57 



Subfam. 2. Macrocyprinae. 



Characters of the subfamily. Shell more or less elongate, tapered behind, 

 and of rather firm consistency, apparently calcareous, with the surface smooth 

 and almost bare of hairs. Valves pronouncedly unequal, the right one over- 

 lapping the left in the middle of the dorsal face; their closure in the oral 

 region very thorough, the edges being conspicuously expanded in that place. 

 Antennae not adapted for swimming; the anterior ones with the 3 seg- 

 ments of the basal part very distinctly defined, terminal part less sharply 

 marked of from the basal one, and having the setae comparatively short. Post- 

 erior antennae, as in the Pontoey prince, distinctly 6-articulate' and armed at the 

 tip with the usual number of claws, sensory appendage of 3rd joint replaced 

 by a bundle of delicate filaments; natatory setae wholly absent. Mandibles 

 and maxillae on the whole normally developed. Maxillipeds without any vibra- 

 tory plate, masticatory lobe narrowly produced and sharply defined from the 

 basal part, palp in female sub-pediform, in male transformed in the usual manner. 

 Both pairs of legs slender, 5-articulate, but rather dissimilar, the posterior ones 

 being, as in the typical Cypridae abruptly bent upwards and concealed within 

 the shell, last joint of these legs well developed and carrying, in addition to 

 2 comparatively short setae, a remarkably elongate claw-shaped spine abruptly 

 reflexed along the leg. Caudal rami more or less imperfectly developed. Ovaria 

 and testicles not entering between the lamellae of the valves. Ejaculatory tubes in 

 male largely developed, but rather differing in structure from those in the typical 

 Cypridae, their efferent ducts also dissimilar. 



Remarks. The most prominent characters distinguishing the present sub- 

 family are derived from the genital apparatus. In the structure of the maxillipeds 

 some resemblance to the Pontocyprince is found; but the posterior legs are 

 rather dissimilar, and the caudal rami exhibit an appearance even different 

 from that in all other known Cypridae. Yet, in most of the structural details 

 the Cyprid type may be found to be well manifested. 2 closely allied genera 

 referable to the present subfamily will be treated of below, and I am of opinion, 

 that the Mediterranean form recorded by G. W. Mtiller as Macrocypris succinea 

 should more properly be regarded as the type of a 3rd genus. 



8 Crustacea. 



