468 CYPRINID.E. 



Mactra minutissimu, Mont. Test. Brit. Siippl. p. 37. — Tuht, Conch. Diction. 



p. 83. — DiLLW. Recent Shells, vol. i. p. 143. 

 Goodallia trkingularis, Turt. Dithyra Brit. p. 77, pi. 6, f. 14. — Flem. Brit. 

 Anim. p. 429. — Macgilliv. Moll. Aberd. p. 289. — 

 Brit. IMarine Conch, p. 49. 

 „ minutissima, Turt. Dithyra Brit. p. 77, pi. 6, f. 15. — Flem. Brit. 

 Anim. p. 429. — Macgilliv. Moll. Aberd. p. 290. — 

 Brit. ^Marine Conch, p. 50. 

 Mactrina triangidaris, Brown, 111. Conch. G. B. p. 108, pi. 40, f. 25. 

 „ minutissima. Brown, 111. Conch. G. B. p. 108, pi. 42, f. 25, 26. 



From the imperfect condition of the original specimens 

 of this minute Astarte, arose the error, which, by denying 

 the shell an external ligament, and thus severing it from its 

 kindred species, led to the construction of the ill- based 

 genus Goodallia. As the only permanent difference between 

 the G. triangularis and minima consists of the non-cre- 

 nation of the margin in the latter (which we are not at all 

 sure is ever the case with the adult), we are induced to 

 unite them as one species. 



The contour of this shell is obliquely triangular, and 

 broader than long ; for its size it is remarkably solid, 

 opaque, and perfectly smooth. Both externally and inter- 

 nally it is of a rich yellowish chestnut, either indistinctly 

 rayed with the same hue, but of a darker tint, or uniformly 

 coloured, although when the animal is not removed, there 

 is frequently a slightly mottled or even zoned appearance. 

 Excepting upon the umbones, the valves arc rather com- 

 pressed ; the ventral margin is more or less arcuated, and 

 rises in front, whence originates the peculiar appearance of 

 obliquity in the valves. The anterior side which is de- 

 cidedly the shorter, is rounded at its extremity, the front 

 dorsal edge descending with great abruptness, and but 

 trifling convexity to the ventral, without the interposition 

 of any anterior margin. 



The posterior side is produced below ; its dorsal edge is 



