398 A HISTOEY OF EECENT CEUSTACEA 



appeared to be two males fixed one on each side of the 

 female. 



Family 3. — Dajidce. 



They are parasitic on Schizopoda. In the adult female 

 the trunk-feet are only five pairs, and the sides of the 

 body are folded ventrally so as to form a chief part of the 

 marsupium, only the last pair of marsupial lamellae re- 

 taining an important function in closing the pouch from 

 behind. 



Dajns, Kroyer, 1846. The animals of this genus are 

 attached on the ventral side of the host. In the female, 

 the first antennas are tuberculiform, three-jointed, the two 

 terminal joints minute ; the second antennae have a large 

 basal joint, succeeded by about eight slender joints. The 

 spoon-shaped ends of the mandibles can be projected 

 through an opening between the upper and lower lips. 

 Both pairs of maxillge are rudimentary, tubercular. The 

 maxillipeds are two-jointed, with an epipod, but no 

 exopod. Between them is developed a triangular opercu- 

 liform plate. The sixth and seventh pairs of feet disap- 

 pear ; the preceding five are all nearly alike. The imbricated 

 first four pairs of marsupial plates form a movable lid to 

 the front opening of the marsupium. The large fifth pair 

 close it behind, in combination with the inner branches 

 of the first pleopods. The remaining pleopods are rudi- 

 mentary, the second, third, and fourth being bilobed, but 

 the fifth consisting of a pair of simple tubercles. The 

 uropods also are simple, but a little more elongate. The 

 adult male is placed between the first pleopods of the 

 female. It has the first segment of the pera^on fused 

 with the head ; the pleon is a single piece without pleo- 

 pods. The first antennae are four-jointed, the second 

 eleven-jointed. The mouth-organs consist of strong 

 mandibles and tubercular first maxilla and maxillipeds. 

 The male, in the earlier ' cryptoniscian stage,' has seven 

 distinct segments in the perason and six in the pleon, with 

 appendages to each, those of the pleon being all biramous, 

 with the branches set wide apart on the broad peduncle. 



