THE MALAYAN SPECIES OF ONYCHOPHOKA. 67 



is in error in deriving almost the whole of the oviducts from 

 the ectoderm ; for all the convolutions, which appear later 

 on in the development, are the result of growth in the inner 

 part of the oviducts and not in the outer. 



The Receptaculum Ovoram. — The receptaculum 

 ovorum ai-ises as a simple evagination on one side — usually 

 the dorsal side — of the oviducal wall (PI. 8, fig. 17 c, re. o.). 

 The evagination in question elongates, and the wall at its 

 free end becomes thinner, so as to form a membrane, which 

 closes its distal end (PI. 9, figs. 26 a, 26 6, 26 c, 26 1^, and 

 26 e). The whole organ is merely a local growth which 

 appears relatively late, and for these reasons I am inclined 

 to reject the suggestion made by Mr. Sedgwick, and adopted 

 in the first part of my account of Eoperipatus, that the re- 

 ceptaculum ovorum is homologous with the renal end-sac (2). 



The Receptaculum Seminis. — The development of the 

 receptaculum seminis has been described by Gaffron (3), 

 whose account is essentially correct. In Eoperipatus each 

 oviduct forms a loop (PI. 9, fig. 26 a, re. s.). The canal, at 

 the free end of the loop, begins to expand (PI. 9, fig. 26 fo, 

 re. s.), and the cavity of the receptaculum seminis forms by 

 the continued enlargement of this part (PI. 9, figs. 26 c, 26 d, 

 and 26 e, re. s.). The lateral portions of the loop become the 

 narrow ducts of the receptaculum seminis and always remain 

 embedded in its wall, which is much thinner than Avas re- 

 presented by Gaffron, who described in the genus Peripa- 

 tus a thick middle layer, a layer which in Eoperipatus 

 is extremely thin. Gaffron also figures the openings of 

 the ducts into the receptaculum seminis as situated close 

 together, while in Eoperipatus they are placed on opposite 

 sides (PL 9, fig. 26 e). At first there is no communica- 

 tion between the two portions of the main canal, save by 

 way of the loop, which gives rise to the receptaculum 

 seminis and its ducts ; but later on the septum, at first 

 thick (PL 9, fig. 26 h), becomes thinner (PL 9, figs. 26 c 

 and 26 d) and ultimately disappears (PL 9, fig. 26 e). At 

 first the lining of the canals, situated on either side of the 



