260 CARDITID^. 



posterior side project or "pout" a little. The foot is 

 slender, remarkably flexible, and extensile. It often 

 assumes a cylindrical shape, especially when the animal 

 is creeping, being dilated with water through an open- 

 ing at the base or heel. It is nearly as long as the shell 

 is broad, and is sometimes thrust out on the anterior 

 side, so as to resemble a tube or siphon, as represented 

 in Forbes and Hanley's plate. The figures given in the 

 present volume were taken from the life by Dr. Saxby, 

 and are perfectly accurate in every particular. 



The European species of Cyamium lives between 

 tide-marks, and literally swarms in some places. It 

 attaches itself to seaweeds and other objects by means 

 of a fine but tenacious byssus. Although it is minute 

 (barely a tenth of an inch from one end to the other) it 

 did not escape the keen eye of the great Otho Fabricius, 

 who described it with his wonted accuracy upwards of 

 eighty years ago. No species has been recognized in a 

 fossil state. The Cyamium ? eximium of Searles Wood 

 appears to belong to another genus. 



Cyamium minu'tum *, Fabricius. 



Venus minuta, Fabr. Faun. Groenl. p. 412. Turtonia minuta, F. & H. 

 ii. p. 81, pi. xviii. f. 7 & 7a, and (animal) pi. O. f. 1. 



Body gelatinous, greyish- white with a faint tinge of purple : 

 tuhe almost sessile : foot very flexible. 



Shell rhomboidal, or inclined to triangular in consequence 

 of the prominence of the beaks, convex, rather thin, semi- 

 transparent and glossy : sculpture, irregular lines of growth, 

 and fine but not close-set intermediate strise : colour purplish- 

 brown, varying in intensity, and sometimes very pale, espe- 

 cially in front : epidermis only observable in bleached speci- 

 mens : margins rounded on the anterior side, with an oblique 

 slope to the front, which has a long and gentle curve, wedge- 



* Minute. 



