A FINE FAMILY 339 



Family 3. — GymotJwidce. 



In contrast with the two preceding families the 

 Cymothoid*, in the comprehensive sense of the term, 

 would form a truly gigantic group. It is best, therefore, 

 to accept the arrangement which breaks it up into at least 

 six families, the animals in which are united in having in 

 most cases a similar outward facies. These six families 

 are the Cirolanidse, Oorallanidse, Alcironidae, Bary- 

 brotidse, ^gid?e, and Cymothoida3. It is common to them 

 all to have all the segments of the pera3on distinct and 

 well developed ; to have a well-developed ' palp ' but no 

 proper molar to the mandibles, the maxillipeds with the 

 epipod short and coalesced to the underside of the head, 

 and the plate of the second joint short or wanting ; the 

 first joint of the first gnathopods fused with the segment ; 

 the last four pairs of perasopods always longer than the 

 three preceding pairs of limbs, and the pleopods alike in 

 the two sexes, except for the presence of a stilet on the 

 second pair of the male. In the young there are six pleon- 

 segments distinct, of which the terminal one which includes 

 the telson is large. The pleopods generally have the 

 branches fringed with hairs, always excepting the inner 

 branch of the fifth pair ; in the first four pairs there are 

 coupling-hooks on the broad peduncles. In the gravid 

 female there are five pairs of marsupial plates on the first 

 five pairs of limbs of the perseon, and small supplementary 

 plates on the last two pairs ; the maxillipeds have fringed 

 expansions of the epipod and the first two joints, more or 

 less covered by the front marsupial plates, and evidently de- 

 signed to promote the steady influx of water upon the eggs. 



Considering that in this group a father, mother, and 

 child might in some cases readily be mistaken for speci- 

 mens of three separate species, and that among the families 

 the similarities and dissimilarities are often alike perplexing, 

 the student has great reason to be grateful to Dr. H. J. 

 Hansen, of Copenhagen, who in his admirable work on this 

 subject has provided efficient clues to the labyrinth. The 

 annexed table is translated from his treatise. 



