Hyatt.] 332 TApril 4, 



lobes in adults exclusive of the inner series of auxiliary lobes and 

 saddles. One pair of lateral lobes, the outer pair of the adult 

 stages, arises out of the division of the first pair of saddles in Pro- 

 lecanites, and several pairs in Beloceras, but whether this may be 

 considered exclusively the method of generation cannot be stated 

 now. The primitive pair of lateral lobes are generally deepest 

 and may be distinguished by this character. The general form of 

 the matured lobes is hastate and the saddles club-shaped, but the 

 Belocerae,the lowest or radical sub-family, and the lower or rad- 

 ical species of Triainoceras have simple flexuous outlines in the 

 sutures. The ventral lobes are, as in other families, undivided in 

 radical genera and species ; and divided in higher forms of each 

 tribe or sub-family group. The first pair of saddles have corres- 

 ponding sad. lies on the dorsum, and there are deep, undivided, 

 annular lobes. The dorsal suture is divided not only by this pair 

 of saddles, but has additional pairs corresponding closely to the 

 number of saddles and lobes on the exterior in all the broad 

 whorled genera ; except the umbilical lobes, which as in all the 

 Goniatitinae have no correspondents. The radical genera appear 

 to approximate to Sandbergeoceras and this genus is not trace- 

 able to Parodiceras, so far as we know. The other radical forms, 

 however, like Sandbergeoceras Cnemungense and Phar. tridens 

 have lobes and saddles, which indicate derivation from Magnosel- 

 jaridae, and we have accordingly referred the group provisionally 

 to this radical. This family is very interesting also, because we 

 can directly trace a connection with Jurassic forms, and see that 

 the phy lliform marginal saddles of Lytoceras and Phylloceras are 

 probably derived through Monophyllites of the Trias from Prole- 

 canitidae. The line is evidently an unbroken one to Ptychites and 

 we think these and the Phylloceratidae can be distinguished by 

 the excessive division of the lobes, the attenuated and deeply cut 

 saddles and the peculiar form of the siphonal saddles and their 

 close relations to the first pair of saddles taken in connection with 

 the phylliform marginal saddles, and the tendency to produce ad- 

 ditional external saddles, and lobes, and numerous auxiliary lobes 

 and saddles. We shall probably in forthcoming publications sep- 

 arate this whole series, including Arcestes from the Ammoni- 

 tinae and Goniatitinae, under the name of Prolecanitinae. 



