'^^'^ .HiBllioi^M■^'^ W.iyla?k on t/ie Chitonidw. ,■ 



centre : there are neither eyes nor teutacula : the buccal apparatus 

 consists of two eUiptieal white, or pale yellow corneous plates, 

 between which a rather long, black, strap-shaped tongue passes, 

 armed with a double line of tubercles, the inner edges being 

 tricuspid ; at the base of the corneous plates is a nervous collar 

 of five minute subrotund yellow ganglions ; these are followed by 

 the oesophagus, which leads into a complicated stomach doubled 

 on itself, and is continued as an intestine of four or five folds 

 supported by the liver, which from their complexity can scarcely 

 be described, as they lie in a space of little more than ^th of an 

 inch ; the last fold passes into a moderately long rectum that 

 discharges in the centre of the branchial cordon; the convolutions 

 can be easily drawn out, and with the stomach, oesophageal canal 

 and rectum produce an extent of nearly two inches in moderate- 

 sized examples. The pale yellow, minutely granular, sinuated 

 ovarium is immediately under the mantle, nearly coextensive with 

 the length of the body, and under it are the stomach and other 

 organs, including the large liver of many granular dusky greenish 

 brown lobes. The foot is suboval, very httle angular in front, 

 slightly tapering to an obtuse termination. The under part of 

 the mantle is of a red-brown colour. Between the foot and 

 mantle is the branchial cordon, composed of fifteen oblique cord- 

 like, short, close-set, pale brown fillets, on each side the body, 

 commencing at the right and left of the immediate posterior ex- 

 tremity, leaving between the series only room for the depuratory 

 duct ; the cordon does not quite extend half the length of the 

 body; the fillets gradually diminish in volume from the posterior 

 end, and at the anteal termination are not more than half the 

 length or size of the hindmost ones. There are no traces of male 

 reproductive organs ; and of the other sex, we only meet with the 

 doubtful oviducts, and a conspicuous well-filled ovarium in the 

 genial epoch; it may therefore be inferred that these animals 

 depend on their own individual generative influences, on which 

 we shall perhaps, at a future time, make some observations in a 

 paper on the Patellae ; indeed the present matter would be incom- 

 plete without introducing that group, now omitted, to bring 

 this communication within reasonable limits. 



Chiton asellus, Chemnitz. 

 Chiton cinereus, Auct. " ' 



The anatomy of this species is nearly the same as the precedingy 

 which we have considered the type of the genus, and as the; 

 extemal organs do not vary greatly, I shall only mention the 

 deviations ; the principal, and I believe the only one of the least 

 consequence, is, that there are only ten branchial fillets, on each 



