﻿186 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loo 



first and second swimming legs, reaching the base of their coxa, and 

 (5) "posterior margin distal to the capsule with a few plumose setae." 

 The capsule apparently refers to the semen capsule on the dorsal sur- 

 face of the third leg in the male, though not shown in his figures. 



In a footnote Tokioka mentioned the fact that Dr. Wilson in a per- 

 sonal note to Professor Komai stated that he had examined some speci- 

 mens of Argulus collected from goldfish in Tokyo, which showed 

 difference in several features from Thiele's original description, and 

 expressed in this footnote the opinion that all the differences alleged 

 by Dr. Wilson were "nothing but individual or rather seasonal varia- 

 tions . . . The material of this group in my hand which have been 

 obtained from various seasons and from various localities show a fairly 

 wide range of variation in all respects he mentioned." But un- 

 fortunately, though Tokioka had at his disposal large quantities of 

 this species and made (1936b) observations on larval development 

 and metamorphosis, he gave no critical comparison or statistical 

 study of the variations in question. Had this been done, there might 

 be less confusion in the taxonomy of this species. 



In his review of the genus Argulus in the collection of the U. S. 

 National Museum, Meehean (1940) stated that specimens collected 

 by Dr. Pearse in Japan and those sent to him from that country 

 proved to be identical with A. trilineatus Wilson. Therefore, he 

 placed A. trilineatus Wilson as synonymous with A. japonicus Thiele 

 and gave a description with three drawings emphasizing the structures 

 of the chitinous ribs of the sucking cups, the respiratory areas, and 

 the male accessory organs of the legs. He pointed out both by 

 drawing and description (1) what Thiele only showed by a drawing, 

 and Tokioka omitted all together, that between the second and third 

 legs there is a slight spinous lobe on the lateral edge of the thorax 

 directed from the base of the third leg anteriorly, (2) that the basal 

 segment of both the third and the fourth appendage is only half as 

 long as that of the anterior leg, and (3) that there is a large papilla 

 at the ejaculatory duct on the end of the thorax. 



Wilson (1944) in a paper on parasitic copepods also based on ma- 

 terial in the collection of the U. S. National Museum questioned 

 Meehean's conclusions. To begin with, since "more recent specimens, 

 also including both sexes, were taken from goldfish at Tokyo and 

 sent to the National Museum" and "since they differ from Thiele's 

 in a few details" he described and figured the Tokyo specimens, giving 

 separate account for each sex, much more in detail, and hence more 

 useful for comparative purposes than all the previous authors. In 

 the case of the female he described the relative size of the thoracic 

 segments for the first time : second and third segments much wider 

 than long, fourth narrowest with a constriction at the center of each 



