72 AMMONITID^. 



the body-chamber. Impressions of the mantle attachment punc- 

 tate or striate. Wrinkled layer consisting of broken-up striae. 

 The sutural line of the septa is distinguished by the presence of 

 external adventitious lobes. Three groups of lobes may accord- 

 ingly be distinguished : 1. The adventitious lobes. 2. The three 

 principal lobes. 3. The auxiliary lobes. The adventitious and 

 auxiliary lobes always present a similar structure, whilst the 

 principal lobes frequently present a peculiar form. 



Sageceras, Mojs., 1873. 



Distr. — 7 sp. Permian and Triassic. Sageceras Haidingeri^ 

 Hauer (xl, 48, 49j. 



Close to Pinacoceras in the form of the shell and length of 

 the body-chamber, and differs from it in the structure of the 

 wrinkled layer, the form of the lobes and the direction of the 

 lines of growth in the concave portion. The wrinkled layer is 

 coarsely granular, as in Nautilus, and does not consist of long- 

 striae and threads, as in the Arcestae. The saddles are slender, 

 narrow, tongue-like, entire, the lobes symmetrically divided, 

 simply or doubly, b}^ simple conical teeth. Three groups of lobes, 

 as in Pinacoceras. The lines of growth do not trend backwards, 

 as in Pinacoceras, but forwards. 



Sageceras is already fully developed in the Permian formations, 

 though in these older forms the siphonal process characteristic 

 of the Ammonite stage is wanting. 



NOViTES, Mojs., 1878. Wrinkled layer striated; an adventive 

 saddle not reaching the height of the first principal saddle ; saddles 

 narrow, elevated, rounded at their superior extremity ; lobes but 

 little truncate; first principal lobe divided. S. Gaprilensis, Mojs. 



MEDLicOTTiA, Waagen, 1880. Siphonal side (periphery) either 

 excavated and rounded on both sides by high and sharp crests, 

 or simply flattened, and defined on both sides by angular margins. 

 In both cases the high and narrow saddles developed on each 

 side of the siphonal lobe are situated exactly below the crests 

 or the angulated margins ; these saddles are strongly serrated 

 from both sides, and the denticulations of the opposite sides of 

 the saddle correspond exactly with each other. M. Wynnei, 

 Waagen (xxxix, 43, 44). Productus Limestone (Carboniferous) ; 

 India. 



Otooeras, Griesbach, 1881. 



Distr.' — 0. Woodioardi, Griesb. (xxxix, 40-42). L. Triassic ; 

 Himalayas. 



Shell involute, with very deep umbilicus, and rapidly increasing 

 outer whorls ; the part nearest the umbilicus bulged out into an 

 ear-like shape, giving the section of the shell a more or less 

 rhomboidal aspect. It is very probable that in adult individuals 

 the last whorl covered and enclosed the entire preceding shell. 



