POINTS IN THE ANATOMY OF PERIPATUS CAPENSIS. 659 



The following is a summary of the fresh points "I have 

 observed in the nervous system : 



(1) Immediately underneath the oesophagus the oesophageal 

 commissures dilate and form a pair of ganglia equivalent to the 

 annelidan and arthropodan suboesophageal ganglia. These 

 ganglia are closely approximated and united by 5 or 6 com- 

 missures. They give off large nerves to the oral papillae. 



(2) The ventral nerve cords are covered on their ventral 

 side by a thick ganglionic layer 1 , and at each pair of feet they 

 dilate into a small but distinct ganglionic swelling. From each 

 ganglionic swelling are given off a pair of large nerves 2 to the 

 feet; and the ganglionic swellings of the two cords are connected 

 together by a pair of commissures containing ganglion cells*. 

 The other commissures connecting the two cords together do 

 not contain ganglion cells. 



The chief feature in which Peripatus was supposed to differ 

 from normal Arthropoda and Annelida, viz. the absence of 

 ganglia on the ventral cords, does not really exist. In other 

 particulars, as in the amount of nerve cells in the ventral cords 

 and the completeness of the commissural connections between 

 the two cords, &c., the organisation of the nervous system of 

 Peripatus ranks distinctly high. The nervous system lies within 

 the circular and longitudinal muscles, and is thus not in 

 proximity with the skin. In this respect also Peripatus shews 

 no signs of a primitive condition of the nervous system. 



A median nerve is given off from the posterior border of the 

 supracesophageal ganglion to the oesophagus, which probably 

 forms a rudimentary sympathetic system. I believe also that I 

 have found traces of a paired sympathetic system. 



The organ doubtfully spoken of by Mr Moseley as a fat body, 

 and by Grube as a lateral canal, is in reality a glandular tube, 

 lined by beautiful columnar cells containing secretion globules, 

 which opens by means of a non-glandular duct into the mouth. 

 It lies close above the ventral nerve cords in a lateral com- 



1 This was known to Grube, loc. cit. 



2 These nerves were noticed by Milne-Edwards, but Grube failed to observe that 

 they were much larger than the nerves given off between the feet. 



3 These commissures were perhaps observed by Saenger, loc. cit. 



