PLATE VI. 



Colours: see Plate I. 



Figs. 180 — 203. Chaetoderma Lovéni. 



Figs. 180, 181. Chaetoderma Lovéni, drawn from spirit-specimens. 4 X. 



Fig. 182. Posterior extremity with the long straight spicula. 37 X. 



Fio-. 183. Spicula 75 X. A of the body-wall, B around the mouth-opening, C oi the posterior extremity. 



Fig. 184. Section through the integument. 125 X. R "Riesenzellen". 



Fig. 185. Section through the integument of the middle region. 215 X. 



Figs. 186 — 190. Schematic transverse sections through the anterior extremity. c "Mundschild", a see text, 



m lateral, 111' dorsal, m" ventral retractors. 30 X. 

 Fio-s. 191 — 192. Sections through the radula of one of the specimens. 215 X. See text. 

 Figs. 193 — 194. Sections through the radula of the other specimen. 215 X. See text. 

 Fig. 195. Schematic transverse section through the middle region of the animal. 30 X. / liver, 



i intestine. 

 Figs. 196 — 200. Schematic transverse sections through the posterior extremity. 39 X. g gills, g 111 gill- 



protractor, vr ventral retractors, dr dorsal retractors, Ir lateral retractors, gps ganglion 



posterius superius. 

 Fig. 201. Section through the pericardium, in which the ganglion posterius superius G.p.s. a atrium, 



dr dorsal retractors. 75 X. 

 Figs. 202, 203. Sections through the cerebral ganglion hg, 3, ./, 3, 6 lateral ganglia, /, 2 proximal 



ganglia. 50 X. 



Figs. 204 — 210. Chaetoderma Wiréni. 



Fig. 204. Chaetoderma Wiréni, drawn from the spirit-specimen. 4 X. 



Fig. 205. Spicula. 75 A of the body-wall, B of the posterior extremity, C around the mouth-opening. 



Figs. 206, 207. Schematic transverse sections through the anterior part 29 X. m' dorsal retractors, m lateral 



retractors, m" ventral retractors. 

 Fig. 208. Section through the integument. 125 X. 



Figs. 209, 210. Sections through the radula. 215 -X- See text. 



Figs. 211 — 216. 



Fig. 211. Radula of Chaetoderma canadense. 215 X. See text. 



Figs. 212, 213. Radula of Chaetoderma sp. (NORMAN). 388 •'. See text. te tongue-cartilage, m muscle, 



sg sublingual ganglion, E ciliated epithelium of the pharynx. 

 Figs. 214, 215. Radula of Chaetoderma sp. (= Chaetoderma Lovéni). 215 X. See text. 

 Fig. 216. Radula of Chaetoderma nitidulum. 215 X. See text. 



