122 On the Generic Affinities of the New-England Chitons. 



C. Hanleyi. This appeared as Leptochiton Hanleyi in Gray's 

 first paper, but as Acanthopleura Hanleyi in his ' Guide,' 

 p. 183. But in the same book, p. 186, the same species re- 

 appears as Hanleya dehilisj the genus (constituted for that 

 species alone) being said to have lateral tufts of spines ; in- 

 sertion-j)lates entire, of terminal valves alike. H. Adams, 

 following this diagnosis externally, described other species 

 which really had these spine-tufts though not the internal 

 characters. However, on examining every specimen of the 

 species in the market, I could not discern a single spine-tuft, 

 though announced by the accurate Loven. I found, however, 

 excellent internal characters. All the valves were destitute 

 of insertion-plates except the anterior one, which really xoas 

 " entu*e," having one continuous plate, not slit. I did not 

 know whether to believe my own eyes or the testimony of 

 Loven and Gray, till Prof. Verrill allowed me to open the 

 large, smashed specimen of G. mendicariiis. It proved to be 

 a true Hanleia^ according to my diagnosis, but not according 

 to Loven and Gray. I presume that the contraction of the 

 skin in so minute a shell led to the appearance of tufts, and 

 that Dr. Gray supposed that the posterior valve had an entire 

 plate like the anterior. I should be glad of the opinion of the 

 Section whether the genus Hanleia should follow the type 

 against the diagnosis, as here given, or an unreal diagnosis 

 against the type, as followed (in part only) by H. Adams. 

 The animal of this species resembles Lejjtochiton in having 

 short posterior gills, and a central anal tube from which the 

 fgeces were seen to exude. 



7. A similar confusion attends the last and most remarkable 

 species,' 6'. Emersonii. Several live specimens were di-edged by 

 the ' Bluelight,' one of extraordinary size ; and still more have 

 been dredged by Principal Dawson at Murray Bay. For the 

 original species C.vestitus^ from Alaska, a genus ^«i/c?//« was 

 constituted by Gray, characterized by covered valves and re- 

 gular pore-tufts. The elder Sowerby figured the Emersonii as 

 vestitus in his ' Conch. lUustr.' ; hence Dr. Gould naturally 

 looked for the pore-tufts, and found them. Having received 

 a fresh specimen from Dr. Stimpson, I could not find them. 

 I wrote to Dr. Gould, who sent me his type specimens, Vv'itli 

 sketch of regular pore-tufts, as he saw them ; but still I could 

 not. He died without clearing the difficulty ; and I presumed 

 there might be two species, one with and one witliout pores. 

 But after examining both northern and southern suites of spe- 

 cimens, I feel confidence in stating that there are no true pores, 

 but simply a profusion of hair branches, generally very irre- 

 gular, but sometimes, in early stages, more conspicuous at the 



