Hyatt.] 270 [April 4, 



includes similar forms, but more involute than those of Grypo- 

 ceras, the sutures similar, but with two pairs of lateral lobes. 

 The outer pair arise from division of the ventral lobe by a 

 saddle in the adolescent stages, according to Mojsisovics. The 

 young are apparently identical with Grypoceras, though Mojsis- 

 ovics states positively, that there is no annular lobe. 1 The siphon 

 is above the centre in the type C. Noricus, but below the centre 

 in some species according to Mojsisovics. 



Enclimatoceras, 2 nobis, includes species of the Trias to the 

 Tertiary inclusive, which are connected by the outlines of their 

 sutures. The whorls are involute from an early stage, and com- 

 pressed. The abdomens are rounded, but become acute in many 

 species. The sutures have prominent ventral saddles flattened in 

 species with rounded abdomens, and acute in those with acute 

 abdomens, never divided by ventral lobes ; the lateral lobes are 

 deep, and the lateral saddles well marked. The ventral saddles 

 in the young are broad, and closely resemble the ventrals of the 

 Hercoglossae, as do also the broad, lateral saddles of the later 

 larval stages in some species. There are no annular lobes at any 

 stage in the Triassic according to Mojsisovics. They do not seem 

 to be present in some of the Jurassic and Cretaceous species, at 

 least during the early stages, and are very small in some adults. 

 The Triassic species are nearly related to Grypoceras, according 

 to Mojsisovics figures and descriptions in " Das Gebirge um Hall- 

 statt." The siphon in this type is a little below the centre in the 

 young, though ventral in adults, and this also agrees with the 

 characteristics of Encl. styriacum, sp. Mojsis., of the Trias, and 

 Grypoceras. Nevertheless there is no ventral lobe at any stage, 

 the annular lobe is absent in the Trias forms, and young of later 

 forms ; and the siphon in two species is ellipochoanoidal. Type, 

 Enclim. Ulrichi, White Bull. U. S. Geol. Surv. Vol. not announced, 

 Little Rock, Arkansas, Cretaceous, Nat. Mus. Washington. 



Hercoglossa, Conrad, Proc. Acad. Sci., Philad., 1855, p. 67 

 has for its type Her. orbiculatus, sp. Tuomey, which is described 



1 We think this is probably present, but only to be found in the earlier stages. We 

 desire to call attention to the extraordinary parallelism with the h'gher Goniatites 

 occasioned by the division of the ventral lobe by a secondary saddle, the median 

 saddle. 



2 "E^kXIjic, bent or inclined. 



