IQ22 ] 



S. Kemp : Notes on Crustacea Decapoda. 



261 



A. Dactylus of last three legs simple. 1 



B. Rostrum reaching only to middle of eyes; last two 

 segments of third maxilliped together fully as long 

 as antepenultimate segment 

 B'. Rostrum twice as long as eyes ; last two segments 

 of third maxilliped together much shorter than ante- 

 penultimate segment 

 A'. Dactylus of last three legs biunguiculate and with a 

 number of spines on its posterior margin. 

 B. Rostrum well developed ; eyes normal in form. 

 C. Penultimate segment of third maxilliped 4 time's 

 as long as wide and more than twice as long as 

 ultimate ; carpus of first leg not longer than chela ; 

 dactylus of last three legs with 1 1-13 spines behind 

 biunguiculate apex 

 C. Penultimate segment of third maxilliped 2'5 

 times as long as wide and 1*5 times as long as 

 ultimate ; carpus of first leg longer than chela ; 

 dactylus of last three legs ? 

 C". Penultimate segment of third maxilliped less 

 than twice as long as wide and shorter than ulti- 

 mate; carpus of first leg not longer than chela; 

 dactylus of last three legs with 4-6 spines behind 

 biunguiculate apex 

 B'. Rostrum rudimentary ; eyestalks flattened with 

 inner margins contiguous, bearing cornea at outer 

 distal angle 



brevirostris Miers. 



miiutta Baker, 



okai, sp. nov. 



ascidicola Borr. 



anaclwreta, sp. nov. 



quad ratophth alma 

 Balss. 



Pontonia okai, sp. nov. 



The rostrum (text-fig. 89) is toothless, broad at the base and 

 very slender at the apex which is acute in both dorsal and ventral 

 views. Dorsally it is cari- 

 nate throughout the greater 

 part of its length, but there 

 is no suggestion of a ventral 

 keel. It is curved down- 

 wards and is a little shorter 

 than the eyes, reaching about 

 to the middle of the basal 

 antennular segment. 



The carapace is consider- 

 ably depressed. It bears 

 only an antennal spine and the lower limit of the orbit is not 

 angulate. The eyes are short, with cornea slightly narrower than 

 the stalk ; the ocular spot appears to be absent. 



The antennular peduncle (text-fig. 90a) is a little shorter than 

 the antennal scale. The basal segment is broad at the base with a 

 large lanceolate lateral process which reaches the middle of its 

 length. The outer margin in front of the process is slightly 

 concave and ends in a stout tooth which reaches beyond the 

 middle of the second segment. The second segment is broader 

 than long, the third about the same length and as broad as long. 

 The free portion of the stouter ramus of the outer flagellum is ex- 

 tremely short and the fused portion comprises 3 or 4 segments. The 



Text-fig. 89. — Pontonia okai, sp. nov. 

 Anterior part of carapace, rostrum and eye. 



In P. miiutta described as "simple — or perhaps a little bifid at the tip. 



