GROWTH OF EGGS AND EGGS-STRINGS IN NEPHELIS. 193 



secretion unites the spermatozoa into spermatophores. The 

 common cavity in the main portion of the ejaculatory organ 

 opens below into a short flask-shaped canal, the neck of which 

 terminates in the male orifice, as seen in my sections. 



I have not made a thorough study of the development of 

 the spermatozoa, but, from what I have seen, it corresponds 

 very closely with wdiat Bloomfield (No. 5, p. 83) has observed 

 in Lumbricus. 



The female organ. — All of the essential anatomical features 

 of this organ are well known, but the same cannot be said 

 of its finer histological structure. The chief object in this 

 portion of my study has been to determine the place and 

 manner of origin of the egg strings, and in doing this I have 

 found it necessary to make a thorough study of the wall of 

 the ovaries at different seasons. 



Before giving the results of my histological observations 

 a brief anatomical description will be in place. 



The external orifice {f. o.,fig. 1, PI. XVI) leads into a short 

 vaginal duct (ca. 4 mm. in length), which takes a vertical 

 direction, and passes, at its upper end, into the two ovarial 

 sacs (oy.). These sacs are in free communication with 

 each other at their point of junction with the vagina, so 

 that the contents of one may be easily forced into the 

 Other. 



The ovarial tubes take at first opposite directions, nearly 

 at right angles to the longitudinal axis of the body, but, 

 soon bending backward, pursue nearly parallel courses 

 through about two segments, beneath the edges of the lower 

 oesophageal fold, and just above the vasa deferentia. Then 

 gradually approaching each other they take a median posi- 

 tion, and for the remainder of their backward course lie in 

 close contact. They extend back to the 55th — 63rd 

 ring (one, either right or left, always extending farther 

 than the other), where each, having attained a maximum 

 diameter, makes a close bend upon itself, thus forming a 

 pair of loops. 



From the posterior end of each loop the ovarial tube 

 retraces its course, following closely the path already 

 marked out. Several twists are to be seen in the posterior 

 two thirds of each loop, but in the anterior third the course 

 is more direct. At about the level of the vaginal orifice the 

 terminal portion of each tube assumes a dorsal position, 

 above the oesophagus, where, dwindling to a mere point, it 

 is lost in other tissues. The dorsal termination {t. ov.) may 

 easily be seen after peeling off the dorsal wall of the body. 

 According to Moquin-Tandon (No. 6, pi. iv) these terminal 



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