620 ORDER CHONDROPTERYGII. 



Petromyzon marinus, L. Bloch. 77. The teeth 

 better, Lacep. I. i. 2. (The Great Lamprey.) Two 

 or three feet long, marbled with brown, on a yellow- 

 ish ground. The first dorsal very distinct from the 

 second. Two thick teeth approximating at the top 

 of the maxillary ring. In spring, it ascends into the 

 mouths of rivers. It is an eatable much esteemed. 



Pteromyzon JluviaUs, L. ; Bl. 78. 1. (River Lam- 

 prey.) From one foot to eighteen inches in length, 

 silvery, blackish or approaching an olive colour on the 

 back ; the first dorsal very distinct from the second ; 

 two thick teeth, wide apart, at the top of the maxil- 

 lary ring. It is found in all fresh waters. 



Petr. planeri, Bl. ; Gesner. 705. (Little River Lam- 

 prey.) Eight or ten inches long; the colours and 

 teeth of the preceding ; the two dorsals contiguous or 

 united. It also inhabits our fresh waters '. 



Myxine, L. 



Have but a single tooth at the top of the maxillary 

 ring, which itself is altogether membranous, while 

 the lateral dentations of the tongue are strong, and 

 disposed in two ranges on each side, so that these 



1 N.B. The fig. of the Planeri, Bl. 78. 3. is but a youngjlii- 

 vialis. On the contrary, I think that the Petrom. sucet. Lacep. II. 

 i. 3., Sept-ceil, IV. xv. 1., Noir, lb. 2. are only varieties of the 

 planeri. But the fig. I. ii. 1., under the name of Lamproyon, 

 (Pelrom. branchialis) represents a particular species of this genus, 

 and not an Ammoccetes. I see no certain difference between the 

 Pelrom. argenleus, Bl. 415. 2. and the JluviaUs. 



