I'WO NEW SPECtES OF ONYCHOPHORA. 5l3 



nearer the base of the Onychophovoa branch of the great 

 Arthrojiodan phylum than the African, New Zealand, 

 and Australian genera. This agrees with the arrangement 

 to which we are forced on other grouuds, which will be dis- 

 cussed later. 



{(j) The Male Accessory Glands. — These are a pair of 

 glands which occur only in the male (fig. 35, m. a. g., 

 and fig, 36, m. a. g.). Their external opening has already 

 been described (p. 490). The general course which they take 

 is the following. They start as straight tubes, occupying a 

 cavity of their own situated in the dorso-lateral aspect of 

 the body. Their position is shown in tig. 35, which repre- 

 sents a transverse section passing just in front of the male 

 genital pore, from the level of which they pass obliquely 

 downwards on the outer side of the nerve cords to the 

 common opening which is situated between the last pair of 

 legs. In passing round the nerve cords they press against 

 them in such a way as to become partially embedded in 

 them. 



The inner ends of the male accessory glands have thin 

 walls and a fairly large lumen, which is circular in shape 

 (fig. m. a. g.), and which is not lined by a chitinous 

 intima. The lining cells of this part are short and colum- 

 nar ; the peritoneal investment consists of much-flattened 

 cells, and the intervening layer is thin. The walls of the 

 portion situated nearer to the exterior which passes round 

 the nerve cords are much thicker, and the lumen, which may 

 be of any shape, and small, is lined with a chitinous intima. 

 It consists of the same three layers as the thinner portion 

 situated more internally, but the middle or muscular layer is 

 much thicker. 



It is difiicult to say what the homology of these glands 

 may be, as their development has not been worked out ; but 

 it seems necessary to discuss the possibilities of the question, 

 were it only to clear the ground. The great difficulty of the 

 subject lies in the different positions occupied by the ex- 

 ternal openings of a pair of glands which are found more or 



