548 MANUAL OF NATURAL HISTORY. 



curious Homalonotus of tlve Ludlow limestones, with 

 its abdomen ending in a long point, and the Caly- 

 mene, or " Dudley-Locust/' with large trilobate 

 head, besides Cyphaspis, Phacops, and (Eonia, other 

 members of the Calymenidce. In the Harpidce, 

 where the sides of the segments are rounded, and 

 the surface of the body is furrowed, we find the 

 Ellipsocephalus, Harpes, and Conchocepkalus, and 

 among the Olenidce, which were unable to roll 

 themselves into a ball, we include, besides Olenus, 

 the singular Paradoxides, with the lateral segments 

 ending in long deflexed spines. Brontes was an- 

 other remarkable form, having the lateral portions of 

 the abdominal sections radiating and forming a fan- 

 shaped expansion; this genus, with ftveOdontopleurce 

 and Arges formed another family (Odontopleuridce), 

 the members of which were also unable to roll them- 

 selves up. Among the Ogygiidce, we find the Trinu- 

 cleus, with the margin of the cephalic segment per- 

 forated, and Ogygia with the same part prolonged 

 on each side into slender spines distinct from the 

 body, and the family of Eurypteridce, which were 

 furnished with antennae. Tentaculites, the tube of 

 an Annelid allied to Serpula, is the only repre- 

 sentative of other annulose animals ; it is found 

 in the Caradoc sandstone of the Lower Silurian 

 strata. 



Among Cephalopadous Mollusks the genera P/^ra*/- 

 moceras and Lituites have been observed, but these 

 chambered forms are very limited in number and 

 size compared with their abundance, and the gigantic 



