TREMATODES FROM FISHES — ^LINTON 45 



Subfamily ZOOGONINAE Odhner, 1902 

 Genus ZOOGONOIDES Odhner, 1902 



ZOOGONOIDES LAEVIS, new species 



Plate 21, Figures 275-277 



Small distomes found on different occasions in the intestine of the 

 tautog were at first thought to belong to the species Z. viviparus 

 (Olsson) from Pleuronectes microcephaliLS^ and reported by Odhner 

 and Nicoll from a number of hosts mainly belonging to the Pleuro- 

 nectidae. 



The principal points of difference between these distomes from 

 the tautog and Z. viviparus are the comparative absence of spines, an 

 unimportant feature, and the greater length of the intestinal rami. 

 There is a difference, also, in the position of the genital pore from 

 that assigned to it by some authors. In this, however, there is some 

 disagreement. Thus, Olsson 's figure of his Distoma vivipara ^ places 

 the genital pore near the right side of the neck. Odhner ^ describes 

 and figures Zoogonoides vivipar'us (Olsson) as having the genital 

 pore near the left margin at the level of the forking of the intestine. 

 Nicoll ^^ gives its position as near the left margin somewhat back of 

 the forking of the intestine. Fuhrmann ^^ describes and figures the 

 genital pore on the left side. In his characterization of the Zoogon- 

 idae he states that the genital pore is not far from the left border 

 of the body. 



While the resemblance of these distomes to Z. viviparus is close, 

 they differ consistently in the length of the intestines, which extend 

 beyond the ventral sucker about to the level of the seminal receptacle. 

 Also, they appear to be practically devoid of spines. I do not find 

 any mention of spines in my notes made on fresh material, or on 

 formalin material collected by Mr. Edwards. Careful search on 50 or 

 more specimens mounted in balsam resulted in the finding of two 

 in which a few exceedingly minute spines were faintly visible at the 

 extreme anterior end dorsal to the oral sucker. 



These distomes are small, fusiform, and smooth, or with but few 

 minute spines; yellowish, tinged with red; ventral sucker much 

 larger than oral, near the middle or a little in front of the middle, 

 its aperture transverse. Average of 10 specimens in balsam : Trans- 

 verse diameter of oral sucker 0.14 mm., of ventral sucker 0.24 mm. 

 There is no prepharynx; pharynx small, broader than long; esopha- 

 gus short ; intestinal rami extend back of the ventral sucker, approx- 



sLunds Univ. >.rs-skrift, vol. 4, pt. 2. No. 8, pp. 28, 29, pi. 4, fig. 73, 1867-68. 



» Centralbl. Bakt. und Parasit., vol. 31, pp. 62, 63, fig. 2, 1902. 



1" Ann. Mag. Nat. Hist., ser. 7, vol. 19, pp. 83, 84, flgs. 8, 9, 1907. 



« Kiikenthal and Krumback's Handbuch der Zoologie, vol. 2, p. 103, fig. 122, 1928. 



