94 ANNALS OF SCOTTISH NATURAL HISTORY 



sont presque pointus des deux bouts. lis sont attaches, par 

 leur extremite superieure et par un pedicule, au bord inferieur 

 du dernier anneau thoracique, et leur longueur egale celle de 

 l'abdomen." There also appear to be important differences 

 in the structure of the mouth appendages and swimming-feet 

 in both sexes. Sunaristes is also much longer than our species, 

 being " 5 millimetres de long " (? including tail setae). The 

 habitat is quite different, for the Sunaristes " sont les com- 

 pagnons intimes des Pagures, et c'est avec la plus grande 

 peine qu'on peut les en separer, non qu'ils soient fixes sur eux 

 comme le sont leurs parasites, mais par leur adresse a se 

 cacher dans l'interieur, ou en dessous des coquilles que ceux- 

 ci habitent." 



In 1884 Dr. Wilh. Miiller described 1 a large Copepod 

 {Longipedina paguri) that he had discovered living with 

 Pagurus bemhardus. This is considered by Dr. Canu to be 

 the same as the Sunaristes of M. Hesse ; it also resembles, 

 even more closely than Sunaristes, the form now described 

 by us. 



After a careful study of the descriptions and figures of 

 Sunaristes and Longipedina we find that, if both authors are 

 correct, the difference in their descriptions and figures are 

 scarcely reconcilable, and appear to refer to different species ; 

 and further, the difference both in respect of structure and 

 habitat between both of these and the species described by 

 us is apparently so considerable that we prefer for the present 

 to consider the Forth species as distinct from both. Canuella 

 perplexa is, so far as we know, a free-living Copepod, and is not 

 associated in any way whatever, as commensal or parasite, with 

 any other animal. 



Explanation of Plate. 

 Canuella perplexa, gen. et sp. n. 



1 " Archiv fiir Naturgesch." Jahrgang 50, Erste Band, p. 19, Plate III. 



