26 EDWIN LINTON. 



6. A momentary pause marks the arrival of the sperm at the 

 ootype. 



7. Powerful contractions of the walls of the ootype eject the 

 egg from the uterus into the water. 



Emendation of the Description of the Species. 



In the original description of this species mention was made 



■of but two pairs of hooks on the sucker. A third pair of minute 



Jiooks, posterior to the others, was subsequently found (Fig. i). 



Washington and Jefferson College, 

 Washington, Pa. 



Explanation of Abbreviations. 

 Meaning of letters which are used in more than one figure. 



h. Yolk duct leading from yolk reservoir to the common duct. 



c. Germ duct leading from the germarium to the common duct. 

 rd. Common duct leading from the junction of b and c to ootype. 

 cp. Cirrus-pouch. 

 em. Ootype. 



f. Beginning of germ duct in germarium. 



0. Germarium. 

 od. Oviduct leading from ootype to exterior. 



/. Cirrus. 



sd. Seminal duct leading from seminal receptacle to common duct. 

 sd^. Point where sd enters the common duel. 

 sp. Spermatozoa in seminal receptacle. 

 sv. Pulsating organ at base of cirrus-pouch. 



/. Testes. 

 ■vd. Vas deferens. 

 vg. Vitelline gland. 



yd. Yolk duct leading from vitellaria to yolk reservoir. 

 yr. Yolk reservoir. 



