1X74 CRUSTACEA. 



coalesced in one. The six joints preceding the geniculating joint are 

 a little enlarged to contain the flexor muscle. Near the base of the 

 antennae there are three short stout spinules. 



Family II. CYCLOPILW 



The Cyclopidae are closely related to the Calanidae. In some 

 species, the mandibular and maxillary palpi are considerably deve- 

 loped, and show forms similar to those of the preceding family, 

 although these parts are always much less prominent and the setae less 

 spreading. The subprehensile character of the first pair of legs, at times 

 becoming perfectly prehensile with a well-formed monodactyle hand, is 

 the more striking characteristic of the family; for in the Calanidae these 

 legs never have this character. In this peculiarity, they resemble the 

 Corycaddce. They also often have appendages to the first or second 

 abdominal segment, which do not occur in any Calanidae. 



The eyes are situated on a single spot of pigment, which is some- 

 times subquadrate in form. The inferior eyes are not found in this 

 family. 



The cephalothorax is either four- or five-jointed. These segments, 

 as shown in figures 1 B, 2, and 8 (Plate 70) never include the seventh, 

 which is common in Pontella, neither is the first or cephalic segment 

 separated from the following by the suture a in any observed species 

 of the group ; and it is rarely the case that a suture b is present, 

 shown in figure 2, by which method alone the number of segments 

 becomes Jive. In this case, according to a figure by Philippi, of a 

 species of his genus Laophon, the anterior of the five segments bears 

 the two pairs of antennae, the mandibles, one pair of maxillae, one 

 pair of maxillipeds, and the anterior feet ; the second segment and 

 the following three bear each a pair of legs. There does not appear 

 to be the same variations in the number of thoracic articulations 

 among closely similar species in this family as in the Calanidae : on 

 the contrary, there is a remarkable constancy among the species of a 

 given type ; and, consequently, the number of segments may be used 

 as a generic character. 



