CONCHIFEKA. 295 



the thickened margins (in K. rubrd] ; cardinal teeth 1 or 2, laterals 1 1 in 

 each valve. 



Animal with the mantle prolonged in front into a respiratory canal, either 

 complete (in K. suborbicularis} or opening into the pedal slit (in K. rubra) ; 

 foot strap-shaped, grooved ; gills large, two on each side, united posteriorly, 

 the external pair narrower and prolonged dorsally ; palpi triangular ; pos- 

 terior siphonal orifice single, exhalent. 



The hinges of these little shells are subject to variations, which are not 

 constantly associated with the modifications of the mantle-openings. They 

 creep about freely, and fix themselves by a byssus at pleasure. K. rubra 

 is found in crevices of rocks at high-water mark, and often in situations 

 only reached by the spray, except at spring-tides ; other species range as 

 deep as 200 fms. K. Laperousii (Chironia) Desh. PL XIX. fig. 11, was 

 obtained, burrowing in sandstone, from deep-water, at Monterey, Cali- 

 fornia. 



Distr. 20 sp. Norway New Zealaud California. 



Fossil, 20 sp. Eocene . U. States, Europe. 



Sub-genera. Turtonia (minuta) 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. Distr. 

 Greenland, Norway, Brit. In pools and crevices of rocks between tide-marks, 

 and in the roots of sea -weeds and corallines. Mr. Thompson obtained them 

 from the stomachs of mullets taken on the N.E. coast of Ireland. 



Pythina (Deshayesiana) Hinds. (Myllita, D'Orb. and Reel.) Shell tri- 

 gonal, divaricately sculptured ; ^ligament internal ; right valve with 2 lateral 

 teeth, left with 1 cardinal and 2 laterals. Distr. 2 sp. New Ireland, Australia, 

 Philippines. Fossil, Eocene . France. 



MONTACUTA, Turton. 



Dedicated to Col. George Montagu, the most distinguished of the earlier 

 English malacologists. 



Type, M. substriata. PI. XIX. fig. 13. 



Shell minute, thin, oblong, anterior side longest ; hinge-line notched ; 

 ligament internal, between 2 laminar, diverging teeth (with a minute ossicle. 

 Love'n}. 



Animal with the mantle open in front ; margins simple ; siphonal orifice 

 single ; foot large and broad, grooved. 



The Montacutce moor themselves by a byssus, or walk freely ; M. sub- 

 striata has only been found attached to the spines of the purple heart-urchin 

 (Spatangus purpureus] in 5 90 fms. M. bidentata burrows in the valves 

 of dead oyster-shells. 



Distr. 3 sp. U. S. Norway, Brit JSgean. Fossil, 2 sp. Miocene . Brit. 



