189 



Legion, Monocarpinea. 

 Family, Pontoniid^. 

 BorradaUe, Ann. and Mag. Nat. Hist. Ser. 7, vol. ii., p. 37G. 

 Genus rantonia, Latreille. 



Pontonia minuta, n. sp. PL xxiv., tigs. 0-12. 



Tha body is short, moderately robust, the pleon rather 

 more bulky than the thorax in the female. 



The carapace is about as long as the first four segments 

 of the pleon, much broader than deep, with a triangular, sub- 

 acute, infra-ocular tooth, and with the antero-lateral angles 

 projecting a little beyond the base of the antennal scale, and 

 also subacute. The postero-lateral lobe overlaps the first seg- 

 ment of the pleon. The rostrum is short, entire, depressed 

 broad dorsally, rather obtusa at the apex, with a faint, broad 

 median ridge, which scarcely extends on to the carapace, and 

 i?. slightly pinched between the eyes, it has lateral sinuate 

 lidgss continuous with the orbits behind, and is rather deeply 

 carinate below, even at the distal end, it reaches rather more 

 than twice the length of the ophthalmopods. 



The pleon is smooth and considerably narrowed behind 

 in both directions, the terga of the second, third, and fourth 

 segments are subequal in length, the first and fifth shorter, 

 the sixth very short and narrow, with rather obtuse postero- 

 lateral angles. 



The telson is rather broad and regularly tapering, round- 

 ed clistally, and scarcely fringed at the end, about two and a 

 half times as long as the sixth segment of the pleon, with a 

 broad, longitudinal sulcation, reaching quite to the end, it 

 bears the usual quadrately placed spines, which are rather 

 low down, and near the margin and scarcely project. 



The ophthalmopods are short, without ocelli. 



The antennular peduncle is a little longer than the ros- 

 trum, it is strong, the first joint is hollowed a little above, and 

 has a very small stylooerite, the second joint is conspicuous, 

 but the third is very small; the upper flagellum is about as 

 long as the peduncle, and is folded back above, it is thick 

 proximally, but soon tapers to a distal slender portion on the 

 thickened portion, the sensory filaments are long and numer- 

 ous, it is one-branched — or the splitting is very obscure : the 

 lower flagellum is very short, and projects normally. 



The antennal scale is rather ovate, it reaches as far as 

 the antennular peduncle, the external distal spine is strong, 

 terminating a thickened outer margin, it is subterminal in re- 

 lation to the lamellar portion, the peduncle reaches as far as 

 the scale; the flagellum is short and curves backwards. 



The third maxillipeds are suboperculiform, of the three 

 joints of the endopod the first is stout and compressed or ex- 



