76 Transactions. — Zoology. 



on the inner anterior angle of the inner joint of the last pair of pleopoda. 

 Its function, doubtless, is to admit water to the branchial plates, and at the 

 same time to prevent the ingress of sand or other extraneous matter, the 

 flow of water is no doubt kept up by the movement of the branchial plates 

 themselves. 



All round the outer edge of the coxa?, the expanded joints of the antenna? 

 and the last pair of pleopoda, two distinct parallel borders are to be seen, 

 the outer part of the integument being apparently produced beyond the 

 inner and more opaque parts. From the inner line numerous short setse 

 arise, these seldom reach much beyond the outer line. (See figs. 5 a, b, k.) 

 Genus Limnoria, Leach. 

 (Bate's and Westwood's British Sessile-eyed Crustacea, vol. ii., p. 349.) 



As this genus is new to New Zealand I quote here the generic characters. 



"Oblong-ovate, depressed; antenna? subequal, cylindrical, not longer 

 than the cephalon. Pereiopoda nearly alike, slender. Pleon six-jointed. 

 Branchial plates naked. Terminal segment large, semicircular, with a 

 lateral appendage on each side bearing two terminal slender styles." 

 Limnoria segnis, sp. nov. PL II., fig. 1. 



Body covered with short seta?. Eyes large. Neither antenna longer 

 than head, inner one stouter and longer than the outer, consisting of three 

 joints, of which the second is the shortest, followed by a short flagellum of 

 about three joints bearing seta? and long simple auditory cilia. Lower 

 (outer) antenna? of four joints, the third and fourth subequal and longer 

 than the first and second ; followed by a short flagellum of three joints 

 bearing simple seta?. Mandible strong, appendage small, apparently of 

 only two joints, the last tipped with a few seta?. Maxillipedes similar to 

 those of L. lignorum, but having the plate at base much longer, narrower at 

 base than towards the distal end, extremity rounded, whole margin fringed 

 with short seta?. Terminal segment of the tail entire rounded and flattened, 

 without central dorsal carina and with the margins not raised. Last 

 pleopoda with the inner branch strong, about twice as long as broad, the 

 end and outer margin supplied with seta? about as long as the joint ; outer 

 branch small pointed at the end, and with two or three seta? on the outer 

 edge near the end. 



Length — ^ of an inch. 



Colour — white, opaque. 



Hab. On seaweed, Lyttelton Harbour. 



This species is very near Limnoria lignorum, the dreaded " Gribble " 

 of Europe, but it differs in several small points already mentioned. It also 

 differs in habits ; L. lignorum burrows into the wood of piers, piles, etc. ; 

 but L. segnis I found on the roots of Macrocystis. It is very sluggish and 



