144 DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 



HOPLEGNATHUS. 



The Museum of Haslar Hospital contains a specimen of a Scaroid fish which was 

 obtained by the late D. B. Conway, Esq., Surgeon of the Royal Navy, in a voyage to 

 Australia. As Mr. Conway was Medical Superintendent of a convict ship, which is 

 not allowed to touch at any port in the voyage out, and the fish belongs to a littoral 

 tribe, it is probable that the specimen was procured either at Sydney or Hobart Town, 

 but there is nothing except this presumption to guide us to its real habitat. This fish, 

 with jaws similar in construction to those of the true Scari, has a continuous lateral 

 line like Odax, but it differs from both these genera in the smallness of its scales, and 

 from the Lahroidea in general in its scaly vertical fins. I have therefore invented for it 

 the new generic name of Hoplegnathus^ (from on-Xrj ungula, and yi-afloc, denies, maxilla), 

 in allusion to the horse-hoof form of the jaws, with which the teeth are incorporated. 

 The specimen being merely a mounted one, I am unable to complete the generic cha- 

 racter by describing the form of the pharyngeal teeth, and giving other details of the 

 internal structure, but the external aspect is so much that of a scienoid fish, and so 

 unlike to any of the Labroidecs, and particularly to the subdivision of the family with 

 which it is most naturally connected by its dentition, that there seems to be a propriety 

 in giving it a proper generic name, if for no other purpose than that of directing the 

 attention of ichthyologists to this curious annectent form. 



In dentition and construction of the jaws Hoplegnathus approaches more nearly to 

 the typical Scari than to Odax, but the upper lip covers two-thirds of the intermaxilla- 

 ries, and moves with these bones, provision being made for this motion by a deep, 

 smooth, transverse furrow which separates the lip from the integuments of the nose. 

 The bony operculum has two rounded lobes with a deep semicircular notch between 

 them, and its surface, as well as that of the large cheek, is protected by small scales. 

 The scales of the body are also small, not very regularly disposed, and encroach on the 

 base of the soft parts of the vertical fins, fillets of much more minute scales running 

 up between the rays to two-thirds of their height. On the caudal these scaly stripes 

 run nearly to the ends of the rays. The spinous rays are strong, round and sharp, 

 very unlike the flexible spines of Odax, and stronger than in any Scartis which 1 have 

 seen. The anal contains three spines. The lateral line is composed of a series of 

 simple tubular elevations, disposed in a regular curve parallel to that of the back, until 

 it reaches the end of the dorsal, when it takes a straight course through the tail. In the 

 specimen it is continued for some way over the caudal. In Odax the lateral line changes 

 its direction much further forwards, while in Scarus it is interrupted. 



Hoplegnathus, genus novum. 



Corpus ellipticum, crassum, squamis parvis oblongis tectum. Linea lateralis continua. 

 MandibultB modo Scarorum dentes incorporates gerentes. Labium superius basi 

 ' 'This word was misspelt Oplegnathus in the Proceedings. 



