1$8 Mr. Frembly on some species ofChitones 



centric ridges ; the next rather acutely keeled ; the five following 

 alike : carina broad and smooth, on each side of which is a similar 

 ridge diverging from the beaks, and forming with the carina a 

 sagittate figure, and connected with it by several strongly marked 

 ridges : from under the beaks to the anterior angles of the valves, 

 extend sharp moniliform ridges, each side of which is coarsely 

 striated longitudinally. Border thick, moderately broad, and 

 covered with coarse seed-like scales, which are attached laterally. 

 Length three inches, breadth one and a half. 



The only part of the coast on which we have found this new spe- 

 cies, tvas the south side of Coquimbo Bay : hence its specific 

 designation. The beaks of the large specimens are generally very 

 much eroded, and covered with Patellas, Balani and corallines, 

 but the young shells are often quite perfect ; from one of these I 

 have drawn the above description. I am aware there may be 

 objections to giving the characters of young shells for the identi- 

 fication of species, but in this case an old shell so rarely occurs 

 in even a moderately perfect state, that its characters could scarce 

 have been detailed from such a specimen. 



The habits of this species are very similar to those of C. spini- 

 feruSj with the exception that they seem to be more grega- 

 rious. 



*** LIGAMENTO MARGINIS GRANULOSO. 



3. Chiton Cumingsii. 



C. tesla ovata, valva antica bifariam radiatim granoso-striata ; 

 areis centralibus valvarum longitudinaliter sulcatis, lateralibus 

 radiatim granoso-striatis. 



Tab. Supp. XVI. f. 3. 

 Shell semipellucid, ovate, dirty greenish brown, dorsal mark- 

 ings reddish brown, with spots of black, and laterally with narrow 

 greenish white undulated lines : inside glaucous. Valves eight, 

 the anterior with bifariously diverging granulate striae ; posterior 

 margin a little angular : dorsal valves alike, subcarinated, divided 

 on each side into two parts, the front with fine regular longitudinal 

 striae, the other compartment raised and striated like the anterior 

 valve, as also is the posterior valve behind the beak. Beaks 



