88 ' CHITON. 



type is considerable, yet it seems insufficient for specific discrimina- 

 tion, although possibly grounds may be found for separating the San 

 Diego shells as a northern race of the Lower Californian decoratus. 

 The gill-row in this specimen is as long as the foot, as usual in 

 Callistochiton. 



Genus NUTTALLINA Cpr. (Vol. XIV, p. 277). 



N. PiCEOLus Shuttleworth. (Vol. XIV, p. 229). 



This is no doubt a species of the subgenus Middendorffia, not an 

 Acanthopleura. 



Family CHITONID^ Pilsbry. 

 Genus CHITON L. 



Chiton L. ; Man. of Conch, xiv, p. 149. 



Amaurochiton Thiele, Das Gebiss der Schnecken, ii, p. 362 for 

 C olivaceus, cumingi, striatus, tenuistriatus. 



Chondroplax Thiele, t. c, p. 363, for C. granosus and stokesi. 



Diochiton Thiele, t. c, p. 364, for 0. albolineatus. 



Pceciloplax Thiele, t. c, p. 365, for C. glauca Graj,^=quoyi Desh. 



Sypharochiton Thiele, t. c, p. 365, for C. pellisserpentis. 



Georgiis Thiele, t. c, p. 366, for C. rusticus Dh. and " nigrovir- 

 encens" Blv. 



Clathropleura (Tib.) Thiele, t. c, p. 367, for C. siculus Gray and 

 affinis Iss. 



Anthochiton Thiele, t. e., p. 377, for C. tulipa Q. 



The "genera" enumerated above are, in the opiuionof the writer, 

 founded on merely specific characters, or at most they indicate only 

 groups of species of less value systematically than the groups called 

 " sections" in this work. Such multiplication of generic synonyms 

 seems unnecessary and positively harmful. 



C. SQUAMOsus Linne. (Vol. XIV, p. 155.) 



Add to synonymy : Chiton spengleri Blainv., Diet. Sc. Nat. 

 xxxvi, p. 538, and Chiton pictus Blainv., L c, p. 541 (incorrect 

 description of teeth) ; this is C. cymbium of the Museum collection, 

 according to Blainville. 



C. pusio Sowerby. 



This species was described under Jsch)wchiton in Vol. XIV, p. 133, 

 but is is probably a true Chiton, and the same as C. murrayi Had- 

 don, vol. xiv, p. IGl. 



