432 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



The genital markings are two pairs on xvii and xix, each marking 

 having a thick opaque rim and a grayish, concave, circular, central 

 portion. The markings appear to be postsetal in position, but the 

 setae are lacking on both xvii and xix immediately in front of the 

 markings. Each marking is about 6 intersetal intervals wide trans- 

 versely and is separated from the marking of the opposite side by a 

 midventral space about equal to 13-15 intersetal intervals. 



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

 resented only by a thin ventral rudiment; 9/10 lacking; 10/11-12/13 

 membranous but slightly strengthened. 



The intestine begins in xv. The intestinal caeca are simple with 

 smooth margins, short, extending through 2-3 segments. 



There is a pair of hearts belonging to ix. The last pair of hearts 

 is in xiii. 



There is a pair of testis sacs on the anterior face of 10/11; no 

 transverse connection between the sacs noted. The testis sac or 

 sacs of xi extend dorsally at the sides of the esophagus to the dorsal 

 blood vessel and contain the hearts of xi as well as the seminal 

 vesicles of that segment. The seminal vesicles, paired in xi and xii, 

 are small vertical bodies. Prostates are entirely lacking in one speci- 

 men, extending through xvii-xx in the other. In the first specimen 

 the prostatic duct is represented only by a short, soft, whitish widen- 

 ing of the vas deferens just as it passes into the parietes. In the 

 other specimen the prostatic ducts are short and soft, bent into a 

 sort of C-shape but with a tiny quirk in the duct at each end of the C. 



The spermathecae of both specimens are probably abnormal: the 

 duct-ampulla portion of the apparatus appears to be very rudi- 

 mentary, while the diverticular portion seems, relatively, to be hyper- 

 trophied. The diverticulum passes into the median face of the 

 duct-ampulla rudiment. 



There is glandular material in the parietes dorsal to each genital 

 marking, the material projecting slightly into the coelomic cavity. 



Remarks. — The types are almost certainly abnormal (spermathecae 

 in both specimens and prostates in one specimen). Examination of 

 normal specimens may enable recognition of further abnormalities 

 in the types. 



At present P. exilis can be distinguished from other quadrithecal 

 Chinese species of Pheretima with spermathecal pores on 5/6-6/7 

 by the inclusion of the seminal vesicles of xi witliin the posterior 

 testis sacs. 



