492 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



groove the horns of which pass mesially just beyond the butterfly 

 marking. Just lateral to the groove is a tiny rudiment of the cres- 

 centic lip of the adult invagination. 



Just behind each spermathecal pore there is usually a genital mark- 

 ing. This marking may be transversely oval or crescentic and with 

 tlie concave margin in contact with or near to the posterior margin 

 of the spermathecal pore tubercle. The crescentic markings may be 

 quite protuberant and constricted slightly so as to produce a stalked 

 appearance. In place of or in addition to the markings just men- 

 tioned there may be small circular genital markings, each of which 

 as well as the previous markings has a grayish, translucent, central 

 portion and an opaque rim. The extra markings may be on the 

 anteriormost margins or vii-ix, the posteriormost margins of vi-viii 

 (rarely) or nearer to the setae than to intersegmental furrows; 

 one marking just in front of a spermathecal pore or just median 

 to a spermathecal pore or 2-5 intersetal intervals median to a 

 spermathecal pore. Preclitellar genital markings are lacking on 

 specimens D. 



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

 lacking ; some or all of septa 10/11-13/14 thickly muscular. 



On the esophagus just behind the gizzard there is visible in many 

 of the specimens a slight glandular collar. The intestine begins in 

 XV (15 specimens) ; in one specimen the gut slender through seg- 

 ments xv-xvii, widening gradually in xviii-xx. The intestinal caeca 

 are simple; the ventral margins incise-d, the depth of the incisions 

 variable, usually deeper posteriorly and less readily visible or lacking 

 anteriorly. 



A pair of commissures belonging to ix is present in three spec- 

 imens, in two of which one commissure is quite definitely smaller 

 than the other; a single commissure on the left side of ix (6 speci- 

 mens), on the right side (4 specimens). The last pair of hearts is 

 in xiii (16 specimens). The hearts of x are fairly large but are 

 more or less clos?ly bound to the anterior face of 10/11. All hearts 

 of ix-xiii pass into the ventral vessel. 



The testis sacs of x and xi are unpaired and ventral ; the anterior 

 sac with a bilobed ventral margin. The seminal vesicles are fairly 

 large, filling segments xi and xii and in contact transversely above 

 the dorsal blood vessel. Usually each vesicle is provided with a 

 j>rimarv ampulhi, the base of which may be more or less deeply sunk 

 into the dorsal margin of the ventral lamina. In some of the speci- 

 mens there are paired, stalked pseudovesicles in xiii. The prostates 

 extend through some or all of segments xvi-xx. The prostatic ducts 

 are 6-20 mm long, bent into hairpin-shaped loops, the ectal limb of 

 each loop much thicker than the ental limb. 



