284 THE VOYAGE OF H.M.S. CHALLENGER. 



Haliporus, 1 Spence Bate. 

 Haliporus, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol. viii. p. 185, September 1881. 



Carapace submembranous, dorsal surface carinated, anteriorly produced to a rostrum. 

 Frontal margin armed with an anteriorly projecting point or flattened tooth, correspond- 

 ing with the outer side of the first pair of antenna?, and a second in a line behind it, with 

 another tooth projecting outwards and forwards, corresponding with the outer side of the 

 second pair of antennae, and a fourth tooth on the inner side corresponding to the 

 anterior portion of the hepatic region. The cervical suture is strongly defined upon the 

 dorsal surface. 



The pleon is laterally compressed, and the telson is long, slender, and laterally 

 compressed. 



The ophthalmopod is single-jointed and supports a small tubercle on the inner 

 margin. 



The first pair of antennae carries only a short prosartema, and the stylocerite 

 is short and stout. The peduncle is long, and so are the flagella, which in all 

 probability are cylindrical as in other species, but are broken off in this the type- 

 specimen. 



The second pair of antennae carries a long and narrow scaphocerite and a long and 

 slender flagellum. 



The mandibles carry a long two-jointed synaphipod ; the first joint is ovate and 

 reaches as far as the frontal margin, the second is narrow and reaches as far forwards as 

 the extremity of the peduncle of the second pair of antennae. 



The first pair of gnathopoda is subpediform and carries a short basecphysis. 



The second pair is long and pediform, and carries only the rudiment of a basecphysis. 



The pereiopoda are long and devoid of a basecphysis. 



The branchiae consist of rather small and delicate plumes, and may be tabulated as 

 follows : — 



Pleurobranchiae, 

 Arthrobranchiae, 

 Podobranchias, 

 Mastigobranchiae, 



In general appearance the species of this genus are more slender and membranous 

 than in either Solenocera or Philonicus, and the appendages are longer. 



The arrangement of the branchiae is very nearly the same as in Philonicus but the 

 mastigobranchial plates are much larger and more leaf-like, and extend farther between 

 the plumes ; one or two of the anterior plates carry a rudimentary podobranchial plume. 

 The flagella of the first pair of antennae are both cylindrical, there being no groove in 



1 From aXwo'jof, going through the sea. 



