Mr. J. Hogg on some Amphibians. 123 



in Paris. The ovum is like that of all the Batrachians. The 

 gills iu the tadpole of this species consist of three short appen- 

 dages, which are cylindric and only slightly ramified. 



For a full description of the interesting development of the 

 tadpole from the egg of this Amphibian, see the last April 

 Number (16) of the ^Comptes Rendus,' tome Ix. p. 765. 



I may, however, note that it appears that the time required 

 for the hatching of the tadpole of the Axolotl is about one month 

 — the same as that, in our ordinary springs, for the birth of the 

 common tadpole. 



This genus was placed, in my modified Branchial Classifica- 

 tion, in 1841, thus : — 



Class IV. AMPHIBIA. 



Subclass II. Diplopneumena. 



Order III. MANENTIBRANCHIA. 



Tribe I. EAMIBRANCHIA. 



Family II. Proteidae. 



Genus Siredon. 



And I do not think it necessary for me to alter its position, even 

 after a period of twenty-four years. 



But, before I conclude, I must point out two errors in Prof. 

 Agassiz's valuable ' Index Universalis.' 



The first is in attributing to me the word Cadnabranchia, 

 which I have never used. The entry at p. 56 stands thus : — 



"Cadnabranchia, Hogg, Rept. Ad. 1838" (which he corrects 

 to " Caducibranchia)." And he then inserts the following: — 



" Caducibranchia, Bonap. Rept. 1831 " (which he corrects to 

 " V. cadnabranchia"). 



The word Cadnabranchia is, I conclude, only a misprint. 



And the second error occurs at p. 310, as follows : — 

 "Proteidea, Hogg, Rept. Ad. 1841" (which he corrects to 

 " Proteoidce"). 



Now the term " Proteidea," which is seen at p. 355, Ann. & 

 Mag. Nat. Hist.' (No. 45, July 1841), is not my own, but it is 

 that of Prof. J. MiiUer : the original is published in Oken's 

 ^Isis' (p. 710) for the year 1831; and a translation from the 

 German, made by myself, is there inserted. 



Norton House, Stockton-on-Tees. 

 July 11, 1865. 



9* 



