605 



PYLOBIDIA. 



PYLORIDIA. 



606 



The Anatince have hitherto been found for the most part in sands 

 and shallow water. 



Analina sulrostrata, 



a, Inside view of valve, ihowing the hinge, &c. j h, oxteinal view ; valves 

 closed. 



Mt/a. Animal oblong, a little compressed, enveloped in a rather 

 delicate mantle adhering by its borders, closed by a membranous 

 lamina, and forming backwards round the tubes a loose envelope in 

 which they are withdrawn ; tubes united, of moderate length, a little 

 separated at their summit and radiated at their orifices ; foot very 

 small, conical, coming out of the mantle by a small slit situated at its 

 antero-inferior border, in the median line; bnuichue moderate, not 

 much elongated, unequal on the same side; mouth small, having 

 triangular appendages striated like the branchiae. Shell enveloped 

 with an epidermis prolonged upon the tubes and mantle of the 

 animal, rather solid, gaping at both extremities, equivalve ; umbones 

 projecting but little ; hinge composed of one or two oblique folds, 

 diverging backwards from a horizontal, compressed, spoon-shaped 

 process, belonging to the left valve and corresponding to an equally 

 horizontal fosset in the right valve ; ligament internal, inserting itself 

 between the fosset and the spoon-shaped process ; muscular impres- 

 sions distant, the anterior elongated, the posterior rounded; pallial 

 impression narrow and deeply excavated. (Rang.) 



There aro ten species. They are found in the northern seas, west 

 Africa, the Philippines, Australia, and California. 



The Myie live buried in sandy beaches, wherein they often lie with 

 the tube just projecting : they are also found in the silt of actuaries. 



M. arenaria has the shell ovate, rounded anteriorly. The subjoined 

 cut shows the hinge, muscular impressions, markings, and general 

 form of the shell. 



Mya arenarii. 



It is found in the British Channel and European seas. It burrows 

 a foot deep. It is eaten in Zetland and America, and is regarded as 

 excellent food. 



Lutricola. Body oval, very much compressed or eubcylindrical, 

 the mantle only closed in the half of its lower border ; foot small, 

 projecting but little beyond the abdominal mass ; tubes long, distinct 

 or united. Shell oval or elongated, regular, equivalve, more or less 

 inequilateral, sometimes scarcely gaping, the edges constantly simple 

 and trenchant, the umbones but little marked ; hiuge subsimilar, 

 formed of two very small diverging cardinal teeth, sometimes effaced 

 before a large triangular fosset; ligament double, the external posterior 

 rather small, the internal much thicker, and inserted in the fossets ; 

 two distinct muscular impressions united by a pallial impression, which 

 is deeply sinuous backwards. (De Blainville.) 



M. De Blaiuville divides the genus Lutricola into the two following 

 sections : 



A. Oval or orbicular species nearly equilateral, very much com- 

 pressed, gaping but little ; hinge similar ; internal ligament 

 inserted in the fosset of a vertical spoonshaped process ; two 

 distinct tubes. Genus Liyula, Leach. 



* Without longitudinal stria:. 



L. compressa has the shell somewhat thin, compressed, roundeil- 

 trigonal, squalid, transversely striated, dirty gray, sometimes yellowish 

 or reddish. It is found in the British Channel. 



Ltitricola compressa. 



** Stria; from the urnbo to the base. 



L. ruyoia (Maclm rugota, Gm.). It is found in the European seas. 

 B. Oblong species, subcylindrical, gaping very much ; two very 

 strong hinge-teeth ; spoon-shaped process of the ligament verti- 

 cal. Genus Lutraria, Lam. 



L. tulenoides (Mya oblonga, Gm. ; Mactra kians, Dilw.) has the shell 

 oblong, with transverse rugiform striao, anterior end very long, apex 

 rounded, gaping much ; dirty white or reddish. It is found in the 

 European seas. 



Lutraria solcnoides. 

 a, Internal view of valve ; b, external view. 



The genera above collected under the name of Lutricota by M. De 

 Blainville belong to the genus Lutraria of Lamarck. [CoNOHAOEA.] 



There are 18 species of Lulraria found in the United States, Brazil, 

 the Mediterranean, Senegal, Cape of Good Hope, India, New Zealand, 

 Sitka, and the British Islands. 



Section 2. (Ligament external and convex.) 



Ptammocola. Of the genera, or rather sub-genera, enumerated by 

 M. De Blainville, of this genus, M. Deshayes is of opinion tlmt the 

 genus Ptammobia should be retained. It comes near to the Tellina?, 

 differing from them more in the shell, which has not the irregular 

 posterior bend, than in the animal, if reference be made only to the 

 figure of Poll. The species figured by Messrs. Quoy and Gaimard, 

 in the 'Voyage of the Astrolabe,' presents particular characters, 

 observes M. Deshayes, different from those which Tellince have hitherto 

 shown. Peammolcea, he thinks, should not be continued as a geuua. 

 (Edit. Lam.) 



The species are numerous. In his 'Tables,' M. Deshayes gives 

 eighteen as the number of recent Ptimmobia, and notices four as 

 fossil (tertiary). Piammobia vttpcrtina and P. murieata he notes as 



