40 CALIFORNIA SEA- SHELLS. 



1 les A. pelta, with a wider border round the 

 margin. This shell seldom grows more than 

 an inch in length, and is often smaller. 



Acmcea spectrum, Nutt., Fig. 7, PI. X, is a 

 small species, frequently found growing on the 

 shells of other species. It is flattened, with very 

 strong, irregular ribs, which project so as to give 

 it a serrate edge. It is of a gray color outside, 

 and the inner surface is irregularly marked with 

 black and white. 



Loithi gigantea, Gray., Fig. 1, PI. IX, is a 

 fine species, dirty brown or spotted outside, but 

 within it is of a very dark and glossy brown, 

 with a distinct, long, horse-shoe shaped muscular 

 impression. The shell is long, and flattened, 

 with the apex near one end. Length, one to 

 three inches. 



The Chitons are very strange animals, some- 

 what resembling limpets in shape, and like them 

 clinging to the rocks by a broad, flat foot. 

 Their shells, however, are not single, but com- 

 posed of eight plates, which overlap like the 

 scales on a coat of mail. These plates are sur- 

 rounded and partly covered by a muscular man- 

 tle, which is often fringed and ornamented. In 

 their early life the young chitons- have little re- 

 semblance to the more adult forms, for then they 

 consist of only two parts, head and body. Grad- 

 ually the body becomes covered with seven 

 plates, and the head takes shape and developes 

 the eighth. Chitons are a very inoffensive class 

 of animals, and like to live in retired places, 

 especially under stones. Our species are quite 

 numerous, but we will mention enly those which 



