OF MOLLTJSCA. 



22. Ch. Inca, t. 208. f. 2. 



23. Ch. pellis serpentis, t. 189. f. 6, t. 208. f. 6. 



24. Ch. 1, t. 209. f. 1. 



25. Ch. ?, t. 209. f. 3. 



26. Ch. Tehuelcha, t. 207. f. 3. 



27. Ch. Isabella, t. 207. f. 1. 



28. Ch.? Islandica, t. 154. f. 5. 



ff Scales of the mantle small. 



29. Ch. Bowenii, Sow. III. f. 37. Magellan Straits. 



2. Enoplochiton. 

 Mantle covered with oblong, unequal, elongated scales ; valves 

 broad, exposed, thick ; lateral area di- 

 stinct ; plate of insertion of anterior valve 

 lobed, of middle valve with a central nick, 

 of the hinder valve entire, rounded ; the 

 hinder valve with a produced terminal 

 apex. The valves become much eroded 

 (fig. 97). 



1. E. niger. Coquimbo. 



Kg. 97. — Valves of Enoplo- 

 chiton niger. 





JN 



3. Radsia. 



Margin covered with regularly disposed 

 imbricated smooth scales ; margins of in- 

 sertion of the central valves pectinately 

 divided, and each furnished with two 

 notches, of anterior and hinder valve broad, 

 lobed and pectinated ; posterior valve en- 

 tire ; apex superior, subcentral. 



1. R. Barnesii. Coquimbo. 



/ 



m 



1 . 



p 



f 



4. Callochiton. 



Margin covered with imbricate scales ; 

 the valves keeled, the plates of insertion 

 rather short, thick ; of the terminal valves 

 divided into many, and of the central valves 

 into four bifid lobes ; the hinder valve 

 entire. Gills on hinder half of the foot. 



■f Margin with lanceolate, elongate, erect, 

 closely pressed scales. 



1. C. lsevis, Zool. Journ. v. t. 5. f. 1. 



f f Margin with ovate, imbricate scales. 



2. C. evanidus, Sow. III. f. 139. 



A, anterior valve; D, inner 

 surface. B, middle valve ; 

 E, inner surface. C, termi- 

 nal valve, g, antero-cen- 

 tral area. . h & i, notches 

 in margin of insertion. I & 

 m, confines of central area. 



3. C. fuliginatus, A. Adams, Gen. Moll. t. 53. f. 2. 



