46 



POPULAR COXCHOLOGY. 



are in general like the Ammonites, with six unequal lobes, 

 which consist of very long unequal parts ; the siphuncle 

 dorsal and connected. — 38 species, fossil. 



H amite s. Parkinson. — Shell many-chambered, rolled 

 on the same plane, but 

 irregularly spiral ; the 

 spire being extremely 

 elliptic, strongly bent at 

 both ends, and between 

 these parts straight or 

 but slightly curved : the partition walls symmetrical, con- 

 sisting of six very unequal lobes, of which the upper 

 side-lobe is split into two equal parts; dorsal lobe very 

 short. — 58 species, fossil. 



Sowerby represents some very large species in " Mineral 

 Conchology," particularly H. grandis, which is as thick as 

 a child's arm, and another which is remarkable from being 

 :t with spines at the outer edge three eighths of an 

 inch long ; it is of large size, found in chalk-marl in Ox- 

 fordshire, and named H. armatus. 



Pttchoceras. D' Orb. — ^/^//many-chambered; round 

 or compressed ; not spiral ; bent back upon itself so that 



Ptpchoceras Emeriaanxim. 



the last part is in contact with the preceding the whole 

 Length : the partitions symmetrical, with six slightly 

 unequal lobes, of which the upper side-lobe is divided 

 equally ; the dorsal lobe the longest the siphuncle dorsal 

 and connected. — 7 species, fossil. 



