GENEEAL ANATOMY. 11 



it is equal in size to tlie primary branch, and may be 

 numerously jointed (Longipedia, Galanidce, Misoi^h- 

 riidce). In GydojpidcB the secondary branch is want- 

 ing, and in most of the Harpadicidce it is reduced to 

 small dimensions or, in some few cases, is quite absent. 

 The Hmb is generally curvate, dilated at the apex, and 

 provided with numerous curved or geniculated setse at 

 the extremities and over the margins of both branches. 

 In the Pcecilostoma and Si^pJiono stoma it consists of 

 only one branch, which in the male of the Gorycceidce 

 (Plate LXXXIII, figs. 13, 14) is powerfully clawed, 

 and is used chiefly as a prehensile and clasping 

 organ. 



The mandible consists, in its fully developed form, 

 of a masticating portion and a " palp ;" the first-named 

 division is in the form of an elongated, more or less 

 triangular plate, dilated at the distal extremity and 

 cut up into a variable number of tooth-like processes, 

 these being sometimes only slight serrations, some- 

 times large and powerful. The palp is variously 

 formed; in the Calanidce, most of the Karpacticidce, 

 and in many Cyclopidce, it is composed usually of a 

 large basal joint, from which spring one or two 

 small setif erous branches ; these branches are generally 

 1- or 2-jointed, but may be absent altogether. In the 

 sub-families PorcellidiincB and Id^ince the setiferous 

 portions of the organ are very largely developed, form- 

 ing large laminated appendages, which are fringed 

 with densely ciliated filaments (Plate LXYIII, fig. 4 ; 

 Plate LXIX, fig. 11). In the genus Cyclops, while 

 the biting part of the mandible is well developed, 



