TKEMATODE PARASITES. 105 



whole body, gives to the species a characteristic appearance, different from that of the 

 other Anaporrhutinse. 



Excretory vesicle Y-shaped, with long median trunk, dividing a little behind the 

 level of the posterior end of the yolk glands, and with shorter paired branches not 

 crossing the intestinal cceca, but ending at the sides of the posterior edge of the ventral 

 sucker. 



Genital openings ventral from pharynx, somewhat at the right of the median line. 

 Cirrus-pouch wanting. 



Testes outside the intestinal coeca, but still within a distance of almost 2 millims. 

 from the lateral margins of the body, extending from 0'5 millim. behind the posterior 

 margin of the ventral sucker to l'S millim. behind the same. Their number is 14 at 

 the right side of the body and 17 at the left side, pressed closely together in two rows 

 which unite behind ; the inner edge of these rows has but about half the length of 

 the outer. Each testis is mulberry-shaped. The vasa efferentia from the single testes 

 arise between the two rows and unite soon to form the vas deferens of each side. 

 The two vasa deferentia do not anastomose with each other, as they are said to do 

 in A. albidum, but only unite at about the level of the division of the intestinal cceca 

 to form a very convoluted vesicula seminalis. 



Ovary globular, with a diameter of - 4 millim. It is situated just behind the ventral 

 sucker, at the right side of the body. Receptaculum seminis of about the same size, 

 situated at the side of the ovary in the median line. Yolk glands between the 

 intestinal cceca and the paired branches of the excretory vesicle, the left just behind 

 the ovary, and the right symmetrically on the other side of the body, each of them 

 consisting of several tubules, which do not anastomose with each other, as they are 

 said to do in Anaporrhutum albidum, Ofenh., and Probolitrema capense, Looss.* 



Uterus similar to that of Probolitrema ricliiardi (Lop.) Lss., but ending about 

 - 7 millim. in front of the blind end of the intestinal cceca, and passing at the right 

 side of the ventral sucker. 



The new species Anaporrhutum largum differs from both Anaporrhutum albidum, 

 Ofenh., and the two species of the genus Probolitrema, Lss. (P. richiardi and 

 P. capense), in several points of its anatomy, especially in the position of the testes 

 and the yolk glands, to which Looss has ascribed generic value. Accepting 

 Probolitrema as a separate genus, it woidd be necessary therefore to create a third 

 genus for the new species. But doubtless all these Anaporrhutinae living in the body 

 cavity of Selachians are more closely related to each other than to Plesioehorus 

 cymbiformis (Rud.). placed by Looss in the same sub-family. It seems to me, there- 

 fore, that Probolitrema is to be regarded only as a sub-genus of Anaporrhutum, or 



* In addition to Anaporrhutum largum I have also examined a species of Probolitrema very similar to 

 P. richiardi (Lopez), if not identical with this, which is found in an undetermined shark from the Ulle Sea 

 (Dutch India), and belongs to the Natural History Museum of Hamburg (No. 17705). In this species also 

 the tubules of the yolk glands do not anastomose with each other. 



P 



