624 



PETROMYZ1D.E. 



intestine, that is, at the junction of the middle and posterior 

 thirds of the animal." 



" The anal fin is a fold of integument, which, commencing 

 at the point where the abdominal folds terminate, is continued 

 to the anus, where it is interrupted, but reappearing behind 

 it, and becoming broader, passes on to be continuous with 

 the dorsal fin at the extremity of the tail. The existence of 

 a median fin in front of the anus is, as has been observed by 

 Miiller, very remarkable ; but it is in exact accordance with 

 a fact mentioned to me by Professor Agassiz, that in certain 

 fresh-water fishes, the developement of which he had watch- 

 ed, a fin of this kind, with rays, exists for a short period of 

 their embryonic existence, and then disappears." 



The minute anatomical details of Professor Mliller and 

 Mr. Goodsir are unsuited to popular pages ; the conclusion 

 appears to be that the zoological position of Amphioxus is 

 the lowest place in the Class of Fishes, and the discovery of 

 a second species in the Mediterranean by my friend Mr. 

 Wilde, which possesses a circular mouth, and some observed 

 habits in the original species, both having been found at 

 Algiers, seem to confirm the connexion of these fishes with 

 the Myxine and Lampreys. 



Extract from a Narrative of a Voyage to Madeira, Tencriffe, 

 and along the shores of the Mediterranean, by W. R. 

 Wilde, M.R.I.A. 



" As I obtained several of the Lancelets during our stay at 

 Algiers, I may be permitted to offer some observations on 

 them. There were two descriptions ; the first, and most 

 common, about an inch and a half long, the Amphioxus lan- 

 ceolatus of Yarrell and the Limax of Pallas, who first noticed 

 it. The body is diaphonous, and enclosed in a thin flexible 

 envelope, not circular, but preserving a five, and, in some 



