1883.] 



329 [Hyatt. 



Notwithstanding the extraordinary development of the si phonal 

 saddles, there is no corresponding division in the annular lobe, 

 which is subacute and entire in outline. The first pair of saddles 

 have corresponding but smaller and less acute saddles on the dor- 

 sum, and the magnosellarian saddle is also nearly as prominent as 

 on the venter. The umbilical shoulders are occupied by rounded, 

 lobes. All the known species are found in the Carboniferous and 

 have the pyramidal form of siphonal saddle. The funnels are 

 surmounted by collars which can be seen on good casts of Glyph, 

 sphaericum and which closely simulate the collars of Schistoceras. 1 

 It seems evident that Prionoceras is the intermedium between 

 this genus and the common family radical, Brancoceras. The 

 young of Glyp. obtusum, as figured by DeKon. Calc. Carb. pi. 47, 

 shows the relation of the group to the more remote radical Par- 

 odiceras with which the sutures agree quite closely except in the 

 siphonal saddle. 



Glyph. (Gon.) crenistria, sp. Phill. Foss. Corn. Devon, pi. 50, fig. 

 234, spiralis, Rom. Nordwest-Harzegeb. Paleontoger. Vol. 3, pi. 

 8, fig. 15, carbonarium, Buch. Ueber Goniat. pi. 2, fig. 9, sphaeri- 

 cum, Calc. Carbon., pi. 47, fig. 3-5, striatum, Sow. Min. Conch., 

 trans., pi. 53, fig. 1, striolatum, Phill. Geol. York. pt. 2, pi. 19, fig. 

 14-19, truncatum, Rom., Nordwest-Harzegeb. Paleontogr. Yol. 3, 

 pi. 13, fig. 30. The shells in this section of the genus are involute 

 but the umbilici open, and the whorl semilunar in section. The 

 ventral lobe has a distinct siphonal saddle, which divides it into 

 two acute terminations, the first pair of lateral saddles are inclined 

 towards the umbilicus, and often acute, first pair of lateral lobes 

 also acute, the magnosellarian saddles are undivided. 



The second section includes the following, Glyph. (Gon.) 

 obtusum, sp. Phill. Geol. York. pt. 2, pi. 19, fig. 10-13, micronotum, 

 ibid, pi. 19, fig. 22, 23, platylobum, ibid, pi, 20, fig. 5, 6, stenolobum, 

 ibid, pi. 20, fig. 7-9, Barbotanum. M. V.K., Russ. and Ural, pi. 27, 

 fig. 3, diadema, ibid, pi. 27, fig. 1, complicatum, Kon. Calc. Carbon. 

 pi. 50, fig. 4, nitidum Phill. ibid. pi. 20, fig. 10-12. These shells 

 have similar sutures, but the saddles are often slightly rounded or 

 linguiform, and the whorls compressed. The siphonal saddles are 

 smaller, and larval in shape and proportion. All of the first list 

 except spiralis occur in the lowest beds of the Carboniferous, and 



1 See also p. 315, and p. 336. 



