333 



'illese organs have not completely escaped the attention of previous 

 observers. The anterior of them were noticed by Grube 3 ), but their 

 relations were not made out. By S a enger 4 ], as I gather from 

 Leuckart's Bericht for the years 186S/69, these structures were also 

 noticed, and they were interpreted as segmental organs. Their external 

 openings were correctly identified. They are not mentioned by Mo- 

 seley, and no notice of them is to be found in the text-books. The 

 observations of Grube and Sanger seem, in fact, to have been com- 

 pletely forgotten. 



The organs are placed at the bases of the feet in two lateral divi- 

 sions of the body-cavity shut off from the main median division of the 

 body-cavity by longitudinal septa of transverse muscles. 



Each fully developed organ consists of three parts : 

 l ì A dilated vesicle opening externally at the base of a foot. 



(2) A coiled glandular tube connected with this , and subdivided 

 again into several minor divisions. 



(3) A short terminal portion opening at one extremity into the 

 coiled tube (2) and at the other, as I believe, into the body-cavity. 

 This section becomes very conspicuous in stained preparations by the 

 intensity with which the nuclei of its walls absorb the colouring matter. 



The segmental organs of Pcripatus, though formed on a type of 

 their own, more nearly resemble those of the Leech than of any other 

 form with which 1 am acquainted. The annelidan affinities shown by 

 their presence are of some interest. Around the segmental organs in 

 the feet are peculiar cells richly supplied with tracheae, which appear 

 to me to be similar to the fat bodies in insects. There are two glan- 

 dular bodies in the feet in addition to the segmental organs; both 

 of which have their external openings on the ventral surface of the feet. 



The more obvious features of the nervous system have been fully 

 made out by previous observers, who have shown that it consists of 

 large paired supraoesophageal ganglia connected with two widely se- 

 parated ventral cords, — stated by them not to be ganglionated. 

 Grube describes the two cords as falling into one another behind the 

 anus — a feature the presence of which is erroneously denied by 

 Saenger. The lateral cords are united by numerous (5 or 6 for each 

 segment) transverse cords. 



The nervous system would appear at first sight to be very lowly or- 

 ganized, but the new points I believe myself to have made out, as well 

 as certain previously known features in it, appear to me to show that 

 this is not the case. 



3) »Bau von Perip. Edwardnii« , Archiv f. Anat. u. Phys. 1853. 

 4i Moskauer Naturforscher-Sammlung, Abth. Zool., IS(iî). 



