Of the plates. 475 



Fig. 2. Pleurobranchus luniceps. A new species of the genus 

 Pleurobranchus. a. the penis; 6.6. tentaculaj c. the anus; d.d. 

 the foot which everyv/here projects beyond the body. 



Fig. 3. The animal of an Anomia. a. part of the muscle 

 which is connected with the third valve; b. the foot ; c. a por- 

 tion of the muscle which unites the two large valves; d.d. the 

 mantle; e.e, the shell. 



Fig. 4. The Sigaretus with its fleshy mantle enveloping and 

 concealing its shell. 



Fig. 5. The animal of a Tridacna. a. a fibrous bundle anal- 

 ogous to the threads of the Muscle, by which the Tridacna at- 

 taches itself to rocks; b. aperture for the entrance of water; c. 

 opening corresponding to the anus; d. transverse muscle. 



Fig. 6. A reduced sketch of the beautiful Polydinum diazona, 

 discovered by M. de La Roche, and recognized by M. Savigny 

 as one of the compound Ascidise. 



END OF VOL. II. 



