

GENERAL ANATOMY. 13 



have the maxillas very small, but numerously divided ; 

 there is usually a chewing portion pretty strongly 

 toothed, and a palp which is divided into two or 

 three setiferous digits, and has likewise two lateral 

 (? branchial) offshoots (Plate LYII, fig. 2, Plate LX, 

 fig. 6, Plate LXII, fig. 5, &c.), but this arrangement 

 is subject to endless variation as to the number and 

 development of the various parts. In parasitic species 

 the maxillae, though usually present, are often atro- 

 phied, and in the semi-parasitic forms belonging to 

 the groups Pcecilostcma and Siphonostoma, are ex- 

 tremely minute, and sometimes attached to the base 

 of the mandibles. 



The anterior and posterior foot-jaws (which are in 

 reality only the exo- and endo-podites of a single 

 somitic appendage) do not present features requiring 

 any lengthened description. They are in all cases 

 adapted for prehension. In the Calanidce, Cyclopidce, 

 and Notodelphyidce, the two pairs are not very dissimilar 

 in structure, consisting generally of from four to six 

 joints, which are in most cases marginally produced 

 into digitiform or wart-like eminences on their inner 

 side, and are more or less densely setiferous. In the 

 Harpacticidce, while the first foot-jaw is like those of 

 the preceding families, the second is usually in the 

 form of a strongly-clawed hand, and in some sub- 

 families (Tdyince, &c.) both pairs assume this cha- 

 racter; such, also, is the case in the semi-parasitic 

 Pcecilostoma and Siphonostoma. The subfamily Longi- 

 pediince, unlike the rest of the Harpacticidce, has the 

 posterior foot-jaw destitute of a clawed hand, those 



