6 RECORDS OF THE AUSTRALIAN MUSEUM. 



are long and stout. Within this family we meet with two genera, 

 Portheus, Cope,^ and Ichthyodectes, Cope/ the latter of which 

 appears to possess stronger affinities with our fossil. In the first 

 of these, the maxillary and dentary teeth are large but of variable 

 size, but in the latter the teeth are of uniform proportion. Fur- 

 thermore, in our fossil the vertebral centra bear lateral longitu- 

 dinal pits, and not mei'e ridges, as in E/o2x>2)sis.^ 



In its present depressed condition, the skull measures seven 

 and a half inches, whilst the transverse width across the combined 

 maxilla? and dentaries is three inches. 



The maxillfe (m.) are stout bones approximately four and a half 

 inches long, but are not perfect anteriorly. The pi-emaxilla has 

 disappeared, leaving a large, open space between the anterior ends 

 of the maxilla;. The dentaries (de.), in consequence of compression, 

 are overlapped by the maxillae, and are stout and strong, approxi- 

 mately five inches long, by five-eighths of an inch deep, with 

 deeply V-shaped posterior ends for the insertion of the articulars 

 (ar.) ; the latter are stout bones also, in keeping with the den- 

 taries, and are about two and a quarter inches long. The superior 

 bones of the skull, in common with the orbits, are so crushed 

 togethei- that an attempt to distinguish them can result only in 

 provisional determination, but perhaps, on the right side parts of 

 the ethmoid and frontal (pth. &/.) ai'e I'epresented by the crushed 

 mass of osseous matter seen above the maxilla. Immediately 

 behind the gape is a curved transverse bone that may be a portion 

 of the hyomandibular or preoperculum {hvi. ■pr-)i and behind that 

 again, particularly on the right side, a flat exfoliated bone, which 

 cannot be other than the operculum {op). From this 

 obliquely inwards to the middle line of the head, is a thick pro- 

 minent surface (])■(/ ■), but thinly-covered with bone here and there, 

 and again repeated on the left side. The two halves form be- 

 tween them a wide open V-shaped figure, casting a deep shadow 

 over the depression in which the vertebra? lie ; possibly this re- 

 presents some portion of the pectoral gii-dle. 



Between the dentaries (de.) at their posterior ends may be seen 

 the diverging hyoids {hi/.), and a number of the branchiostegal 

 rays {br.), the anterior vertebne {v.), some ribs (v.), and the sup- 



8 Cope— Eept. U.S. Geol. Survey Territories (Hayden's), ii., 1875. p. 190. 

 ^ Cope — Loc. cif., p. 205. By Woodward both these <j;enera are placed 



in the Chirocentridse (Brit. Mus. Cat. Foss. Fishes, pt. 4, 1901, 



p. 87), and by Dr. G. A. Boulenger in the Saurodontidse (Cambridire 



Nat. Hist., vii.. Fishes, 1904, p. 561). 

 s Smitl) Woodward— Brit. Mus. Cat. F<iss. Fishes, pt. 4, 1901, pp. 9 



and 99. 



