II. STACK A. 26 



fthagrecn, consisting of numerous circular low prominences. Eighteen 

 tutt-, each composed of thirty-five or forty bristles, half a line long, like 

 nt thirk hni.-h, invest the margin of the shell, which consists of 

 -v. n tran-vi-rso plates. The animal is brown ; head and body distinct. 

 It continues soft n-d rock; and gnaws tin- p;i| < ing of ita vessel. 



This last sulistanrr is likewise devoured when purposely introduced along 

 with the animal. The motion of the creature is very slow. It adhere* 

 firmly and tenaciously to subjacent objects. The smoothness of the glaw 

 seems to allure above the surface of the water. But it will generally de- 

 scend when left dry. 



PI.AT: \ 



.13. Chiton fatficularit, upper surface. 

 1 4. The name, under surface. 



2. Cnrrox VULGARIS. Plate V. Figs. 16, 16. 



Length of the shell between seven and eight lines. Figure oval, 

 composed of eight transverse plates, with a flat narrow margin, surround- 

 ed by a very short fringe. Surface like shagreen. Colour grey. The 

 animal is dingy wh: 



It feeds on the common green fucus, copiously on the lamina ria or 

 tangle, an<l it may be occasionally found in considerable abundance on 

 the shore where this substance is common. I have not observed it con- 

 sume any animal matter. 



The motion of this creature is very slow, the flexible nature of the 

 shell and the transverse plates being free to slide on each other, admit 

 "t" various curvature?, adapting the body to the irregular surfaces on 

 which it dwells. 



Spawn, consi.-tini: uf numerous ova amidst albuminous matter, has 

 appeared in the middle of October. 



common Chiton survives readily during a long time. As the. 

 plates of the shell an- nut conm-rU-d by any ligament, they may be sepa- 

 witli facility after it dies, when their peculiar form is discovered to 

 l>e different from what the superficial observer would infer. 



I'LAI : \ 



I"i.. 1"). Chiton ruloarit, upper surt. 

 1 6. The same, under surfaoe. 



