23 



posteriorly. Anterior lip with the terminal edge finely denticulate. Mandibles 

 with the palp quite rudimentary, being reduced to a small knob-like process 

 carrying 2 or 3 ciliated setae. Maxillae with the palp likewise imperfectly devel- 

 oped and without any distinctly-defined outer appendages. Maxillipeds built on 

 the same type as in the Cyclopinidce, but of comparatively simpler structure. 

 Natatory legs, as a rule, well developed, with subequal triarticulate rami, though 

 in some instances the number of joints in the rami may be reduced. Last pair 

 of legs generally small and of the same appearance in the two sexes. 



Remarks. This family, in the restriction here adopted, is chietiy distin- 

 guished from the 2 preceding ones by the rudimentary condition of both the 

 mandibular and the maxillary palps. This character is invariably found in all 

 the forms, and must be regarded as of fundamental significance. In other respects 

 this family exhibits a close resemblance to the Cyclopinidce. 



Only a limited number of species, belonging to 2 genera, are strictly 

 marine, whereas in fresh water we find a great number of forms, all generally 

 referred to a single genus, viz., Cyclops. I have, however, found it appropriate 

 to divide this extensive genus into a number of closely-allied genera (or sub- 

 genera), which will be characterised in the next parts of the present Volume. 



Gen. 10. Euryte, Philippi, 1843. 



Syn : Thorellia, Boeck. 



Generic Characters. Body, as a rule, rather robust, the anterior division 

 being considerably tumefied, and sharply marked off from the slender and attenuated 

 tail. Anterior antennas in female divided into a great number of short, but well- 

 defined joints; those in male much more strongly built, and hinged in the usual 

 manner. Posterior antennse rather stout, 4-articulate, with the last 2 joints 

 comparatively short. Mandibles with the cutting edge divided into several sharp 

 claw-like teeth, setse on the rudimentary palp not much elongated. Maxilla? with 

 the masticatory lobe well developed and armed with strong dentiform spines, 

 palp forming an oblong lamella projecting beyond the masticatory lobe and 

 terminating in a serrated edge, being moreover provided on each side with 2 

 juxtaposed setaa. Anterior maxillipeds rather stout, with the digitiform lobe, 

 issuing from the end of the 1st basal joint anteriorly, comparatively strong and, 

 like the 2nd basal joint, projecting in a claw-like spine accompanied by a much 



