. — Th. Sieboldi^ A. Ad. China Seas. 



Shell oblong, very inequilateral, the anterior part being 

 shorter than the posterior, concentrically sulcated ; hinge in the 

 left valve with two diverging cardinal teeth with a cup-like pro- 

 jecting fold between them, a single posterior lateral tooth present ; 



