FOURTH, OR CORONICERAN BRANCH. 189 
Coroniceras Hungaricum, Hyarr. 
Amm. Hungaricus, HavER, Ceph. Lias Nordéstl. Alpen, pl. iv. 
The figure of this species possesses the exact form and characteristic of the 
bisulcatus series. It has similar unshapely genicule thrown out beyond the 
edges of the abdomen, giving the whorl a peculiar angular and squared aspect ; 
the genicule also interrupt the channel ridges, and the keel, though well de- 
veloped, is almost counter-sunken in the deep channels. The pile are very 
straight in Hungaricum, and have no tubercles; the form is also somewhat more 
compressed than in disudcatus. The sides also are perfectly flat and parallel, and 
the depressed abdomen and nearly equally flattened dorsum are of the same 
breadth, the whorl in section being a parallelogram with the sides about one 
fifth longer than the transverse diameter. The specimen figured by Hauer was 
135 mm. in diameter, and consequently the complete shell must have reached a 
much larger size, since his specimens exhibit no signs of the approach of senility. 
THIRD SUBSERIES. 
Coroniceras latum, Hyarr. 
Plate III. Fig. 19-23a. Summ. Pl. XII. Fig. 16. 
Coroniceras latum, Hyatt, Bull. Mus. Comp. Zool., I., No. 5, p. 77. 
Amm. Bucklandi pinguis, Quenst., Amm. Schwab. Jura, pl. ix. fig. 3? 
Locality. —Semur. 
Many of the young of this species, Plate III. Fig. 22, 23, have large tubercles 
early on the second whorl, and on the third these become elongated into tuber- 
cular folds. On the fourth, or on the latter part of the third volution, the inter- 
vals between them increase, and they become true pile. In other specimens, 
Plate III. Fig. 19, the pila are acquired as in rotiforme, Plate III. Fig. 5, and there 
is also in many specimens, Plate HI. Fig. 22, a close resemblance to the adult of 
Cor. kridion, Plate II. Fig. 3. The keel appears on the first quarter of the fourth 
whorl, but at the latest stage observed on the second quarter of the fifth volu- 
tion of a cast the keel was still very thin, sharp, and but slightly elevated. The 
channels, however, though very shallow and broad, had acquired lateral ridges. 
On the second whorl the breadth of the abdomen is very much increased by the 
development of tubercles, the sides becoming exceedingly divergent in some 
specimens, and the abdomen gibbous. On the fourth whorl the central area 
begins to become depressed, Plate ILI. Fig. 23, but the abdomen on either side 
retains its remarkable gibbosity. In correlation with this and with the narrow 
dorsum, the abdomen is never entirely covered by the succeeding whorls, but has 
an exposed border on both sides. On one specimen, Plate III. Fig. 22, 23, both 
the pila and genicule are double; in others, the pilz are single and the genic- 
ulze are double; on another, the duplication of the geniculze ceases on the third 
quarter of the fourth whorl, with the exception of one single genicula on the last 
quarter, which is double. One cast of the second variety was very much broader 
