NO. 26 NEW MYSIDACID CRUSTACEANS TATTERSALL I3 



is single-jointed and furnished with eight or nine delicate plumose 

 setae, the exopod is seven-jointed, the terminal joint furnished with 

 two long plumose setae ; in the third pair (text fig. 6c) the protopod 

 is about two and one-half times as long as broad, shorter and not so 

 stout as the protopod of the second pair and shorter than its own exo- 

 pod, endopod single-jointed and furnished with two short cur\^ed 

 spines at the apex, the exopod long and modified in the most extraor- 

 dinary way into a very complicated copulatory organ. (It is quite 

 impossible to describe this appendage intelligibly, and reference must 

 be made to the figure 6c, where all the essential processes and parts 

 are figured as accurately as possible.) The fourth and fifth pairs of 

 pleopods of the male (text figs. 6d and 6e) are very similar to one 

 another, with short rectangular protopod, a single- jointed endopod and 

 a two-jointed exopod, all furnished with the usual long plumose setae. 



Length of adults of both sexes lo mm. The female carries about 

 25 eggs in the brood pouch. 



Type.— U.S.N. M. no. 72868. 



Remarks. — The females of this species are very closely similar to 

 those of most species of the genus, differing only in minor characters. 

 The males, on the other hand, are clearly distinguished by the struc- 

 ture of the pleopods, especially those of the second and third pairs. 

 I know of no other species in which the exopod of the third pair 

 of male pleopods is modified in the same way as in this species, and 

 the form of this pleopod at once distinguishes G. johnsoni from all 

 other species of the genus. The second pair of male pleopods are 

 also much more robust than in any other species. G. johnsoni is much 

 the most remarkable species in the collection, and I have much pleasure 

 in associating it with the name of the leader of the expedition. It 

 is a very abundant species in the coastal waters of the Virgin Islands 

 and Puerto Rico, where several hundred specimens were captured 

 at night with nets. 



Subfamily Mysinae 



Tribe ERYTHROPINI 

 HYPERERYTHROPS Holt and Tattersall 

 HYPERERYTHROPS CARIBBAEA, n. sp. 



Text fig. 8 



Locality. — Serial number 573, one specimen (male). 



Description. — Carapace (text fig. 8a) hardly produced into a rostral 

 plate, front margin broadly and evenly arcuate, slightly upturned in 

 lateral view, anterolateral corners produced but rounded. 



