ART. 13 TREMATODE PARASITES OF MARINE MAMMALS PRICE 19 



ovary. The seminal vesicle is about 830/* long bj^ 290/>i wide and 

 almost fills the posterior part of the cirrus pouch; pars prostatica 

 slender, about 700/a long, and separated from the seminal vesicle by 

 a sharp constriction; ejaculatory duct relatively short. The cirrus 

 is protrusible and armed with strong spines. The spines are about 

 40/t long and are inserted into a basal disk which is about 16/i, in 

 diameter. Testes oval in shape and situated in the anterior fourth 

 of the body; the anterior testis is 900/a to 1.5 mm long by 620/* to 

 930/* wide, and the posterior 1 mm to 1.6 mm long by 620/a to 850,a 

 wide, the distance between them being 310/x to 1.2 mm. The ovary 

 is transversely oval, 232/* to 387/* long by 465/* to 590/* wide, situated 

 a short distance cephalad of the anterior testis and to the right of the 

 median line. Seminal receptacle not observed. Laurer's canal is 

 slender and sinuous, and opens in the mid-dorsal line at the level 

 of the ovary. Mehlis's gland is large and is situated median and 

 dorsal to the ovary. The vitellaria consist of chainlike rows of 

 follicles, which radiate to form rosettelike masses, and extend from 

 the anterior testis to the posterior end of the body; the masses of 

 follicles are distributed on all sides and form a continuous layer be- 

 neath the dermomuscular layer of the body. The uterus consists of 

 six or more transverse coils confined to the intercecal field between 

 Mehlis's gland and the acetabulum. The vagina is well developed, 

 unarmed, and about one-half the length of the cirrus pouch ; it opens 

 at the base of the genital sinus to the left of the male genital aper- 

 ture. The eggs are oval, 97/* long by 52/* wide, with a short prolonga- 

 tion at the posterior pole, triangular in cross section. 



Host. — White whale {Delphinapterus leucas). 



Location. — Intestine. 



Distribution. — North America (Alaska). 



Type sfecimens. — U.S.N.M. Helm. Coll. No. 30807; paratypes, 

 No. 26157. Collected by Dr. Seymour Hadwen, September 9, 1921, 

 at Golovin, Alaska. 



Remarks. — Iladicenius seyiihouri appears to be more closely related 

 to Synthesiuin tursionis than to any of the other species of Campu- 

 linae. Both are parasites of the intestinal tract of cetaceans and are 

 similar in body fonu. They differ, however, in two principal charac- 

 ters, which are considered generic, viz, the copulatory organs and 

 distribution of the vitellaria. In Iladwenius seymouri the cirrus is 

 armed but the vagina is not, and the vitelline follicles are arranged 

 in rosettelike masses similar to those in Lecithodesmus^ while in 

 Synthesiv/tn tursionis both cirrus and vagina are armed and the vitel- 

 line follicles are distributed in small grapelike groups. Other dif- 

 ferences are present, but these appear to be only of specific value. 



