ACANTIIOPTKRYGIANS. ]43 



AxiNURUS, Cuv. 



^fore elongated tlian the preceding, and without horn or knob, but with 

 tlie same branchial and ventral rays as in the preceding genus ; each side 

 of the tail armed with a single, square, trenchant blade, without a shield; 

 the mouth very small, and the teeth very slender*. 



Priodon, Cuv. 



Combine the notched teeth of Acanthurus, the three soft ventral rays cf 

 Naseus, and the unarmed tail of the Sidjans f . 



FAMILY X. 



The tenth family of Acanthopterygians comprehends a small number of 

 genera, distinguished by 



LABYRINTHIFORM PHARYNGEALS, 



That is to say, that part of their superior pharyngeals is divided into 

 small irregular lamellae, more or less numerous, intercepting small cells, 

 in which they have the power of retaining water for the purpose of being 

 used in moistening the gills when the animal is on shore — an apparatus 

 by which it is enabled to quit the pool or rivulet, which constitutes its 

 usual element, and crawl to a considerable distance from it, a singular 

 property, not unknown to the antients J, and which induces the people of 

 India to believe that they fall from heaven. 



A NAB AS, Cuv. 



It is in this genus that we find the greatest degree of complication in 

 these labyrinths ; the third pliaryngeals, however, have teeth as if paved, 

 and there are others behind the cranium. Their body is round and co- 

 vered with strong scales, their head broad, muzzle short and obtuse, and 

 mouth small; the lateral line is interrupted at its posterior third. The 

 borders of their operculum, suboperculum, and interoperculum strongly 

 dcntated, but not that of the preoperculum. There are five rays in the 



probably the Acanthurus harpuras, Shaw; — Nax. carolinarum, Quoy and Gaym. Zool. 

 du Voyage de Freycin., \A. 63, f. 1; — Nas. tuber, Commers., or Nasor,- Loupe, Lacep. 

 Ill, vii, 3, or Acanthurus nasus, Shaw, Renard, I, f. 79, Valent., No. 119 and 478. 



* Axinurus tUynnoides, Cuv., a new species brought by Quoy and Gaymard from 

 New Guinea. 



f Priudon annularis, Cuv., a new species brought from Timor by the same gen- 

 tlemen. 



X Tiieophrastus, in his treatise upon fishes which live out of water, speaks of small 

 ones which leave their native streams for some time and then return to them, and 

 says that they resemble Mugils. 



