new Family of Crustacea Isopoda. 67 



this island (the south island of New Zealand), two more 

 specimens of this species were taken in about 40 fathoms. 



A superficial examination satisfied me that the species was 

 not an Tdotea at all, while a closer inspection showed that, 

 while belonging to the tribe Valvifera, it did not come under 

 any of the existing families — Idotheidse, Arcturid&e^ or Gheeti- 

 liidaj — differing from them in the possession of a 3-jointed 

 palp on the mandibles. I have therefore to institute not only 

 a w&w genus, but a new family. At the suggestion of my 

 friend the Rev. T. 11. R. Stebbing I have named it Holo- 

 gnathus {o\o<i and <yvd6o<;). 



Tribe V A L V I F E E A. 



Family Holognathidae. 



Resembles Idotheidte in general appearance, but the 

 mandibles bear a 3-jointed palp. 



Genus Holognathus, nov. 



Body elongated, depressed ; coxal plates well defined, 

 except in first segment of mesosome. Gephalon distinctly 

 divided into two parts by a transverse fissure ; posterior 

 portion short. Abdomen 5-jointed, four small joints pre- 

 ceding the large terminal one. Eyes distinct, lateral, 

 Superior antennae 4-iointed ; inferior antennas pediform, 

 flagellum 1-jointed. Mandibles strong, with the cutting-edge 

 produced into an acute lobe, molar tubercle well developed ; 

 ])alp 3-jointed. JM axillae normal. Maxillipeds with a 

 5-jointed palp. Legs stout, somewhat uniform in structure ; 

 claw strong, hook-like, and unequally bidentate at the apex. 

 Anterior pairs of pleopoda with smooth broad lamellas ; two 

 posterior pairs with setose branches. Uropoda lamellar, 

 valve-like ; outer part cut off by a transverse suture and 

 bearing a second setose plate on the inner face. Incubatory 

 pouch normal. 



Ilulog natlius Stewarti, Filhol. (PI. I.) 



1885. Idotea Stewarti, Filliol, Mission de I'lle Campbell, p. 492, pi, liii, 

 figs. 8 & 9. 



The body is elongated, that of the male being 40 mm, long 

 and 11 mm. broad, of nearly even width throughout, con- 

 vexly rounded above. 



The cephalon has the front margin nearly transverse, very 

 slightly hollowed in the middle, and slightly produced at the 



5* 



