[cooper] 



TREMATODES FROM MARINE FISHES 



195 



all of the largest at hand is, as indicated in the table below, noticeably 

 smaller than the oral; yet the body is "often of uniform breadth, 

 (but) narrowed in front of the ventral sucker and behind the second 

 testis" (Fig. 14). Again, since, so far as I am aware A. petalosa, the 

 original description of which was not available, has been reported from 

 Acipenser rubicundus LeS. only, while C. laureaHim has been found in 

 the Yellow Perch, one of the hosts listed above, I thought it advisable 

 to refer the material to the above species, especially too, in view of its 

 scarcity and of the added fact that no figures are given with Stafford's 

 paper while those by Linton are of evidently much contracted speci- 

 mens.* 



The following table shows the occurrence of the species and 

 measurements of the largest specimens from the ditïerent hosts : 



Eggs from another lot measured when fresh, 0-062 — 0-069X0-041 — 0-044. 



*Since the preparation of the manuscript of this paper I have obtained 

 numerous specimens of Acradaclyla petalosa (Lander) from Acipenser rubicundus 

 LeSueur, the Lake Sturgeon, from the St. Lawrence River, near Iroquois, Ontario, 

 and am able to confirm Stafford's description (704, p. 491) of the species, especially 

 in regard to the position (and size) of the genital opening and the large size of the 

 cirrus-sac. The latter characters, however, seem to be more distinctive of the genus 

 than do the arrangement and size of the oral papillae, particularly the posterolateral 

 pair, which, as also brought out by the above comparison of the two species, closely 

 resemble those of C. laureatum. A typical specimen gives the following measure- 

 ments: Length, 2 •44mm.; maximum breadth (immediately ahead of the anterior 

 testes) 0-61; length of oral sucker, 0-38, diameter, 0-33; diameter of ventral sucker, 

 0-27. 



