506 



CONCHIFERA. 



escape from the lacerated part. In Pecten the ovary is very conspicuous, 

 from the brilliant colour of the eggs contained in its interior ; it con- 



Fig. 253. 



stitutes the greater part of 

 the hulk of that prominent 

 tongue-like organ which 

 projects between the bran- 

 chiae (fig. 247, /) : or in 

 genera where the foot is 

 very largely developed, as 

 in Cardium rusticum, a 

 great part of the base of 

 that organ is hollowed out 

 into a capacious cavity, 

 enclosed by its muscular 

 walls, wherein the delicate 

 folds of the ovarium (fig. 

 253, a) are partially im- 

 bedded, together with a 

 portion of the intestinal 

 canal (c). 



(1332.) In almost all 

 the Lamellibranchiate A- 

 cephala there is situated 

 on each side of the body, 

 near the insertion of the 

 branchiae, between the ab- 

 domen, the posterior mus- 

 cle of the valves, the heart, 

 and the liver, a gland, of 

 a brown colour, which, 

 from its discoverer, has 

 received the name of the 

 organ or sac of Bojanus*, 

 the nature of which has 

 long been a puzzle to com- 

 parative anatomists. It 

 seems to be intimately in 

 relation with the repro- 

 ductive apparatus, the ex- 

 cretory canals of which 

 always open either into 

 its interior or in its immediate vicinity. This organ is always readily 

 recognizable. On separating the branchial lamellae after placing the 



* " Mem. sur 1'Organe de Bojanus," par Dr. H. Lacaze-Duthiers (Ann. des Sc. 

 Nat. 1855). 



Cardium rusticum. 



