152 RECORDS OF THE AUSTRALIAN MUSEUM, 



and hence generally compressed form ; the longitudinal narrow, 

 and oval section is not seen in any other of our species. 



The costa? are also more truly siginoidal than in other Austra- 

 lian forms. The tubercles are arranged to some extent as in C. 

 plectoides, with intervals occupied by non-tubercUlated costse, 

 and like those of the latter they are always small. On the other 

 hand, there is a most important difference between the initial 

 whorl of the two species, here it forms a free open coil, but in C. 

 plectoides the coil is close and the whorl contiguous ; I regard 

 this initial condition as a very important feature in these shells. 

 The almost flat flanks recall those of C. leptus. 



The general appearance is very Ammonite-like, hence the 

 specific name. 



£ oc . — Barcoo, Ward and Nive Rivers District, South-Central 

 Queensland [A.M. (//. Jf r . Hlomfield)]. Port Douglas [G.S.Q ]. 34a 



CRIOCERAS PLECTOIDES, 35 Sp. 710V. 



(Plate xxxiii., fig. 2; PI. xlvi., fig. 1; PI. xlvii., figs. 1-4.) 



Sp. Chars. — Shell of medium size, robust. Whorls contiguous, 

 at least six, overhanging one another, and rapidly broadening as 

 the shell grew ; initial whorl vermiform, with an acute apex ; 

 venter obtusely rounded, broadening much with age ; abdominal 

 margins rounded, indicated only by the positions of the distant 

 tubercles ; dorsum flat, costate ; impressed zone wide and faintly 

 indicated ; flanks obtusely rounded ; umbilical cavity wide, open 

 and deep, the latter feature arising from the rounded and over- 

 hanging condition of the whorls; section markedly quadrate. 

 Sculpture similar throughout life, consisting of narrow, rounded 

 costse, seldom bifurcate, and varying in strength and distance 

 apart according to position on the whorls ; simply transverse or 

 very faintly concave backwards on the venter, convex forwards 

 on the dorsum, and faintly siginoidal on the flanks. Tubercles 

 obtuse, node like, in one row on each side the median line of the 

 venter, and denning the abdominal margins not otherwise 

 indicated ; at irregular distances apart, but closer in the young 

 condition than during middle life and on single costse ; in the 



34a If Port Douglas, north of Cairns, is meant, possibly a mistake has been 

 committed in this locality. On Dunstan's Geological Sketch Map of Queens- 

 land (1905 the area around Port Douglas is coloured Deseri Sandstone 

 I pper Cretaceous) ; the specimen has all the appearance of a Rolling 

 Downs (Lower Cretaceous) fossil. 

 as n\(KTT) a coil. 



