14 



Recordx of flip Indian Mvsei/vi. [Vol. XIV, 



suddenly become swollen where it passes into the ectal portion of the 

 atrium, — the enlaigement is gradual. The atrium extends as far as, and 

 may extend further back in segment xii than the paratrium ; both 

 atrium and paratrium may be confined to segment xi. The portion of 

 the vas deferens which is contained within the atrial wall is considerably 

 greater than is shown in either of Michaelsen's figures (see the dotted 

 line in fig. 1), and indeed the length of the ental portion of the atrium 

 as a whole is here much greater, and its course more winding ; it is 

 here a much more conspicuous feature of the anatomy than the para- 

 trium, though the reverse would seem, from the figures, to have been 

 the case in Michaelsen's specimens. The lower (ectal) portion of the 

 paratrium, of considerable length, has here a well-marked lumen and is 

 lined by cubical cells ; it has here escaped from the voluminous peri- 

 toneal investment. Michaelsen seems to be right in denying a muscular 

 coat to the paratrium, at any rate to that part which is enclosed in the 

 thick covering of peritoneal cells. Fig. 1 gives a diagrammatic repre- 

 sentation of the male apparatus in the present specimens. 



The penis, where it occurs, appears as a pear-shaped or cylindrical 

 projection, sometimes twisted, from the male orifice. It is an evagi- 

 nation of the ectal portion of the atrium ; and it is here that the dis- 

 tinction of the ectal portion into two sections, an upper and a lower, 

 is of use ; the lower part forms, when protruded, the outer wall of the 

 penis, and the upper the axial canal which traverses the projection (text- 

 figs. 2 and 3) ; the aperture of the protruded penis is thus the junction 



Fig. 2. — Branchiura sovierhyi ; penis not pi'otruded. 

 )j 3. — „ „ penis protruded. 



a, h, c, corresj^onding points. 



between the upper and lower sections. This is borne out by the charac- 

 ters of the epithehum ; the central tube is lined by cells of a cubical 

 shape with a more lightly staining inner portion ; but it is not fo easy 

 to recognize in the outer covering of the penial projection the characters 

 of the cells lining the lower part of the atrium, since these are for the 

 most part much flattened in their new situation. 



^ATien the penis is protruded the coelomic sac extends to only about 

 kalf the height of the segment, and contains only the winding portions 



