616 



to emphasize this incompleteness more fully. Giesb recht himself in 

 his latest word on the subject, "Die Asterocheriden des Golfes von 

 Neapel" (Fauna and Flora, Gulf of Naples, Monograph 25, 1899), enu- 

 merates fifteen families which he says "can be assigned with certainty" 

 to the Podoplea (p. 57), three of them being fish parasites But he 

 makes no attempt to even mention the doubtful families, and hence we 

 cannot judge how many of these there are in his estimation. 



Smith, on the other hand, comes out boldly and places all of the 

 parasites and semi-parasites under the Podoplea, but acknowledges that 

 the position of some of them is doubtful. He enumerates in all twenty- 

 four families, four in the Gymnoplea and twenty in the Podoplea. After 

 finishing his remarks on the seventh family, he says "The rest (namely, 

 the other seventeen families) are either true parasites or else spend a 

 part of their lives as such" (p. 6.3). Of these only half can be definitely 

 located, leaving seven families or 30 % of the whole group still in doubt. 



Caiman is more conservative; after locating twenty-one families 

 more or less definitely, he adds "The position of the remaining families 

 (consisting wholly of parasitic forms) with respect to this system of 

 classification is not yet determined" (p. 103). 



He mentions six of the "most usually accepted" of these "remaining 

 families" but omits the Antheacheridae (Philichthyidae) which is fully as 

 well known as any of the others, and which is included by Smith. This 

 makes seven families undetermined and twenty-one determined or 

 exactly 2h% and lh% respectively. 



But even these figures do not give us a correct idea, for the great 

 majority of the determined families contain but a few genera, while these 

 undetermined ones are among the latest in the group and together 

 contain more than two-fifths of all the Copepod genera. 

 Cannot such a division be justly called incomplete? And does not the 

 failure to definitely locate from 40^ to 45^ of the group under con- 

 sideration substantiate the testimony of degeneration that the basis of 

 primary division which has been used possesses a low systematic value ? 



b. Nor is this due to a lack of definite information, we already 

 know the morphology of these "remaining families" in detail, as well 

 as the complete life history of one or two type genera in at least four 

 of them. 



And there is apparently no hope that we shall ever be able to 

 locate some of them according to this system. Giesbrecht has stated 

 in clear and unmistakable terms the diagnostic character which forms his 

 primary basis of division. The body segment carrying the fifth legs 

 belongs in the Gymnoj)lea to the fore body, its legs are normal in the 

 female, modified into copulatory organs in the male, so that in this sub- 



