12 BRITISH COPEPODA. 



the palp is atropliied, and is represented only 

 by two or three ciliated setae. In the Gonjcceidce 

 the mandible is small and weak, its palp obsolete 

 or reduced to very small dimensions, while in some 

 8i])honostoma^ the mandible itself is converted into 

 a long and slender piercing style, which is enclosed 

 in a tube resembling considerably the antlia of Lepi- 

 dopterous insects, and composed of prolongations 

 of the upper and lower lip (Plate XCIII, fig. 3); 

 in Cyclopicera, however (a genus here included 

 amongst Siphonostoma), there is an intermediate 

 condition of things ; the mandible is very much elon- 

 gated, slender, and finely toothed at the apex, being, 

 in fact, almost stylet-shaped, but not enclosed in any 

 sheath; the palp, also, is quite rudimentary (Plate 

 LXXXIX, fig. 4). 



The maxillce are small appendages, composed of a 

 chewing portion, which is divided at the apex into 

 numerous rather long and slender curved teeth, and 

 of a complex, lobed, and setiferous palp, which 

 frequently has filamentous appendages, possibly of a 

 branchial character. In Cyclops the maxillae are very 

 small in all their parts ; in the GalmiidcE, on the 

 contrary, they are largely developed and possess 

 numerous plumose filaments (Plate I, fig. 6) ; in the 

 Notodeljyhyidce, also, the filamentous appendages are 

 large (e.g. Plate XXIX, fig. 5). The Harpacticidce 



* The homologies of the mouth-organs in this group have been dis- 

 cussed by Olaus, Thorell, Buchholz, and others. The subject is not 

 without difficulty, and is treated under the description of the Siphono- 

 stoma (p. 26) at greater length than would be suitable in this prefatory 

 notice. 



