PROCESS OF EGG-MAKING IN A TKEMATODE. 21 



{t), which are subglobular in shape and he near each other trans- 

 versely placed and a little in front of the middle of the body. The 

 cirrus pouch pulsated rhythmically and continued to pulsate long 

 after all movement had ceased in the other organs. 



The female genitalia are more complicated. FilHng the body 

 laterally and posteriorly are the vitellaria {vg). These are den- 

 dritic glands whose ducts ultimately are collected into a trans- 

 verse duct {yd) which enlarges into a vitelline reservoir {yr), 

 lying a little to the left and a little in advance of the germarium 

 {o). Immediately in front of the testes is the germarium [o), a 

 somewhat trilobed organ lying on the median line. A short duct 

 {c) passes at first dorsad then cephalad from the germarium 

 where it joins another short duct [o) coming from the vitelline 

 reservoir (jT ). The common duct ( r^/) then passes near the 

 median line, cephalad to the shell mold (ootype) {em), which 

 lies near the cirrus-pouch and to its left. About midway 

 between the germarium and the ootype the common duct is 

 joined by a minute duct {sd, sd'), which enters on its dorsal side 

 and comes from the seminal receptacle {sr). The seminal recep- 

 tacle lies to the left and a little in advance of the ootype. 



The cells which constitute the shell-forming gland surround 

 the common duct for some distance back of the ootype. The 

 oviduct passes forward from the ootype, lies beside the cirrus, 

 and opens with it in the genital notch which lies on the anterior 

 border on the left side of the head. The vagina opens in the 

 genital notch close to the left side of the oviduct. It leads 

 into a capacious seminal receptacle {sr), from the caudal end of 

 which the seminal duct {sd), above mentioned, proceeds mediad 

 to the common duct from the vitelline reservoir and germarium. 



Physiological Action of the Genitalia which are Con- 

 cerned IN THE Process of Egg-Making, 

 Following are the events named in order as they were seen to 

 occur in a specimen which was lying in sea water under a cover- 

 glass. First, a lobe {a) of the vitelline reservoir {yr) contracted 

 vigorously thereby emptying itself of a definite mass of the 

 coarsely granular vitelline substance with which it was filled. 

 As this takes place in a definite portion of the reservoir, it fol- 



