PLATE XII {contuiued). 



63. — ChHon piceus, Antilles. Median small, reflexed, extremity articu- 

 lating with a narrow tooth, the other end of which is connected 

 with a strong tricuspid tooth, and flanked by three teeth, reflexed, 

 symmetrically placed on the basement membrane. 



6i. — Chiton echinafus, Valparaiso. Odontophore long and narrow ; an inch 

 and a half in length by one hfth of an inch wide ; a good deal of 

 colour, orange-red. Median narrow, reflexed ; articulating with an 

 irregular-shaped tooth, and also connected with a strong-hooked 

 tricuspid tooth, and this again is flanked by five small subquadrate 

 teeth, the outer of which is the largest. Basement membrane 

 dense, and the central part appears to be made up of a set of 

 muscular bands, crossing and recrossing each other at right angles. 



65. — Chiton {tmdnlatus ?), Birmah. Mounted dry, and showing many points 

 of interest. The medians — indeed all the teeth — are observed to 

 be erect and hooked, or reflexed. Pleurse armed, first and second 

 have a chisel-shaped cutting edge ; third, a black-coloured dense 

 tooth, is armed with two or three strong cusps, and flanked by 

 three or four slightly reflexed teeth, symmetrically placed on the 

 membrane, a portion of which is shown in the drawing. 



66. — Patella spinosa, Cape. The odontophore in this species appears to 

 take the semicircular form, the median is much subdued in some 

 it is said to be wanting. It is, however, quite rudimentary, and 

 scarcely possible to say what the exact form is. Median rudi- 

 mentary. Pleurse armed, 1st small, narrow, i-eflexed ; 2nd hooked ; 

 3rd dense, tricuspid ; flanked by three subdued or rudimentary 

 teeth, reflexed. 



67. — Fatella pellucida, Brit. Numerous small pellucid teeth, on a narrow 

 band. Median apparently wauiing. Pleurae armed, 1st and 2nd 

 similar, reflexed, or hooked; 3rd broad-headed, with some three 

 or four or hooked denticulate. 



6S.— Fatella guttata, Yigo B&j. Odontophore very long; exceeding four 

 inches in length, with 280 rows of teeth. Median much subdued. 

 Pleurae armed, 1st narrow, reflexed ; 2nd larger, hooked ; 3rd broad, 

 bold, tricuspid, flanked by three translucent, slightly reflexed teeth. 



69. — Fatella crenata, Madeira. Odontophore broader and shorter than 

 former specimen. INIedian much subdued or wanting. Pleurte 

 armed, 1st and 2nd reflexed ; 3rd broad, hooked, tricuspid, flanked 

 by two or three similar teeth. 



70. — Fatella radiata, Brit. Odontophore seen in profile. Teeth long and 

 slender, hooked, placed in a radiating series, all similar in ap- 

 pearance ; three similar on outer portion of band. 



71. — Fatella denticulata. Cape. Median small and narrow, reflexed. 

 Pleurse armed, 1st dense, clump-headed, with two or three strong 

 cusps subdued, hooked; 2nd large, bold, tricuspid; 3rd similar, 

 tricuspid, central cusp much produced ; flanked by three small 

 reflexed teeth. 



72. — Lepeta caca {Fatella or Acmma cceca,)^ Greenland. Median reflexed, 

 hooked, and acutely pointed. Pleurae armed, 1st narrow, reflexed ; 

 2nd reflexed, similar. Odontophore minute and narrow. Teeih 

 set in separated bands of membrane, formula of which api)ears 

 to be 2 — 1 — 2. a Medians ocen in profile. 



