254 FRANK E. BEDDARD. 



"Thamnodrilus" G-ulielmi (really a Rhinodrilus, as I 

 pointed out later), and the figures published in illustration of 

 that description, bear out^ so far as they go, M. Vaillant's 

 opinion, and are not confirmatory of the earlier view of M. 

 Perrier. I figured (loc. cit., p. 157, fig. 2) a conical body 

 protruding from the mouth aperture, and surrounded by 

 that orifice, which evidently corresponds to the structure 

 described here in Trichochseta. As this process is not 

 attached to the first segment of the body, I stated that 

 there was no prostomium. The resemblance in this par- 

 ticular between Ehinodrilus and Trichochseta is, of 

 course, of additional interest, inasmuch as they both belong 

 to the same family of earthworms. A protrusible pro- 

 boscis of this kind is not found in any other Oligochtetous 

 Annelid. It must be noticed that it is not a diverticulum 

 of the pharynx, but of the buccal cavity, though arising close 

 to the junction of the two sections of the gut. Both buccal 

 cavity and pharynx belong, it must be remembered, to the 

 stomodseum. 



The epidermis presents the usual characters. The peculiar 

 refractive bodies found in the epidermis ofPontoscolex, and 

 so distinctive of that genus, are entirely absent. If a portion 

 of the dermo-muscular tube be mounted in glycerine, and 

 the difi'erent layers be successively brought into focus, the 

 following is the appearance of the difi'erent structures : — The 

 epidermis appears to consist of large nucleated polygonal cells 

 only; these are, however, the gland-cells, between which lie 

 the interstitial cells, forming a meshwork. Bringing the 

 circular muscular layer into view, its fibres are seen to be 

 limited to the anterior and posterior borders of each segment, 

 leaving the middle free, or traversed by a few fibres only, 

 which give the appearance of a loose meshwork. The longitu- 

 dinal layer beneath this forms a nearly continuous sheet, 

 broken only by the implantation of the setas. In transverse 

 sections the spaces in the circular muscular layer are seen to 

 be filled with a granular substance containing interspersed 

 nuclei. We have evidently to do with an exaggerated de- 



