200 Memoirs of the Indian Museum. [Vol.. I, 



The first sign of sexual organs is the appearance of an apparently homogeneous 

 hyahne mass, presumably the testis, in the fifth segment, close to septum 4/5 

 Next (fig. 16) there is seen at the sides of the hinder end of the pharynx a sac 

 containing mulberry-shaped masses of sperm-mother-cells, dull and hyaline in 

 appearance ; among the morulse are large numbers of round cells, with many bright 

 granules in their interior, similar to the lymph-corpuscles of the body-cavity. 

 In the specimen shown in the figure (16), there is a similar sac (or probably an 

 extension of the former one) on the right side of the sixth segment. 



In a subsequent stage (fig. 17) the spermathecae form as sausage-shaped 

 structures, hollow, with cellular walls and with external openings at the anterior 

 part of the fifth segment. The vesicula seminalis in the same segment contains 

 developing spermatozoa, as does that in the sixth; another seminal vesicle has 

 developed, perhaps as an outgrowth of that in the sixth segment, and this extends 

 back through the seventh, eighth and ninth segments, containing developing sperma- 

 tozoa. At the hinder end of the ninth segment was seen a mass of ova; the 

 ovaries must therefore have developed. 



In fig. 18 the seminal vesicles are smaller ; but the ova are more numerous, and 

 a large mass in the s'xth segment probab y represents the ovary; the eggs seem to 

 develop in the body-cavity ; thus there are masses of them in the fifth segment, and 

 again a small mass in the ninth, at the hinder end of the seminal vesicle ; it is quite 

 possible, however, that the masses in the fifth segment are sperm-morulse. In the 

 seventh segment is seen the earliest stage of what later becomes a very prominent 

 structure ; there are seen three small masses, opaque, and composed of a number of 

 small glancing or refractile particles aggregated together. At or about this stage the 

 seminal vesicles may attain an enormous dilatation, as shown in plate xvii, fig. 19, for 

 the posterior vesicle; the anterior, however, was not obvious. Genital products (either 

 egg masses or sperm-morulae) are sometimes visible free in the body-cavity as far 

 forward as the third segment, or even occasionall}^ in the second {v. fig. 20) ; and 

 slight and unintentional violence may cause spermatozoa to burst through the body- 

 wall and be discharged from the tip of the prostomium. 



The clitellum forms as a wrinkling and thickening of the epidermis at the region 

 of septum 6-7 (fig. 20). lyater it extends over both fifth and sixth segments; the skin 

 is finely tuberculated throughout this region ,which is sharply defined both in front 

 and behind. The thickening and tuberculation are accompanied by considerable 

 opacity, so that it is impossible to make out the internal anatomy of this part after 

 the establishment of. the clitellum. 



The opaque granular mass or masses referred to above increase in size; if 

 multiple at first, they appear to unite into a single mass. This mass has apparently 

 no definitely fixed position ; though it was first seen forming in the seventh segment, 

 in another case it was found, while still of small size, to be present in the ninth. 

 I^ater, however (fig. 21), it grows to such an extent as to occupy the seventh, e'ghth 

 and ninth segments. It can then be easily seen with the naked eye in a living free- 

 moving worm as a bright white particle, the size of a small pin's head. On slight 



