1533.] 333 [Hyatt. 



[Belocerae.] 

 Sandbergeoceras, 1 includes species with peculiar saddles and 

 obes, which are variable in number and larval in their outlines. 

 The shells are discoidal, the form of the whorl in section is de- 

 pressed, semilunar, the abdomen broadest, and there are costae 

 from an early stage of growth. The ventral is undivided accord- 

 ing to Sandberger's figures, and the funnel lobes break the suture 

 with a peculiar tubular prolongation of the tips of the lobes, and 

 with slight shoulders or minute incipient saddles on either side, 

 like those in the undivided ventrals of Brancoceras. These are 

 transitional to the minute siphonal saddles observed in the ven- 

 tral lobes of Triainoceras, present in the lower Devonian forms. 

 The species are Sandb. (Gon.) tuberculosocostatum, sp. Sand. 

 Verst. JSTass., pi. 4, fig. 1 ; and Sandb. (Gon.) Chemungense, sp. 

 Hall, Nat. Hist., N. Y., Vol. 5, pt. 2, pis. 69 and 74. The last 

 species has sutures which show it to be closely allied to Prole- 

 canites. Though very simple in outline, they would not have 

 been sufficient to separate it from Prolecanites but for the pres- 

 ence of costaticns on the whorls. 



Beloceras, 2 nobis, includes only one species but the most 

 remarkable and in many characteristics the most instructive of 

 Devonian forms. The additional lobes and saddles are very 

 numerous and have entire margins and are apparently only limited 

 in number by the breadth of the whorl. They are partly derived 

 from division of the ventral or primitive ventral saddles, and 

 partly from the division of the magnosellarian or umbilical saddles. 

 It must also be observed that here as in other forms the primitive 

 pair of lateral lobes are marked by their greater size, and their 

 earlier development. 



Sandberger has traced the mode of genesis of the lobes and 

 saddles in his text and in figure of Beloc. (Gon.) multilobatum, 

 sp. Beyr., and Branco, Paleontogr., Vol. 27, ser. 3, pi. 6, fig. 6, 

 has shown the process in its earlier stages. His figures and state- 

 ments, however, do not make it perfectly clear, that the first pair 

 of saddles are true primitive saddles, though they certainly seem 

 to have a close resemblance to those of Maenoc. bifer. Mojsiso- 

 vics in his " Gebirge um Hallstatt, p. 43 and 69 refers the type of 



2 BeXos, an arrow. 



