Plankton Crustacea from N^eio Zealand. 239 



Diastylis neo-zealanica, G. M. Tliomson (Journ. Linn. Soc, 

 Zool. xxiv. p. 268, pi. xviii. figs. 1-11, 1892), of which I 

 liave examined a specimen kindly sent me by Mr. Tliomsou 

 agrees closely with the present species in the form and arma- 

 ture of tlie telson and uropods, in havin^f minute exopods on 

 the third and fourth pairs of legs, and in the form of the 

 ischium of the third maxilliped (the original figure of this 

 appendage is defective in this point). The two species are 

 at once distinguished, however, by the form of the carapace, 

 which in i\Ir. Thomson's species is obli(|uely costate. 



Leptostylis sp. 



A species closely allied to, but apparently distinct from, 

 Zimmcr's Leptostylis thileniusi (Zool. Jahrb., Abth. Syst. 

 xvii. )). 4:49, 1902) is represented by a number of males (the 

 largest only 3'3 mm. in length) and a single young female. 

 As all the specimens are in poor condition, however, I do not 

 attempt to describe the species fully. It differs from that 

 described by Zimmer in having the cephalothoracic region 

 not longer than the abdomen, the third free thoracic somite 

 not strongly produced backwards at the sides, so that there is 

 only a slight interval between the second and third pairs of 

 legs, and the telson armed with only three pairs of lateral 

 spines. The two forms agree in the armature of the abdomen, 

 with ventral spines and dorsal seta?, and apparently in the 

 disposition of the ridges on the carapace, altliough these are 

 difficult to see in our specimens. They further agree in the 

 remarkable and chnracteristic structure of the third maxilli- 

 ped, which, however, I interpret somewhat differently from 

 Dr. Zimmer. The large rounded plate which he describes as 

 a process of the second segment (basis) of the limb is, 

 according to my observations, an outgrowth from the third 

 segment or ischium, and is an erdargement of the digitiforra 

 process of that segment observed in L. insularum. It is, 

 indeed, adherent along its proximal border to the distal 

 border of the basis ; but this connexion is simply a continua- 

 tion of the articulation between the basis and ischium. 



(/) Dec A PC DA. 

 P innothercs sp. 



A single male specimen belonging to this genus occurred 

 in haul 1 B. In the present state of our knowledge the 

 identification of solitary specimens of this sex appears to be 



