DESCRIPTION OF PLATES. XV11 



FIG. PAGE 



160. Scrupularia scruposa, with bird's-head processes 



(avicularia) and sweeping bristles (vibracula). . 73 



161. Snake-headed zoophyte Anguinaria 78 



162. Flustra foliacease& mat 72 



168. Plumatclla repens, a fresh-water polyzoon 74 



164. Egg of Cristatdla Mucedo, a fresh-water polyzoon 74 



165. Transverse section of shell of Pinna, showing 1 



prismatic shell structure 74 



166. Longitudinal section of shell of Pinna 75 



167. Transverse section from oyster-shell 75 



168. Section of shell of Anomia, with tubular borings. . 75 



169. Section of mother of pearl 75 



170. Prawn-shell viewed as a transparent object 75 



171. Teeth of whelk 75 



172. Teeth of limpet 75 



173. Teeth of periwinkle 75 



174. Teeth of Limneus 75 



175. Scale of sturgeon ganoid >JQ 



176. Prickle from back of skate placoid yg 



177. Borings by a minute parasite in a fossil fish-scale. . 77 



178. Scale of sole ctenoid ; 77 



179. Scale of whiting cycloid * 



a. Calcareous particles, magnified. 



180. Scale of sprat cycloid 7V 



181. Section of egg-shell 90 



182. From soft egg. 



183. Section of egg-shell of emu, 90 



PLATE VI E. to face page 80. 



IS I. Human hair > 73 



a- Transverse section of human hair. 



