Fish-remains from Queensland. 445 



and prefrontal (jof.), an( ^ articulating with each of these 

 bones, is conspicuous on both sides of the fossil. The maxilla 

 (mx.) exhibits the usual broad laminar process (pr.) ex- 

 tending- inwards at its anterior extremity, to be covered by 

 the premaxilla ; and the bone is not much less deep behind 

 than in front. The hinder portion of the upper margin of 

 this element exhibits the slight longitudinal groove noted in 

 other species, and the inferior or dentigerous margin is nearly 

 straight. The maxillary teeth are much broken even on the 

 left side, but all are shown to be stout and hollow, separated 

 by irregular intervals wider than the teeth themselves, while 

 those in the anterior third of the bone are not much longer 

 than those behind. Both premaxillse are displaced and much 

 abraded, but they appear to have been comparatively robust, 

 and the bases of four teeth are indicated in the bone of the 

 right side, these teeth being much larger than any of those of 

 the maxilla. An imperfect section of the premaxilla is given 

 in fig. 1 a, and it will be observed that the teeth are closely 

 pressed together, their extero-internal diameter being the 

 greatest. Of the cheek-plates there are no satisfactory 

 remains, and of the ossified sclerotics only part of that on the 

 right side is preserved. 



Comparison. — The fossil thus described is readily distin- 

 guished from all the known species of Portheus by the cha- 

 racters noted*. To mention only a few points: the Australian 

 species differs from P. molossus and P. thaumas in the greater 

 development of its premaxillary dentition; from P. lestrio, 

 arcuatus, Mantelli, and Daviesi in the straightness of the 

 dentigerous border of the maxilla ; from P. Mudgei and 

 P. gaultinus both in the form of the maxilla and the regu- 

 larity of its dentition. The new fossil may therefore be 

 regarded as representing a hitherto unknown species, appro- 

 priately named P. aiistralis, in allusion to its being the first 

 evidence of the fish from the Southern Hemisphere. 



Formation and Locality. — Rolling Downs Formation 

 (Lower Cretaceous) ; Clutha Station, near Hughenden, 

 Gidgery Creek, Queensland. 



Cladocyclus Siveeti, sp. n. (PI. X. figs. 2-6.) 



Type. — Detached scale ; collection of George Sweet, Esq., 

 F.G.S., The Close, Brunswick, Melbourne. 



* Descriptions of the known species of Portheus are given by E. D. 

 Cope, " Vertebrata of the Cretaceous Formations of the West " (Rep. 

 U.S. Geo]. Surv. Territ. vol. ii. 1875), and by E. T. Newton, « On the 

 Remains of Hypsodon, Portheus, and Ichthyodectes from British Creta- 

 ceous Strata," Quart. Journ. Geoi. Soc. vol. xxxiii. (1877) pp. 509-520. 



