Fig. 11. 
12. 
13. 
Fig. 1. 
Fig. 1. 
LAMELLIBRANCHIATE CONCHIFERA. 99 
Shows the disposition of the heart, pericardium, excretory organs, &c. in the 
Anodonta anatina. 
Shows the gland of the byssus, mantle, oviduct, &c. of the common salt- 
water Muscle. 
Shows the disposition of the branchie, &c. in the Cardium edule. 
PLATE XIX. 
Animal of the Pecten opercularis, the left valve removed, and the mantle 
turned up. 
. Stomach, intestine, liver, ovary, &c. of the Pecten maximus. 
. One of the ocelli or eyes found on the margin of the mantle of the same, 
and optic nerve, magnified. 
. All the blood-vessels of the Pecten maximus, excepting a set of large veins, 
situated upon the muscle, into which the veins, which are truncated in the 
figure, enter, and which forms the branchial arteries. 
. Nervous system of the Venerupis pullastra. 
PLATE XX. 
Ova of the Unio pictorum from the ovaries and branchie (1; inch focus). 
. Valve of a young Unio, showing that its nucleus is of the same shape as the 
valves of the animals found in the branchie. 
. Fry of the Cyclas rivicola, taken from the branchie (;; inch focus). 
. Ova of the Mytilus edulis (; inch focus). 
. Ova of the Pecten opercularis (; inch focus). 
. Ova of the Anomia cepa (=; inch focus). 
. Globules of the blood, from the auricles of the Pecten maximus (; inch 
8 
focus). 
. Nummulella? branchial process? (4 inch focus). 
. Ova and contained young of a species of Distoma (the two magnified figures 
+ inch focus). 
. Nereis phosphorescens—Syllis, Lam. (2 inch focus). 
. The head of the same (1, inch focus). 
. Animal from the ovarium of an Anodonta as seen in the field of the Micro- 
scope (4 inch focus). 
. Diplotis hyalina? Montag. (+> inch focus). 
