CHONDROPTERYGII BRANCHIIS FIXIS. 299 



Gastrobranchus, B1. 



The intervals of the branch!^, instead of having separate issues, 

 communicate with a common canal on each side, each of which ter- 

 minates in a distinct hole situated under the heart, near the first 

 third of the whole length. 



But a single species is known, Myxine glufinosa, L.j Gastro- 

 branchus csecus, Bl., 413; the Glutinous Hag. From the Arctic 

 Ocean. 



Ammoccetes, Dumer. 



All the parts which should constitute the skeleton, so soft and 

 membranous that they are hardly entitled to the appellation of bone. 

 The general form of these fishes, and external orifices of the branchiae 

 are similar to those of the Lampreys, but their fleshy lip is semi- 

 circular, and only covers the top of the mouth, consequently they 

 cannot attach themselves to bodies like a true Lamprey. They have 

 no teeth, but the opening of their mouth is furnished with a row of 

 small branched cirri. They have no particular trachea, and their 

 branchiae are supplied with water from the oesophagus as usual. 

 Their dorsals are united with each other and with the caudal, form- 

 ing a low and sinuous fold. They inhabit the ooze of brooks, and 

 their habits are greatly like those of Worms, which they otherwise 

 so strongly resemble. (1) 



One of them is found in France, the Petrom. branchialis^ L. ; 

 Lamprillion, Civelle, &c. From six to eight inches long, and 

 the size of a large quill; it has been accused of sucking the 

 branchise of fishes, possibly from having confounded it with the 

 Petrom. planeri. It is used as bait. 



(1) See Omaliusde Hallois, Joura. de Phys., May 1808. 



N.li.. The Petrom. rouge, Lacep., II, i, 2, belongs to this genus, and perhaps 

 does not differ materially from the common species quoted. 



