EARLY DEVELOPMENT OF GRAFFILI.A. 1 77 



of the median line somewhat below the central axis of the animal 

 Fig i 2) two very delicate, short sperm ducts which place 

 i In- gonads in communication with the seminal vesicle; (3) a 

 seminal vesicle, which is a rather large pear-shaped sac situated 

 just In-low the genital pore; and finally, a plug-like peni> arising 

 troin tin- pointed, ventrally directed end of the seminal vesicle. 

 In OIK- ot the clearest specimens secured earli -perm duct i- -mi 

 to ari-i- troin the posterior median corner of the te-ti- ,m<l to pass 

 inuard to the anterior face of the seminal vesicle, inn tin- the 

 latii-r .it .ilioiit the di\'iding line between it- upper, bullion- 

 |iortioii and the smaller lower part. The peni- \\lu-n contracted 

 i- c\ti mel\ difficult to make out, and since in mounted prepa- 

 ration-, thi- condition is almost invariably met with, not m.my of 

 tin- ili i, til- o| the- organ were studied. The penis \\ln-n extended 

 ol course |irotrudes into the common atrium, \\hich in turn 

 communicates with the exterior by means of the small genital 



1 1 he pore lies in the median ventral line at a point -i main I 



ibont one third the distance from the anterior end of tin- l>od\. 



In large individuals the testes are seldom found, ami \\hrn 

 |irr-fin .in- mi i e degenerating fragments. Tin- seminal \e-icle, 

 ho\\e\er. p.i-i-t- .it least until a late period of tin \ n i-t -naial 

 life, but iii many animals becomes reduced in si/e. The penis 

 also degi derates sooner or later. During this perio<l of degen- 

 eration o| the male organs the female reprodin ti\ i -titntnie- 

 gtadualK make their appearance. One occasionally meet- \\ith 

 specimen- in which the transition from tin "male" to the 

 "female" -tate is seen, and from such individuals nio-t of the 

 important ]n.ints concerning the female organs can be made out. 



In the t\ pical " female" condition the seminal \e-i< le i- alua\ - 

 pn-i nt. though as stated above it mn\ become greatly n-din ed 

 in >i/e, and the atrium with its genital pore still per-i-t-. Ju>t 

 back of the -eminal \~esicle and (loyally the atrium gives ri-e 

 to a small di\ erticiilum, which both from it- po-iti<,n and char- 

 acter -ugge-t- its homology with the receptaculum >emini> of 

 the other members of this genus, although in the two clearest 

 cases coming under the observations of the writer tin- \e~icle 

 contained no spermatozoa (Fig. 2). If this interpretation is 

 correct then the receptaculum seinini- i- in this species clearly a 

 degenerate -tructure. 



