GENERAL AXATOMY. 9 



antennae are frequently armed with denticulated plates, 

 giving a firmer grasp. A very remarkable instance of 

 this structure exists in Gandace pectinata (Plate X, 

 fig. 2), also in the genera Centropages, Pontella, Para- 

 pontella, &c. ; other genera, such as Temora and 

 Diaptomus (Plate VI, fig. 7), are provided with one or 

 more strong spines in lieu of, or in addition to, the 

 denticulated plates. These spines are situated at 

 various points of the internal surface of the antenna 

 above the hinge-joint, and the limb itself is more or 

 less swollen in the same situation to give room for a 

 powerful flexor muscle. In the Pontellince this enlarge- 

 ment of the limb is excessive (Plate X A, fig. 2 ; Plate 

 XI, fig. 2). In the males of many Calanidce, however, 

 there is little or no difference of form between the 

 antennae of the two sides ; the difference is very slight 

 also in the Misophriidce. In most Cyclopidce there are 

 found differences of a kind similar to those already 

 described, but affecting equally both right and left 

 antenna (Plate XVII, fig. 5 ; Plate XXII, fig. 16) ; 

 there are here no denticulated plates and few spines, 

 but the limb is distinctly geniculated near the base as 

 well as near the apex, and the articulations of the 

 terminal segments are likewise very mobile. Amongst 

 the Notodelphyidce the structure of the male antennas 

 is somewhat similar to that of the Cyclopidce, but by 

 no means so well marked. In the Harpadicidce, where 

 the anterior antenna are very much smaller in com- 

 parison with the size of the animal, the hingement of 

 the male organ is not quite so obvious, though still 

 sometimes quite of Cyclopid type (Cantlwcamptus 



