390 Mr. F. E. Beddard on the 



With regard to external characters the genus Pkreoryctes is 

 distinguished by two peculiarities. Both Leydig (" Ueber 

 Phreoryctes Menkeanus^' Arch, fur mikr. Anat. 1865) and 

 Timm (" Beobachtungen iiber Phreoryctes &c.," Arb. a. d. 

 Zool.-Zoot. Inst. Wiirzburg, Bd. vi. 1883) describe the set^e 

 of P. Menkeanus as disposed in four rows of a single seta 

 each. Vejdovsky (' System,' &c., p. ^9) states of the second 

 species, P.filformis, " Die Borsten steheninvier Beihen und 

 je einzeln in jedem Borsten-follikel ; doch in nicht seltenen 

 Fallen erscheint auch neben der alten Borste eine fast vollig 

 erwachsene Ersatzborste, so das es den Anschein hat, als ob 

 das betreffende Borstenblindel aus zwei Borsten zusammen- 

 gesetzt wiirde." It is therefore important to note that in 

 my species the setce are invariably paired ; their shape more- 

 over (PL XXIII. fig. 10) appears to be rather different from 

 that of the seta figured by Vejdovsky (' System/ &c. pi. xii. 



The second peculiarity of Phreoryctes is the incomplete 

 division of the prostomium into two rings by a transverse 

 furrow ; I have found this to be the case in my species 

 (PI. XXIII. fig. 2), and this is one of the chief reasons which 

 leads me to place my specimen in the genus Phreoryctes, with 

 which, moreover, it has apparently other points in common to 

 be referred to later. 



The arrangement of the pairs of setge with respect to 

 each other can be understood from an inspection of PL XXIII. 

 fig. 7, which represents a transverse section through one of 

 the posterior segments ; the two dorsal pairs are much nearer 

 to each other than are the two ventral pairs or the dorsal and 

 ventral pairs of one side. 



There is a marked difference in size between the dorsal and 

 ventral set£e, as is the case in P. fltformis, the dorsal being 

 far stouter. This is, however, not the case in tlie anterior 

 segments of the body. 



The facts in the internal structure of the worm, to which I 

 wish to direct attention in the present paper, concern the 

 reproductive organs and their ducts (PL XXIII. fig. 3). 



Our knowledge of these is at present extremely limited. 

 Vejdovsky was unable to find any trace of the reproductive 

 organs in P. fliformis. Leydig and Timm have, however, 

 given some details with respect to P. Menkeanus. There 

 are said to be four pairs of testes lying in segments ten, eleven, 

 twelve, and thirteen (the ninth, tenth, eleventh, and twelfth 

 setigerous segments) ; Vejdovsky suggests that these glands 

 are probably ovaries and testes, and I am in a position to 

 prove his supposition to be right, supposing of course that I 



