141 



the sea, often jumping out of the water; and, as it generally occurs in great 

 abundance, the presence of this Calanoid in calm weather may be easily observed 

 by a slight disturbance of the surface, as if by fine rain. The movements of 

 this Calanoid are exceedingly rapid and energetic, and indeed, when kept alive 

 in a bottle with sea-water, it is a matter of great difficulty to catch the specimens 

 with the ordinary implements, viz.. a small feather or a dipping-tube. When 

 brought under the microscope in a small quantity of water, the animal immediately 

 jumps off the object-glass, and in order to prevent its escape, it is therefore 

 necessary to add to the water a little alcohol or other narcotizing fluid. 



Distribution. British Isles (Brady), coast of France (Canu), Mediter- 

 ranean (Glaus), Atlantic Ocean, between Lat. 36 and 67 N. (Giesbrecht), Black 

 Sea (Karawajew). 



Gen. 27. LabldOCera, Lubbock, 1853. 



Syn: Pontella, Dana (part.). 

 Hemipontetta, Glaus. 



Generic Cht(r<t<-lcrx. Body less slender than in Anomalocera, with the 

 anterior division more tumefied. Cephalosome with or without lateral hooks, 

 rostrum about as in Anomalocera, but somewhat smaller. Last segment of meta- 

 some confluent with the preceding one, lateral lobes more or less produced behind. 

 Urosome in female comparatively short and composed of 2 or 3 segments, that 

 in male 5-articulate, genital segment in female generally asymmetrical. Caudal 

 rami of moderate size, sometimes conspicuously unequal in female. Ventral eye 

 of same appearance in the 2 sexes, dorsal eyes each with a single cuticular lense, 

 rather small in female, greatly developed in male. Anterior antennae slender and 

 elongated, consisting in female of 23 articulations ; right antenna in male with 

 the middle section moderately tumefied. Posterior antennae with the inner ramus 

 confluent with the basal part, outer ramus larger than in Anomalocera. Oral 

 parts on the whole resembling in structure those in that genus. Inner ramus in 

 all the natatory legs biarticulate. Last pair of legs in female with both rami 

 uniarticulate and less unequal than in Anomalocera: left leg in male sometimes 

 with a rudimentary inner ramus, right leg terminating in a very large and 

 perfect chela. 



Remarks. This genus, established by Lubbock, is chiefly distinguished 

 from Anomalocera by the presence of only a single pair of dorsal ocular lenses, 



