Hyatt.] 320 [April 4, 



type of our genus, Parod. (Gon.) discoideum, sp. Hall, 13, Rep. 

 on State Cabinet and also Nat. Hist. 3ST. Y. Vol. 5, pt. 2, pi. 71, 

 fig. 1-13. 



Tornoceras, 1 nobis, includes species which are similar to Par- 

 odiceras, but have compressed whorls, and annular lobes. The 

 sutures have rounded saddles on the venter and rounded lat- 

 eral lobes with the typical magnosellarian saddles of the family. 

 The first pair of saddles have no corresponding saddles on the 

 dorsum, and the annular lobes are situated immediately between 

 the large dorsal saddles corresponding to the magnosellarian 

 saddles. The ventral lobes and sutures in the larval stages are 

 similar to the adults of Anarcestes. The stage at which the ven- 

 tral saddles are in a primitive condition has close resemblance to 

 the older stages of Parodiceras. Sandberger's figures of Torn. 

 (Gon.) circumnexum, Verst. Nass. pi. 10, fig. 9, and auris, pi. 10 

 a, fig. 19, and Hall's figure of the young of uniangulare show this 

 very well. The effect of the lateral saddles in elevating the in- 

 ternal parts of the septa and the concavity of the outer parts of 

 the same sutures, which remain concave throughout life, are well 

 shown in Sandberger's figures of Torn, auris, pi. 10, a, fig. 4, 5. 

 Torn. (Gon.) discum, sp. Roem. Nordw. Hartz. Paleontogr. Vol. 

 3— pi. 6, fig. 7, and auris, ibid, pi. 6, fig. 11, both have sutures even in 

 late stages, perhaps adults, very similar to those of Anarcestes, 

 according to Roemer's figures. Torn, auris, sp. Sandb. pi. 10 

 a, fig. 12, and Var. pi. 10, fig. 11-12, together with Var. pi. 

 10 a, fig. 18, 19, make together a series which we include 

 under the same name. Var. undulatus, pi. 10, fig. 17-19, also 

 belongs to this species. Torn. (Gon.) retrorsum, sp. Von Buch, 

 has a stout variety similar to auris, the typical variety undulatus 

 Sandb. pi. 10 a, fig. 7, has morecompressed whorls than auris even 

 in larval stages. The young in both of these varieties are smooth, 

 and exhibit no signs of the raised and costated abdomen of auris, 

 though here and there, specimens with reversionary characteristics 

 occur. Var. typus. Sandb. pi. 10, cannot be separated in the larva 

 or adults from the above. Torn, acutum, sp. Sandb. pi. 10, fig. 10, 

 pi. 10 a, fig. 2, can be separated by the sub-acute whorl of the 

 adolescent stage and the breadth of the later lobes and narrow 



1 To'pvos, circular or rounded- 



