622 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



talis Steenstrup and Liitken, 1861; rhombi, gibbus, gracilescens Kroyer. 

 1863; obscwus Bass ett- Smith, 1896. 



The figures given by the various authors all show the same general 

 proportions, body regions, and appendages, especially the small fourth 

 legs. It is obviously impossible that there should be so many species 

 of the same genus on one fish and corresponding so closely. And 

 when we come to examine the figures and descriptions carefully we are 

 at a loss to discover anything of specific value. The differences are all 

 trivial and of no greater value than those recorded under the single 

 species Caligus rapax. 



Bassett-Smith in his description of the species which he calls obscurus 

 makes his specimens, which were all females, the same species as Baird's 

 male, which the latter described in 1850. 



This decision is based upon the bifurcation of the branches of the 

 furca. If that were correct it would come the nearest to a specific 

 difference of anything connected with the entire seven species. But 

 Bassett-Smith in his first paper (1896) calls this species {ohscurus) a 

 Lcpeophtheirus ; in another paper published the same year he labels 

 the figure he presents Caligus, and puts a pair of lunules in the frontal 

 plates; again in 1899 he goes back and calls it Lepeophtheirus. 



In the face of such vacillation too much stress can not be placed 

 upon the bifurcation of the branches of the furca, especially as this 

 one detail is all he has ever presented in the way of a description. 



Baird himself suggested in his original description that the male he 

 described as obscurus might very well be the male of the species hippo- 

 glossi, only the female of which was then known. 



If his figure be compared with that given by other authors of a 

 male hippoglossi, the resemblance will be found very close. 



Furthermore Bassett-Smith places a question mark in every instance 

 after the name of his species. Until he can give us more convincing 

 proof, therefore, and a better description of his species we are not 

 warranted in accepting its validity. 



With reference to Beneden's species it is enough to say that not 

 very much credit can be given to an author who represents the fourth 

 legs as attached to the basal apron of the third legs, while the true 

 rami of the third legs are attached to the lateral lobes of the carapace(I). 



A careful reading of Kroyer's diagnosis of the three species rhombi, 

 gibbus, and gracilescens, together with a comparison of the figures he 

 presents, will quick \y convince one that the three are identical. All 

 the details which he gives of the appendages show absolutely no differ- 

 ences, except trifling ones of size. The second antenna?, second max- 

 illae, furca, second maxillipeds, and third and fourth swimming legs 

 are identical. The proportions of the different regions are also ver}^ 

 nearly identical, only such slight differences as occur in any species. 

 His specific distinctions, so far as one can judge, rest solely upon the 



