416 PROCEEDINGS OF THE NATIONAL MUSEUM vol.85 



are deep but confined to the parietes. The lateral wall of the invagi- 

 nation is thin, the ventral margin of the lateral wall liplike. On the 

 median wall of the invagination is a large, circular, smooth, glistening 

 area. The central portion of this area may be depressed into a ver- 

 tical slit or groove. In the lateralmost or dorsalmost portion of this 

 groove or slit the tip of the penis can usually be seen. The slit opens 

 into a small, rounded, muscular bulb into which the penis is re- 

 tracted, partially or completely. The smooth area on the median 

 wall of the invagination may be raised in such a way as to have the 

 appearance of a thickish ring around the base of the penis. 



The everted parietal invagination has the appearance of a spher- 

 oidal knob. On the ventral face of this knob, in incomplete eversion, 

 is a pitlike depression from which the tip of the penis protrudes. In 

 complete eversion the entire length of the penis is visible. The penis 

 is slenderly tubular, the tip rather pointed, the base slightly thicker ; 

 about 1 mm or slightly more in length. 



The genital markings are presetal, paired, on xviii and xix. Each 

 marking is transversely but shortly elliptical, about 5-9 intersetal 

 intervals wide transversely, with a large, grayish, translucent, con- 

 cave-depressed center and an opaque whitish rim. The lateral mar- 

 gins of the markings are just median to the apertures of the parietal 

 invaginations, the median margins of a pair separated by a mid- 

 ventral space equal to 5-6 intersetal intervals. Anteroposteriorly the 

 markings extend from just in front of the setae to the interseg- 

 mental furrow. The latter is slightly displaced toward the anterior 

 end by the genital markings on all specimens on which the furrow 

 is visible. 



On each side of the body and extending from the margin of the 

 clitellum posteriorly for several segments is a rather high ridge. 

 The midventral region between these two ridges has a longitudinally 

 rectangular appearance. The apertures of the male parietal invagi- 

 nations are on the ventral faces of the longitudinal ridges, the genital 

 markings on the median faces. 



Internal anatomy. — Septa 5/6-9/10 are thicldy muscular; septa 

 10/11-12/13 also muscular, especially 10/11, but not so thick as the 

 anterior septa. 



The esophagus in segments xiii or xiv-xv is strongly distended by 

 soil, the esophageal wall very thin, sometimes actually transparent. 

 The origin of the intestine is not quite clear but appears to be in 

 xvi. The intestinal caeca are simple, long, slender, with smooth 

 margins. 



The paired hearts of ix-xiii all pass into the ventral trunk. In 

 two specimens a pair of large heartlike commissures in ix connects 



