266 Lernaeopoda 
represents my view of the mutual relationship existing between these four 
species: 
L. mustelicola 
L. globosa 
/ 
Lernaeopoda ancestor 
Note on the Males. 
Dr Charles Branch Wilson has kindly sent me a communication calling 
attention to the relative position of the second maxillae and maxillipedes 
in the males of the Lernaeopodidae. On consulting Fig. 38, PI. XXXYI, of 
his paper on the development of Acktheres ambloplitis (Proc . U. S. Nat. Mus. 
xxxix) it appears that it is the long posterior pair of appendages that corre¬ 
spond to the second maxillae in the females, and not the short anterior pair. 
In the subsequent development of the male these long maxillae remain 
posterior, while the short maxillipedes migrate forward between the bases of 
the maxillae and become anterior. Hence in the adult male the short, stocky 
anterior pair of mouth parts represent the migrated maxillipedes, and the 
longer and slenderer posterior pair represent the second maxillae which have 
remained where they were first formed. This, he shows us, is most clearly 
observed in the larval history, and if true of AchtJieres it follows from analogy 
that it is probably true of the other genera including Clavella. 
(My best thanks are due to Miss E. C. Humphreys for her kind assistance 
with the figures.) 
Erratum. 
Parasitology, xi, 120, five lines from the bottom of the page: 
For “first maxillae” read “second maxillae.” 
