34 



CONAEIO-HIPOPHTSIAL TRACT. 



which, by the course of the oesophagus, c, in Mollusks and 

 Articulates, is turned to the haemal aspect of the alimentary 

 canal, is that which is usually designated the "supraoeso- 

 phageal ganglion," or, after Lyonnet and Cuvier*, ''the 

 brain." 



This consists of a pair of neural masses, or hemispheres," 

 confluent mesially for one half of their longitudinal extent, 

 before and behind which confluent tract they are free. Each 

 moiety presents three lobes or enlargements, the smallest of 

 which receives the antennal nerve (fig. 11, e), a second, the 

 largest, the optic nerve, / the third the oceflar nerve, yf. 

 I rom the oesophageal surface of each moiety proceeds the tract 

 or " commissure," d, which, traversing its own side of the 

 gullet, converges to and, with its fellow, expands into the 

 neural mass termed the " suboesophageal ganglion," b. 



With this neural mass are connected by origin or insertion 

 the nerves, h, i, of the " trophi," i. e. the labrum, the man- 

 dibles, the maxillae, the labium with its tongue-like extension, 

 and the sense-organs called " maxillary " and " labial palpi," 

 together with the complex muscles of these several parts. 



The properties of the vertebrate mouth, viz. taste and 

 motions, may be reasonably assigned to the foregoing inver- 

 tebrate oral organs : accordingly the nerves connected there- 

 with, endowing the mouth with the same characteristic powers 

 and properties for testing, seizing, and comminuting alimen- 

 tary substances, I deem, with their neural centres, to be 

 homologous with those of like endowments in the vertebrate 

 animals. 



* " Le cerveau proprement dit," Legons d'Anat. comparee, ed. 1845, 

 torn. iii. pp. 305, 335. 



-j- I omit the filaments connecting the foremost minute mesial ganglion 

 of the " sympathetic " or " stomato-gastric " system with the ahove 

 cerebral mass. 



