56 PROCEEDESTGS OF THE NATIONAL MUSEUM vol. los 



of calling the posterior sac by this name as there are no testes present 

 in segment 12. He proposes terming this structiu-e a "membranous 

 sac." The testis sacs of segments 10 and 11 are very large, extending 

 laterally almost to the body wall and medially to the esophagus to 

 enclose the male organs and hearts of their corresponding segments. 

 Sections of the Pelham specimens show that the sacs are unpaired 

 and annular, as each is continuous dorsally and ventrally with its 

 member of the opposite side (fig. 2) . This is in agreement with Chen 

 (1933). Gates (1935, 1939) describes the sacs as U-shaped with no 

 dorsal connection, and it is possible that a degree of variability may 

 exist as to the shape of these structures. The membranous sac of 

 segment 12 is similar in structure to the testis sacs, but only encloses 

 the seminal vesicles of its segment. 



The vas deferens from each testis extends posteriorly to form a close 

 contact with the other spermatic duct of its side in segment 13. Al- 

 though the two ducts maintain their individuality throughout, this 

 can only be seen in sectioned material. The spermatic ducts pass 

 posteriorly, lateral to the nerve cord, until they communicate with the 

 common prostatic-spermatic ectal duct. 



The pair of prostate glands, lying in segments 17 to 19 and pene- 

 trating septa 17/18 and 18/19, are large flattened structures usually com- 

 posed of two or more irregular lobes (fig. 3). In life they are milky 

 white in color, and bulk large during sexual maturity so that they can 

 be seen as large masses through the body wall of fully clitellate speci- 

 mens. From the two major lobes ducts emerge and pass ventrally 

 to unite with the two spermatic ducts of a side in the common prostatic- 

 spermatic ectal duct. This heavy structure coils once and opens 

 through the body wall at the male pore in segment 18. Accessory 

 glands are located just anterior and posterior to the base of the above 

 duct in segments 17 and 19, opening on the external genital papillae. 



Externally the male pores open ventrally on small, raised tubercles 

 in line with the setae of segment 18 (fig. 4,a). The two pairs of 

 flattened genital papillae are situated close to the intersegmental 

 furrows 17/18 and 18/19 just medial to the male pores. In aU of the 

 specimens from Pelham and in the accounts of other authors no 

 variation in the appearance and location of the male reproductive 

 organs, with the exception of the testis sacs, has been noted, 

 f§ Female reproductive system: The ovaries are situated on the 

 posterior face of septum 12/13 just lateral to the ventral nerve cord. 

 They are white in color and are composed of a large number of digital 

 processes arranged so as to resemble a fan. The paired oviducal 

 funnels are large, convoluted structures in segment 13 facing the 

 ovaries and communicating posteriorly with the short oviducts that 

 pass through the body wall in segment 14 to the single female pore 



