442 PROCEEDINGvS OF THE NATIONAL MUSEUM vol.85 



rounded end and ornamented with short transverse rows of very 

 fine teeth. 



The tips of about a quarter of the setae examined are very 

 shortly bifid. On all except one of tlie fully clitellate specimens 

 there is, on each side, a short gap in the setal circle just median to 

 the aperture of the invagination. The setae within the invagina- 

 tion are thus slightly isolated from the other male setae. Just lat- 

 eral to the lobulated ridge and in the dorsalmost portion of the in- 

 vagination is a single, bluntly rounded, rather mammalike smooth 

 and glistening tubercle. On the ventral face of the tubercle is the 

 minute male pore. In one of the Hamburg specimens each male 

 pore is on a transversely oval, flat area. There are no definite gen- 

 ital markings or papillae within the invagination aside from the 

 male pore tubercle. The lobulations of the median ridge some- 

 times look much like genital markings or tubercles, esi)ecially in one 

 worm where one of the lobulations in each invagination has been 

 crow^ded anteriorly into a position just in front of the main portion 

 of the ridge. No pores have been found on these lobulations or 

 demarcation into rims and central areas as on genital markings 

 associated with glands. 



The only genital markings are tiny circular tubercles in close 

 proximity to the spermathecal apertures, usually but one of these 

 markings associated with each aperture, rarely two. The marking 

 is on the anteriormost margin of the segment just at or actually 

 within the secondary spermathecal aperture. The marking some- 

 times appears to be just median to the aperture. Perhaps a more 

 complete retraction of the spermathecal chamber would result in 

 retracting the marking into the parietes. When two markings are 

 visible in connection with any spermathecal pore, one is always 

 within the aj>erture. In one specimen the markhig in connection 

 with each spermathecal aperture is on the posteriormost margin of 

 the segment and immediately in front of the aperture. 



Internal anatomy. — Septa 5/6-7/8 are thickly muscular; 8/9-9/10 

 lacking; 10/11-12/13 thickly muscular; 13/14 muscular; 14/15 slightly 

 muscular. 



The intestine begins in xv (18 specimens). The intestinal caeca 

 are simple but the ventral margins, especially posteriorly, are slightly 

 incised in such a way as to produce an appearance of a row of 

 very short but definite lobulations. There is a small, whitish, occa- 

 sionally lobed, glandular collar on the esophagus just behind the 

 gizzard. 



The single heart of ix is on the right side in 8 specimens, on the 

 left side in 6 specimens. The hearts of x are present in all speci- 

 mens but are often concealed by the connective tissue that binds 



