NATURAL SCIENCES OF PHILADELPHIA. 115 



Ichthyoscopus inermis Swainson, Nat. Hist, of Fishes, Amphibians and Rep- 

 tiles, vol. ii. p. 269. 



Anema inermis Gunther, Catalogue of the Acanthopterygian Fishes, &c, 

 vol. ii. p. 230. 



Habitat. East Indian seas. 



VII. GeNYAGNUS Gill. 



Uranoscopus sp. Cuv. et Vcel. 

 Anema sp. Gunther. 



Head cuboid with its superior surface covered with osseous plates. Pre- 

 operculum unarmed ; both the preoperculum and operculum are covered with 

 the skin. Lower jaw entire beneath. Chin with a barbel ; no intralabial fila- 

 ment. Body covered with extremely minute scales. Dorsal fin long and 

 single, with no spines in front. 



The present genus is distinguished among its allies by the form and arma- 

 ture of the head, the presence of a mental barbel and absence of an intralabial 

 cirrhus, and the condition of the dorsal fin. A single species is known as a 

 native of New Zealand. 



Genyagnus monopteryguts Gill. 

 Uranoscopus monopterygius Bloch, Srhneid., Systema Ichthyologia, Schneid, 



ed., p. 49. 

 Uranoscopus cirrhosus Cuv. et VaL, Hist. Nat. des Poissons, vol. iii. p. 314. 

 Uranoscopus Forsteri, Cuv. et VaL, Hist. Nat. des Poissons, vol. iii. p. 318. 

 Uranoscopus kouripouia Lesson, Voyage de la Coquille, Poissons, pi. xviii. 

 Ichthyoscopus cirrhosus ) Swainson, Natural History of Fishes, Amphibians 

 Ichthyoscopus Forsteri J and Reptiles, vol. ii. p. 269. 

 Uranoscopus maculatus (Sol. MSS.) Richardson, Voyage of the Erebus and 



Terror, p. 54, pi. xxxiii. figs 1 3. 

 Anema monopterygium Gunther, Catalogue of the Acanthopterygian Fishes, 



&c, vol. ii. p. 230. 



VIII. GnATHAGNUS Gill. 



Uranoscopus sp. auct. 



Head with the osseous compartments of its superior surface mostly separated 

 by smooth intervals. Preoperculum not armed with spines beneath ; with 

 about three osseous branches radiating behind and upwards from near its 

 angle. Operculum extended backwards. Lower jaw with a short plectroid, en- 

 largement, directed forwards, preceded in front by an emargination. Intrala- 

 bial filament and mental barbel absent. Body covered with very small scales. 

 Dorsal fin without spines, shorter than usual, and nearly coterminal with the 

 anal, which is of ordinary size. The lateral line is quite distant from the 

 dorsal fin. 



Gnathagnus is one of the most decidedly distinct of any of the genera of 

 Uranoscopinse. It is especially distinguished by its more slender body, the 

 armature of the head, the peculiar short sabre-like dilations of the lower jaw, 

 the great development of the operculum, and the condition of the dorsal fin. 

 Gnathagnus elongatus Gill. 



Uranoscopus elongatus, Temminck et Schlegel, Fauna Japonica, Pisces, p. 28, 

 pi. ix. fig 2. 



Anema elongatum Gunther, Catalogue of the Acanthopterygian Fishes, &c, 

 vol. ii. p. 230. 



Habitat. Japan. 



Leptoscopin.33 Gill. 



Leptoscopinae Gill, Proceedings of the Academy of Natural Sciences of Philada., 

 1859, p. 133. 

 The body is elongated and covered with moderate or rather small scales. 



1861.] 



