CHITON. 395 



leaving only room between the series for the anal aperture. 

 This cordon does not quite extend half the length of the 

 body on each side ; the filaments gradually diminish in 

 size from the posterior end, and at the anteal termination 

 are not more than half the length of the hinder ones. The 

 head is a semicircular puckered frill, within which is the 

 circular rugosely-rayed disk of the mouth, with the round 

 orifice in the centre. There are certainly no tentacula, and 

 no eyes could be detected ; the buccal apparatus consists of 

 two elliptical white or pale yellow corneous plates, between 

 which is a rather long black strap-shaped tongue armed 

 with two lines of tubercles, the inner edges being tricuspid ; 

 at the base of the corneous plates is a nervous cordon of 

 five minute yellow round ganglia ; the tongue is enclosed in 

 a muscular esophagus, which enters a very complicated 

 stomach and intestine of four or five convolutions, com- 

 pacted together by various turns, which, from their com- 

 plexity, can scarcely be described, as they lie in a space of 

 little more than one-eighth of an inch ; at the last turn it 

 passes into a rather long rectum, disemboguing in the 

 centre of the posterior branchial filaments. The convolu- 

 tions can easily be drawn out, and with the esophageal 

 canal and rectum form an extent of nearly two inches. 

 The folds of the liver and ovarium are immediately under 

 the mantle and occupy nearly the whole concave space to 

 the head." — We may add that the axile denticle of the 

 tongue in this species is oblong quadrate, with an entire 

 uncinated apex. The first laterals are very broad and bear 

 strongly hooked dark-coloured apices. 



This species is found under stones at low water, and on 

 stones and shells to a depth of twenty-five fathoms. It is, 

 in the main, an inhabitant of the littoral and laminarian 

 zones, and though seldom occurring in abundance, is so 



