No. 2.] MORPHOLOGY OF THE MYXINOIDEI. 187 



omissions contained in Muller's and all subsequent descrip- 

 tions of the cranial skeleton, we refer to the account which 

 we give in the following pages. 



On page 120 our authors write: "The whole branchial 

 basket lies external to the gill pouches and branchial arteries, 

 not, like typical visceral arches, in the walls of the pharynx." 

 We are now prepared to show that the skeleton of the bran- 

 chial apparatus in myxinoids occupies both positions, and that 

 no such morphological distinction can be made between the in- 

 ternal and external branchial apparatus of the cyclostome fishes. 



On page 128, under head of distinctive characters of the 

 Cyclostomata, Parker and Haswell repeat some of the state- 

 ments already noted and add the following : " The Cyclosto- 

 mata are Craniata in which the mouth lies at the bottom of 

 a sucker-like buccal funnel, and ' has no jaws.' A buccal 

 funnel is present only in the Petromyzontes, for in the Myxi- 

 noids the mouth is terminal. 



" Horny teeth are borne on the interior of the buccal funnel 

 and on the large tongue." This statement is true, as regards 

 the buccal funnel, only of the Petromyzontes, since the funnel 

 is entirely wanting in the myxinoids. The statement that the 

 teeth are also borne on the tongue brings us to a very inter- 

 esting psychological phenomenon. 



Ever since Johannes Muller described the so-called tongue 

 of Bdellostoma, every writer on myxinoid anatomy, as well as 

 every anatomist who has personally studied the anatomy of 

 these forms, has accepted without question or modification this 

 homology, based solely on the authority of the eminent German 

 anatomist. Yet, strange to say, among all other fishes a tongue 

 is held to be absent, and, stranger still, Muller's own account 

 of the organ effectually disproves the homology he sought to 

 establish. For a further consideration of this structure we 

 refer to the body of this paper. 



On page 128 they say that " there is no exoskeleton." This 

 statement must certainly be modified, for the teeth are true 

 exoskeletal structures. 



In Bdellostoma the adult kidney is certainly sometimes 

 both Pronephros and Mesonephros, not simply Mesonephros. 



