98 CARDIAD^E. 



siderations appear to support us in having transferred this 

 species from the Kelliadte to a separate family. 



It is well to mention that the figure referred to of this 

 animal is incorrect, from the engraver having placed the foot 

 and siphon at the wrong ends ; the position of each should be 

 reversed. 



A family of only one genus, of nine species. This is a well- 

 marked group by its radiating ribs, which are either nodose, 

 spinous, or vaulted, with interstitial furrows of transverse 

 waved strise. The tubes are short or sessile, but in some 

 species an imperfect pallial siphonal sinus may be seen. The 

 animal is distinguished from every other bivalve tribe by the 

 extraordinary length of the subcylindrical geniculated foot, 

 and by the external surface of the siphons being clothed with 

 long pendulous filaments. 



CARDIUM, Linnseus. 



C. ECHINATUM, Linnaeus. 



C. echinatum, Brit. Moll. ii. p. 7, pi. 33. f. 2. 



Animal suborbicular, pale yellow; mantle open, with the 

 margin slightly dentated, pale brown, forming a branchial 

 and anal siphon, which are | of an inch long, in a shell of 

 about an inch- and- a-half vertical and transverse measure; 

 they are of a dirty white hue, united or soldered on each 

 other, and have not the aspect of a single sheath ; the anal is 

 rather the shortest and smallest, and protrudes a plain globular 

 valve at its termination; each is fringed with about 15-20 

 white cirrhi, having at their bases short, dark yellow, and 

 minute close-set brown lines, which give the orifices of the 

 siphons the appearance of being encircled by a fine line, and 

 on the external surface of each there are long, somewhat 

 curved white filaments, which also for a short distance clothe 

 the mantle above and below them. The foot is subcylindrical, 



