igisO Stanley Kemp : Crustacea Decapoda. 303 



Family PALAEMONIDAE. 



Genus Palaemon, Fabricius. 



Palaemon hcndersoni, de Man. 



(Plate xix, figs. 19-23.) 



1907. Palaemon {Parapalaemon ?) hendersoni, de Man, Trans. 



lyinn Soc, Zool. (2) IX, p. 446, pi. xxxiii, figs. 66-68. 

 1910. Bithynis {Parapalaemon) hendersoni, Rathbun, Bull. 



Mus. Comp. Zool., Harvard, IM, p. 316, pi. v, fig. 3. 



The length of the carapace and rostrum is a little less than 

 that of the abdomen, excluding the telson. The carapace, except 

 on the walls covering the branchial chamber, is closely covered 

 with very minute prickles which are easily removed by wear. 

 The anterior margin is lobed at the base of the orbit and at the 

 lower limit of this lobe there is a sharp antennal spine arising 

 close behind the edge. The hepatic spine is small (figs. 19, 20). 



The rostrum commences as a blunt, dorsal crest a little in 

 front of the middle point of the carapace and extends beyond the 

 end of the first segment of the antennular peduncle, sometimes 

 as far as the junction of the second and third segments. Dorsally 

 it bears from five to seven teeth, of which from one to three 

 (usually two) are situated on the carapace behind the longitude of 

 the posterior limit of the orbital notch. The teeth are more or 

 less evenly spaced, but the posterior one is as a rule separated by 

 a greater distance than the rest. Between the dorsal teeth are 

 numerous hairs. On its ventral margin the rostrum bears one or 

 two teeth near the apex. 



The eyes are deeply pigmented. In dorsal view a small ocellus 

 is visible, imperfectly separated from the cornea. 



The basal segment of the antennular peduncle is considerably 

 longer than the two following combined. The laminar plate, 

 which forms the outer portion of the segment, terminates in a 

 stout external tooth which reaches beyond the middle of the 

 succeeding segment ; the lateral process consists of a sharp spine 

 which extends as far forwards as the eyes. Anteriorly the inferior 

 margin of the second segment is strongly produced. The two 

 rami composing the upper (and outer) flagellum are fused basally 

 for a distance scarcely greater than the extreme length of the 

 last peduncular segment (fig. 20). 



The antennal scale is about two and a half times as long 

 as broad, and the spine which terminates the slightly convex 

 external margin does not nearly reach the broadly rounded apex 

 of the lamellar portion. 



The outer maxillipedes extend to the end of the antennular 

 peduncle ; the ultimate segment, including the corneous terminal 

 spine, is only a trifle shorter than the antepenultimate. 



The first peraeopods reach beyond the antennal scale by a 

 little more than the length of the propodus. The proportional 



