ANALYSIS OF THE LESSONS. 



Continued. 1116. Concluded. 1117. The motor nerves first described by 

 Lyonnet. 1118. Limulus polyphemus described ; its agreement with insects. 



LESSON LXXV. NERVOUS SYSTEM OF INSECTS, CONTINUED, .... p. 247. 

 1119. Segmented condition of the lower Articulata. 1 1 20. Analysis of these 

 segments. 1121. Position of the ganglia relatively to the segments. 1122. The 

 brain of a Caterpillar described. 1123. The recurrent (sympathetic) nerve. 

 1124. Method of connecting the divided brain. 1125. Necessity for the pecu- 

 liar position of each portion of the brain. 1126. Character of the nerves aris- 

 ing from the inferior portion of the brain. 1127. First thoracic ganglion. 

 1128. Second and third thoracic ganglions. 1129. The position of the arteries, 

 misnamed respiratory nerves, described. 1130. The caudal ganglia. 1131. 

 Other reference to the brain of this caterpillar. 1132. Condition of the ganglia 

 in the larval state of insects. 1133. Their condition in the perfect insect. 

 1184. Description of the nervous system in Blatta Americana. 



LESSON LXXVI. NERVOUS SYSTEM IN ARACHNIDA, p. 251. 



1135. The class described its position. 1136. In these animals the ner- 

 vous system is concentrated ; the heart and respiratory organs better de- 

 veloped. 1137. No metamorphosis. 1138. The cephalo-thorax. 1139. Num- 

 ber of their legs. 1140. Number of legs in Crustacea. 1141. Majority air 

 breathing. 1142. The Mites. 1143. The Demodex folliculorum. 1144. The 

 itch, and the mange what causes them. 1145. The Acarus scabicei. 1146. 

 Nature of the itch who are affected by it. 1147. Nervous system in the 

 Mites, not known; the nervous system in Scorpions. 1148. Description of it. 

 1149. The same in Spiders. 



LESSON LXXVIL NERVOUS SYSTEM IN THE MOLLUSCA, p. 253. 



1150. Differs from the Articulata. 1151. Nervous system unsymmetrical. 

 1152. Its condition in Articulata. 1153. The like in Mollusca. 1154. Its ad- 

 vance of development in Insects. 1155. Comparison with Mollusca. 1156. 

 Why so called. 1157. Many of them headless. 1168. THE TUNICATA its 

 nervous system. 1159. The Salpae. 1160. General description. 1161. Salpa 

 polycratica. Its nervous system. 1162. Is the Salpa a perfect animal ? 



LESSON LXXYIII. NERVOUS SYSTEM IN THE BRACHIOPODA, ... p. 256. 



1163. Brachiopods: definition. 1164. Terebratula Australis described. 

 1165. Its habits. 1166. The mantle. 1167. The respiratory apparatus. 1168. 

 Respiration : how performed. 1169. The arms. 1170. Continued. 1171. The 

 alimentary canal. 1172. The vascular system. 1173. The nervous system. 

 1174. The muscles. 1175. The pedicle. 1176. Remarks. 



LESSON LXXIX. -NERVOUS SYSTEM OF THE LAMELLIBRANCHIATA, . . p. 259. 



1177. Nature of the shell of the Brachiopods. 1178. The like in the Lamel- 

 libranchiata. 1179. Their nervous system. 1180. The branchial ganglion. 

 1181. The nervous system in Mytilus edulis described. 1182. The ganglionic 

 centres. 1183. Their mode of connection. 1184. The cephalic ganglions. 



