LOWER CRETACEOUS FOSSILS — ETHERIDGE. 151 



the most important features is the retention of the tubercles 

 throughout life, or at any rate so far as the latter is known, anil 

 their occurrence on each costa after the cessation of the fasciculate 

 grouping of the costa?. At what precise stage this took place it 

 is difficult to say, as the inner whorls ai'e incomplete. In the 

 figured example, however, the shell had attained to a diameter 

 of four inches before the change from fasciculation to simplicity 

 took place. This change in the sculpture is a very important 

 feature, because in a species to follow C '. flindersi the grouping 

 of the costse continued on to the shaft and crozier, i.e., throughout 

 life. The fasciculi usually consist of three costse, but sometimes 

 two, gathered into a bundle by the conate tubercles, then cross- 

 ing the venter separately ; these fasciculi are separated by 

 from one to two simple ribs. In this grouping of the costse there 

 is a good deal of character, difficult to express in words, for 

 although the early costation of C. nautiloides is fasciculate, the 

 general appearance from that of the present form is quite 

 different. 



Loc— Queensland ! [U.S.]. 



Crioceras ammonoides, sp. nor. 

 (Plate xlix., figs. 1, 2.) 



Sp. Chars. — .Shell small, ammonoid, compressed. Whorls two 

 and a half known ; earliest whorls open and loosely coiled ; later 

 whorls close and contiguous; initial whorl vermiform, with 

 an acute apex (?); venter narrow, depressed convex; abdo- 

 minal margins rather sharp, inclined to be angular ; dorsum 

 and impressed zone unknown ; dorsal or umbilical margin rather 

 sharp and somewhat angular ; flanks broad and almost flat ; 

 umbilical cavity wide and open ; section deltoid-ellipsoidal. 

 Sculpture on the initial whorl of transverse micro-stria?, on the 

 remainder of the whorls either of single or bifurcate costse, or in 

 fasciculi of two ; on the venter straight, on the flanks sigmoidal ; 

 tubercles small and papilla-like, in a single row along each 

 abdominal margin, and at varying distances apart, both on single 

 costfe, or uniting the fasciculi, separated by from one to four 

 non-tuberculated costre. 



Obs.—I have three specimens of this form before me, agreeing 

 in characters and size ; from this I opine they are more or less 

 mature individuals. At any rate they certainly appear distinct 

 from the earlier condition of any of the other species, so far as 1 

 know those portions of the latter. Tl-e species is remarkable for its 

 narrow and almost flat venter, the lateral flatness of the whorls, 



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