CH7ETOPLEURA. 35 



side of the central areas there are 16 fine rows of beads, not very 

 much developed ; jugular areas not defined ; side areas with irregu- 

 larly scattered grains. Mucro central, depressed. 



Length 28, breadth 17 mill. 



Carpenter seems disposed to unite to columbiensis the species 

 described as scabriculus and luridus, the former of these two being 

 less, the latter more beaded than the typical columbiensis. In case 

 this view is correct, columbiensis will fall into the synonymy of 

 luridus. 



C. ISABELLEI d'Orbigny. PL 13, figs. 57, 58. 



Shell oblong, brown ; back carinated ; front valve and lateral 

 areas of the intermediate valves radiately granulate ; central areas 

 longitudinally granulose-striate. Length 22 mill. (Or&.) 



Bay of San Bias, Patagonia. 



Chiton isabellei ORB., Voy. dans I'Ame'r. Merid. p. 488, t. 65, f. 

 14-19. Tonicia isabellei ROCHEBR., Cap Horn, p. 138. Chceto- 

 pleura isabellei CPR. MS. 



Allied, by its granulated stride, to C. peruvianus, but narrower, 

 more carinated, the girdle smooth. ( Orb.) 



The gills are figured as continuing almost to the front end of the 

 foot. Tn the absence of any information regarding the insertion 

 plates it is impossible to say whether this species is a Tonicia or a 

 Chcetopleura ; if the latter, the girdle is probably not truly smooth. 

 In sculpture it seems near to columbiensis and its allies. 



C. DIEFFENBACHII Reeve. PI. 13, figs. 65, 66. 



Shell somewhat elongately ovate ; valves covered with very min- 

 ute raised dots ; lateral areas scarcely raised ; posterior valve umbo- 

 nated ; variegated with red, green and yellow ; ligament horny, 

 arenaceous. (Rve.~) 



Newcastle) Australia. 



Chiton dieffenbachii RVE., Conch. Icon. t. 22, f. 149 ; species no. 

 148. 



The locality must be regarded with doubt until confirmed. It 

 may prove to be from Peru, and a synonym or variety of C. lurida 

 Sowb. The figure is enlarged. 



C. APICULATA Say. PI. 13, figs. 75-79. 



Shell oval, elevated, light buff or ashen, unicolored or having 

 black patches at the sides or on the ridge (sometimes red or purple 



