148 GENESIS OF THE ARIETID. 
cycloides, Wiih.,' is a slightly more compressed form, which may be transitional 
between the last and the next species, Cal. (Ariet.) Doetzkirchneri. This last is 
figured by Neumayr2 Wiihner’s figures of the young of this species show the 
rounded sides, slight keel, and pile similar to those which proaries has at later 
stages in some specimens, and even in adult stages in others. Cal. (Ariet.) Cas- 
tagnolai, figured by Wiihner,’ shows in its very compressed whorls, narrower 
umbilici, and sharp prominent keel, which are well developed at an early stage, 
when the shell is about 15 mm. in diameter, that the cycle of normal modifications 
is approaching completion. Cal. ( Ariet.) abnormilobatum* gives us the final grada- 
tion. This is a shell having still more compressed whorls, narrower umbilici, due 
to the more involute whorls, and a more attenuated keel. 
This keel and that of Castagnolai leads to the suspicion that it may be hollow, 
but Wihner is too keen an observer, as shown in his complete descriptions, to have 
let such an obvious peculiarity pass unnoticed. His remarks also show that he 
knows how to distinguish between the morphological equivalence of this species 
with Oxynoticeras and its true genetic affinities, as demonstrated by the nea- 
logic stages and their similarities to the later stages and adults of Castagnolai and 
cycloides. Wihner’s descriptions, which we did not consult until we had written 
the above, are sustained by our experience so far as the serial relations and affini- 
ties of Doetzkirchnert, cycloides, Castagnolat, and abnormilobatum are concerned.” 
THIRD SUBSERIES. 
This subseries contains species which have better defined channels and more 
prominent keels in the adults than is common in the second series, and during 
the clinologic stage these are still retained. The whorl in other words becomes 
rounded only in the nostologic stages, and probably very rarely attains this ex- 
treme of modification. The clinologic stage has also slightly flattened and 
inclined sides. 
Caloceras sulcatum, Hyarr. 
Plate I. Fig. 19, 20. Summ. Pl. XI. Fig. 20. 
Amm. Conybeari, Zint., Verst. Wiirt., pp. 3, 35, pl. ii. fig. 4? 
Amm. Nodotianus, Haurr, Ceph. Lias Nordostl. Alpen, pl. vi. fig. 4? 
Amm. kridion, Quenst., Amm. Schwab. Jura, pl. ii. fig. 7 (not fig. 5, 6). 
Locality. — Semur. 
This species is precisely similar to Hauer’s figure, except that the sutures are 
more distinctly caloceran, having the line of auxiliaries inclined backwards. Our 
specimens are also somewhat stouter, the abdomen broader, the channels deeper, 
the geniculze more prominent, but the pile and general aspect of the shell are 
exactly similar. 
1 Mojsis. et Neum., Beitr., V. pl. xxii., xxiii. 
2 Abhandl. geol. Reichsans., VII. pl. v. fig. 1. 
3 Mojsis. et Neum., Beitr., V. pl. xxii., xxiii. 4 Tbid., pl. xxviii. fig. 4-7. 
5 We have given outline figures on Summ. Pl. xi. of Cal. cycloides, fig. 17, Castagnolai, fig. 18, and 
abnormilobatum, fig. 19. ‘ 
