MALAC0Z0A. TROPIOPODA. LAMELLIBRAXCHIATA. 339 



end ; the valves very thin, brittle, distinctly or deeply striated 

 concentrically, with stronger growth-lines ; the hinge with two 

 central and two lateral teeth in one valve, two central and on 

 each side a groove with two parallel lamina?, in the other ; 

 the exterior olivaceous brown, or inclining to green, or yellow, 

 in bands, the interior bluish. Length two-twelfths and a-half, 

 height two-twelfths. 



Found by me in the Summer of 1841, in the Inverury 

 Canal. 



Tellina amnica, Muller, Venn. Terr, et Fluv. ii. 205. — Cardium 

 amnicura. Mont. Test. Brit. 14. — Cyclas aninica. Turt. Brit. 

 Biv. 250. PL 11. f. 15.— Cyclas palustris. Drap. Mull. Terr, et 

 Fluv. 131. PI. 10. f. 17, 18.— Cyclas amnicus. Flem. Brit. Anini. 

 453. — Pisidium amnicum. Gray's Turtou, 286, 285. PL 1. f. 5. 



Family VI.— Vexeeixa. P. 210, 254. 



Gexus G. Vexerupis. P. 212, 2C8. 



Venerupis decussdta. Decussated Venerupis. 



Shell ovato-oblong, subrhomboidal, moderately com- 

 pressed, reticulated with divergent and concentric strise, 

 papillate behind, yellowish or reddish, with numerous 

 small, generally angular brown markings. Decussdtus, 

 cut crosswise. 



Shell ovato-oblong, subrhomboidal, narrower or rounded 

 anteriorly, subtruncate behind, considerably compressed, rather 

 thick, reticulated with deep but narrow divergent and concen- 

 tric striae, leaving by their intersection small tubercular pro- 

 minences especially at the posterior end ; the frontal slope 

 short, with an oblong faint, obliquely striate depression ; the 

 three cardinal teeth in each valve close, small, divergent, erect, 

 the middle tooth cleft, the posterior slightly so ; the umbones 

 small, a little curved ; the inner surface glossy ; the siphonal 

 sinus oblong, large, extending obliquely to the middle of the 

 shell ; the exterior reddish-white, with numerous small irre- 

 gular brownish-red markings, darker and more numerous 

 toward the dorsal margin ; the interior yellow, toward the 

 margin white. Length an inch and seven-twelfths, height an 

 inch and a- twelfth. 



The above description is that of an individual found alive, 

 in February, 1843, by Mr. Alexander Beaton, it having been 

 brought up by a fishing-line, from off Aberdeen. It is the 

 only individual that has occurred to me. 



