578 FRANK E. BEDDAED. 



shows the continuity between the subneural pouch and the 

 body-cavity ; the walls are seen to be formed from the interseg- 

 mental Septum 13/14, and form a membrane (S), which, traced 

 backwards, comes into continuity with intersegmental Septum 

 14/15. In the second section (fig. 5) the two membranes join 

 above the subneural pouch ; the third section (fig. 6) is through 

 the ventral median line, and the nerve-cord is, therefore, indi- 

 cated. The subneural pouch is seen to lie below the nerve- 

 cord, and in contact with the longitudinal muscular coat of the 

 integument ; the intersegmental Septum 13/14 does not reach 

 the nerve-cord, and to its free extremity is attached the mem- 

 brane uniting it with the following intersegmental septum. 

 In this specimen the epidermis lying immediately below the 

 subneural pouch is exactly like the epidermis elsewhere, i. e. 

 the glandular cells are not absent. It will, I hope, be clear 

 from the above description and from the figures that the sper- 

 mathecal sac is first of all formed by certain membranes in the 

 ccelom, which become approximated and attached in parts to 

 form a sac. Later on the sac burrows its way towards the 

 exterior, where it appears to be met by a very limited invagi- 

 nation of the epidermis. This mode of formation has a remark- 

 able analogy to the formation of the oviducts in certain ganoid 

 and teleostean fishes. It is very probable that, as I have 

 already suggested, the second oviduct in Eudrilus is formed 

 in a similar way. It will be observed that in early stages the 

 ovary comes to lie within the spermathecal sac. If, for some 

 reason or other, the backward extension of the sac were 

 checked, it would form simply a duct for the ova. 



There is also an interesting analogy to the formation of the 

 nephridia and genital ducts in Peripatus, which have been 

 recently so successfully investigated by Mr. Sedgwick. 



In a species of Moniligaster — M. Houteni — Dr. Horst 

 has described the oviduct in a way which suggests that 

 it resembles the early stage of the spermathecal sac of Li by o- 

 drilus. His description (13, p. 99) is as follows: — ''As 

 stated before, the 12th and 13th septa are placed close 

 against each other ; these two septa seem to form together on 



