170 



Two very different shells have been placed under the 

 genus ellipsolithes (Sowerby), both oval and discoidal shells; 

 but one possessing the involved whirls and the plain septa 

 of nautilus, and the other the whirls, apparent on both sides, 

 and the winding septa of ammonites. It being desirable 

 that the student should be apprised of the forms and cha- 

 racters of these fossils, their figures and a description of 

 their characters are given ; but although, for the sake of 

 discrimination, a name is added to each, it is not intended 

 to urge a claim for their being considered as distinct genera. 

 In this I am glad to concur with Mr. Sowerby, who ob- 

 serves, that " The genus ellipsolithes must certainly be 

 abolished, and its species ranged under ammonites, the oval 

 form being quite accidental." 



5. Nautellipsites. A multilocular, tumidly discoidal and 

 elliptically spiral shell ; the turns contiguous, the outer one 

 including the others ; situation of the siphuncle nearly 

 central. Fossil. PI. vi. fig. 3. 



6. Ammonellipsites. A multilocular, flatly discoidal and 

 elliptically spiral shell ; the turns contiguous and apparent 

 on both sides ; the chambers separated by winding septa ; 

 the siphuncle marginal. Fossil. PI. vi. fig. 4. 



7. Nummulites. A multilocular, lenticular shell; the 

 spire internal, formed of several plates, connected with each 

 other on both sides by numerous transverse septa, the in- 

 ternal plates being involved by the more external. Fossil. 

 PI. vi. fig. 5. 



8. Siderolites. A flattish, multilocular shell, convex 

 above and beneath, set with pointed tubercles, with four or 

 five short unequal rays on the edge, not manifesting any pores. 



An idea of this fossil may be formed by considering the 

 radiating appendices as proceeding from bodies like the 

 nummulites. Faujas St. Fond, who has given the best re- 

 presentation of these bodies, delineates them as being mul- 

 tilocular, somewhat like the nummulites. 



