two NEW SPKCIES OF ONYCHOPHORA. 515 



present juncture it is proposed to examine the known facts 

 of anatomy and development in order to see how far such a 

 statement is justified. 



Gaffron's description of the "au;il glands" of P. Ed- 

 war dsii, and AVilley's account of the "pygidial glands" of 

 P. Nova3- Britan nitc are in agreement in so far as that 

 they show that the glands consist of two parts, Avhich Gaffron 

 designated the "ectodermal" and the " entodermal'*' por- 

 tions, and which Willey describes as " ectodermal " and 

 "mesodermal." The same distinction occurs in Eoperipa- 

 tus, though it is perhaps not so well marked. So far, then, 

 there is in these three genera an agreement between the acces- 

 sory glands — to use one term for all of them — and the renal 

 organs, which consist of an ectodermal portion, however 

 short, and a mesodermal or ccelomic portion. It must be 

 pointed out, however, that too much importnuce should not 

 be attached to the difference between the so-called ecto- 

 dermal and mesodermal portions of these glands, because 

 the lining cells of the ccelomic portions of the renal organs 

 differ widely from one part to another; for example, the 

 lining of the funnel differs more from that of the coiled tube 

 or of the ccelomic end-sac than the lining of the two parts of 

 the accessory glands do from one another. It follows that the 

 argument derived from histology in favour of the view that 

 the accessory glands consist of ectodermal and mesodermal 

 parts homologous with the similarly situated parts of the renal 

 organs is not a very strong one. It seems that the only point 

 of any importance is the existence of a chitinous intima lining 

 the so-called ectodermal portions, whicli are ahvays short. 



Kennel described the development of the anal glands in 

 P. Edwardsii as taking place from the apod;il anal seg- 

 ment ; that is, the second segment behind the genital one, 

 and also found a vestigial representative of f/hem in the 

 young female. The conclusion which naturally follows is 

 that the anal glands of P. Edwardsii are homologous with 

 the renal organs and genital ducts. 



In Peripatoides Nova3-Zealaudiae the accessory 



