BY W. HACLEAY, F.L.S. 311 



armature on the side of the tail, which in females is much less 

 developed or entirely absent. Upper jaw with a double series of 

 incisor-like teeth, six in the outer, and four in the inner series ; 

 lower jaw with six similar teeth in a single series. The first 

 dorsal fin reduced to a single strong spine, behind which 

 generally another rudimentary spine. Ventral fins reduced to a 

 simple osseous fixed or moveable small appendage, which is 

 sometimes rudimentary or entirely absent. No barbel. Vertebra? 

 7/11-14. 



Tropical and Sub-tropical Seas. 



1. Anal fin with less thm forty rays. 

 A. Dorsal spine with four series of barbs. 



992. Monacanthus hippocrepis, Quoy & Gaim. 



Gunth., Cat Fishes, VIII., p. 246.— Casteln. Proc. Linn. Soc, 

 N. S. Wales, Vol. III., p. 399. 



Aleuterius variabilis, Richards. Voy. Erebus and Terror, p. 67, 



pi. 53, fig. 1. 



Described in Proc. Linn. Soc, N.S. "Wales, loe. cit. 



Port Jackson, South Australia. 



993. Monacanthus Gunnii, Gunth. 



Gunth., Cat. Pishes VIIL, p. 247. 



D. 34. A. 33. 



Skin velvety, without distinct scales. Body somewhat elevated, 

 its depth being a little more than half the total length without 

 caudal fin. Snout rather produced, with the upper profile very 

 slightly concave. Gill-opening much advanced, its greater 

 portion being in front of the eye ; pectoral fin below the middle 

 of the orbit. Dorsal spine strong, above the middle of the 

 orbit, with a double row of barbs in front and behind, the 



