LUTRARIA. 



Plate I. 



Genus LUTRARIA, Lamarck. 



Testa cBqwivalvis, inaquilateralis, oUongo-ovata, pleriimqwe 

 compressiiisada, lateribus Jdans, sordlde alba, epi- 

 dermide fused vel oUvaceo-fuscd plus minus indiita. 

 Cardo centralis, latus, dentibus duobits plauo-cochle- 

 ariformibvs lamina triyond erectd, dentibus laterali- 

 bus nnllis. Iinpressio miiscularis pallii shut mayno. 

 Shell equivalve, inequilateral, oblong-ovate, generally 

 rather compressed, gaping at the sides, dirty-white, 

 covered more or less with a brown or olive-brown 

 epidermis. Hinge central, broad, with two flat 

 spoon-like teeth, and an erect triangular lamina, no 

 lateral teeth. Muscular impression of the mantle 

 with a large sinus. 

 Of the miscellaneous assemblage of species described by 

 Lamarck under this head, only two remain as true repre- 

 sentatives of the genus, Lutraria oblonga and L. elUptica, 

 both inhabitants of the British Seas. More than a dozen 

 species from foreign sources have since been added of the 

 same exact type, and we have the pleasure of illustrating 

 them as a very natural and well-defined group. The most 

 abnormal forms are those wliich have been separated by 

 Mr. Gray under the generic title of Zenatia, comprising 

 L. aciriaces, Deshayesii, and Cmningiana; and L. Imiceolata, 

 which is the genus Resania of Mr. Gray. Li the last the 

 interior of each valve is characterized by two verj' promi- 

 nent ledges converging from the hinge, on one of which 

 rests the broad spoon-shaped tooth, as represented in 

 Plate V. They are aU of a smooth didl colourless hue, 

 more or less covered with a dirty-brown or olive epider- 

 mis, and present no sculpture beyond stria3 or wrinkles 

 following the lines of growth. The species are limited in 

 number and widely distributed, being from Australia, New 

 Zealand, Moluccas, Philippines, China, and the Cape oi' 

 Good Hope. They are all natives of the Old World. 



Species 1. (Mus. Cuming.) 

 Ltjtearia Deshayesii. Lutr. testa elongato-oblongd, 

 temdculd, subangustd, concentrice de?ise striata, striis 

 mbrugaformibus ; lateribus aqualiter rotundatis, an- 

 tico prcelongo, valde Jtianie ; ferrugineo-carned, epider- 

 mide viridi-olivaced indiitd. 

 Deshayes' Ldtrabia. Shell elongately oblong, thin- 

 nish, rather narrow, concentrically densely striated, 

 stria somewhat wrinkle-like ; sides equally rounded, 

 the anterior very long, much gaping ; rust-flesh- 

 tinged, covered with a greenish-olive epidermis. 

 Lutraria Solenoides, Deshayes (not of Lamarck). 

 Sab. New Zealand ; Earl. 



A thin delicate Solen-\ike shell, with the peculiar shelf- 

 like tooth wliich serves to characterize Mr. Gray's genus 

 Zenatia, conspicuously developed. 



Species 2. (Mus. Cuming.) 



Lutraria elongata. Littr. testa elongatd, ventricositis- 

 culd, latere postico late rotitndato, antico attenuato- 

 rotundato ; concentrice irregulariter striata, striis me- 

 dio snbobsoletis, ad latera rugceformibus ; albidd, epi- 

 dermide lutescente-cinered indutd. 



The elongated Lutraria. Shell elongated, rather 

 ventricose, posterior side broadly rounded, anterior 

 attenuately rounded ; concentrically irregularly stri- 

 ated, striae nearly obsolete in the middle, wrinkle- 

 hke at the sides ; whitish, covered with a yeUowish- 

 ash epidermis. 



Gray, Ann. and Mag. Nat. Hist. 1837. 



Eab. ? 



Chiefly distinguished by the subatteauated form of the 

 anterior side of the shell. 



Species 3. (Mus. Cuming.) 



Lutraria elliptica. Lutr. testa ovato-oblongd, subven- 

 tricosd, irregulariter concentrice striata, striis hie illic 

 riigaformibus ; lateribus subaqualiter rotundatis, an- 

 tico longiore ; incarnato-albd, epidermide virescente- 

 olivaced indutd. 



The elliptic Lutraria. Shell ovately oblong, subven- 

 tricose, irregularly concentrically striated, striae here 

 and there wrinkle-like ; sides nearly equally rounded, 

 anterior the longer ; flesh-tinted white, covered with 

 an olive-green epidermis. 



Lamarck, Anim. sans vert. (Deshayes' edit.) vol. vi. p. 90. 

 Mactra lutraria, Linnseus. 



Hab. Seas of Europe. 



This weU-known European species, compared with the 



rest of the genus, has a peculiar Anodon-like aspect. 



Species 4. (Mus. Cuming.) 



Lutraria Philippinarum. Lutr. testd elongato-oblongd, 

 ventricosd, snbobliqud, concentrice tenuistriatd, striis 

 anticis rugceformibus ; lateribus subattenuato-rotunda- 

 tis, antico paulo rostrato, aperte hiante ; albidd, epi- 

 dermide tenui cinereo-lutescente indutd. 



The Philippine Lutraria. Shell elongately oblong, 

 ventricose, rather oblique, concentrically finely stri- 

 ated, anterior striae wrinkle-like ; sides somewhat at- 

 tenuately rounded, anterior a little beaked, openly 

 gaping ; whitish, covered with a thin ash-yellow epi- 

 dermis. 



Deshayes, Pro. Zool. Soc. 1854. 



Mab. Philippine Islands ; Cuming. 



Distinguished by its elongately oblong form and by 

 the more attenuated roundness of the sides, the anterior 

 of which is a little beaked and openly gaping. 



August, 1854. 



