164 NEW-YORK FAUNA MOLLUSCA. 



I refer to this species, a Chiton found in the harbor of New-York, attached to the ovaries 

 of F. canaliculahis, and kindly placed at my disposal by Dr. Budd. It has a conspicuous 

 series of holes on each side, between each valve, near their lateral margins ; the lateral 

 membrane appears to have been bordered with white. In other respects it agrees with the 

 description given above. 



Chiton apiculatus, 



PLATE X. FIG. 201 anj 2C2. 



Chiton apicidatxis. Say, American Conchology, No. 8, fide Gould. 



C. pecttnatus, Gould. C. apiculatus, Id. Invertebrata of Mass. p. 14G, fig. 20. 



Description. Shell oblong-oval, convex; valves obtusely carinate, the central portion of the 

 posterior margins becoming slightly beaked with age. Lateral areas triangular, studded with 

 numerous rounded tubercles, disposed in no regular order, obsolete towards the apices, more 

 numerous towards the lateral margins, which are rounded with an elevated marginal line. 

 Medial areas lozenge-shaped, with numerous elevated rounded dots arranged in ten or twelve 

 series on each side of the carina, parallel with the longitudinal axis of the body. In aged 

 individuals, the lateral margins of the valves have the tubercles arranged in concentric lines ; 

 terminal valves with concentric dotted lines ; margin membranaceous, obscurely granulate. 



Color, variable; when freshly captured, greyish, inclining to ashen : in cabinets, they often 

 appear bluish or ferruginous. 



Length, 0-5 -1-0. Width, 0-3-0-6. 



I had indicated this species as C. jayi, when Dr. Jay obligingly favored me with specimens 

 precisely similar, labelled " pectinatus, Gould." I therefore adopted the name, although I 

 had not met with the description. More recently, the publication of the manuscripts of Mr. 

 Jay has made us acquainted with the fact that he had described this species under the name 

 which it bears at present. 



It is rather a common species, and is frequently found adhering to oysters. Like their 

 congeners, they are parasitic, and, when detached, are capable of moving with considerable 

 rapidity through the water. It has a wide range, having been found from South-Carolina 

 nearly to Cape Cod in Massachusetts. 



(EXTRA-UMITAL.) 



C. marginatus, Pennant. (Gould, Op. cit. 147, fig. 22.) Shell small, ovate, carinate and pointed 

 behind: surface apparently smooth, but, under the lens, minutely shagreened in diamond-shaped 

 granules. Color, dull ashen or greenish. Length, 0-5; width, 0-3. Very rare. Seacoast of 

 Massachusetts. 



