NERVOUS SYSTEM. INVERTEBRATA. 



31 



D. 



23. A Pcntastomum tcenioides, in which parts of the 

 nervous system are shown from above (fig. 14). The 

 central system is in a degenerate condition ; it consists of 

 a bilobed ganglionic mass, situated behind the oesophagus. 

 Its lateral parts are united in front of the oesophagus by a 

 delicate commissure, in which there is no sign of a pra?- 

 oral ganglion. The ganglionic mass gives rise from its 

 posterior surface to a pair of longitudinal nerves of some 



Fig. 14. 



The Nervous System of Pentastomum teemoidcs, after Leuckart. 



0. Prse-oral commissure. G. Ganglion. L.C. Longitudinal cords. 

 (ES. (Esophagus. 



size that extend to the hinder part of the body; it also 



gives off from its anterior and lateral regions several small 



nerves to the alimentary canal, body-muscles, and cephalic 



hooks and papillae. The specimen shows little beyond the 



main ganglionic mass. 0. 0. 1294 c. 



Spencer, Quart. Journ. Micr. Sci., vol. xxxiv. 1893 ? 



p. 33. 



MYRIAPODA. 



D. 24. Two specimens of the nervous system of a Centipede 

 (Ethmottig mus rubripes). The central system shows the 

 Arthropod type in a very simple condition ; it consists of 



