70 



of spines generally large ; gili extending about two-thirds the length 

 of the sides. 



M. De Blainville says, the valves of this genus are always without 

 any trace of lateral area (D. S. N. xxxvi. 537), but this mušt have 

 arisen from his only having exainined worn specimens. 



A. fascicularis. Ch. fasc, Linn. C. echinites, Blainv., Sow. Conch. 

 III. f. 87—93. 



A. Garuoti. Ch. Gamoti, Blainv. D. S. N. 552 ? ; Quoy, Voi/. 

 Astrol. t. 73. f. 9, 14. Ase. Zelandica, Quoy, Voy.Astrol. t. 73. f. o. 

 A. Hookeri, Gray, Dieffenhach, 262. 



A. polychetus. Ch. polychetus, Blainv. 553. 



A. roseus. Ch. roseus, Blainv. 553. 



A. Lesueurii, Ch. Lesueurii, Blainv. 553. 



A. scaber. Ch. scaber, Blainv. 553. 



A. violaceus. Ch. violaceus, Quoy, Voy.Astrol. 73. f. 13, 16, 17, 20; 

 not Sow. III. f. 133. 



A. hastatus. Ch. hastatus, Sow. C. III. f. 127. 



A. hirundiniformis. Ch. hirundiniformis, Sow. C. III. f. 148. 



A. strigatus. Chitonellus latus, Guild. Z. Journ. v. 28. Chitonellus 

 strigatus, Sow. C. III. 



15. Chitonellus, Lam. 



Chitonella, Z)es A. CryptoconchViS, " Blainv.," Burrorvs. Crypto- 

 plax, Blainv. Chitoniscus, Herrm. 



Body elongate, compressed, convex above ; mantle covered with 

 crowded spines ; the exposed part of the front valves oblong, sąuare, 

 broad, often wom ; of the hinder ones narrow, lanceolate ; the platės 

 of insertion large, produced in front, and scarcely notehed on either 

 side. The gills occupy the hinder third of the sides. 



M. De Blainville inserts Lamarck's species of Chitonelli with the 

 spiny Chitons in section D., and in section E. he redeseribes them, 

 from specimens in spirits in the British Museum. 



Chitonellus Isevis, Lam. Chiton vermiformis, Blainv. D. S. N. 

 xxxvi. 553. Oscab. fascie, Quoy, Voy. Astrol. t. 73. f. 21, 29. 

 Cryptoconchus larvseformis, " Blainv." Burroivs, Elem. Conch. 190. 

 t. 28. f. 2, 4 ; Wood, Cat. t. 1. f. 40. Philippines. 



Chitonellus striatus, Lam. ; Sovo. Conch. Illust. f. 62 } Oscab. 

 ocule, Quoy, Voy. Astrol. t. 73. f. 37, 38. Australia. 



The fossil Chitons of the older strata described by Munster, more 

 lately by Ryckholt, Bull. Acad. Brux. 1845, xii. 36. t. 1 — 4, appear 

 to belong to a peculiar genus, which may be called Gryphochiton, 

 most nearly allied to Chitonellus. 



I have described some peculiarities in the development, disposition 

 and structure of the valves of the Chitons in a paper which vili be 

 read at the Royal Society on the 16th of June next. 



