135 



dactylus wanting. (Inathopoda comparatively feeble in structure, propodos 

 of the anterior ones simple, without any distinctly defined palmar edge, tli;ii 

 of the posterior ones forming, at the tip, a minute chela, The 2 anterior pairs 

 of pereiopoda comparatively robust, carpal joint having, posteriorly, a rounded 

 lamellar expansion, propodal joint constricted at the base, outer part obtusely 

 rounded. The 3 posterior pairs of pereiopoda very largely developed, with 

 the basal, meral and carpal joints expanded to scale-like pieces, Hanking the 

 sides of the animal. Dactylus wanting in all the pereiopoda. Pleopoda 

 poorly developed. Uropoda rather dissimilar in structure, 1st pair compara- 

 tively strong, with both rami coarsely spinous at the truncated tips; 2nd 

 pair much smaller, with the rami setous ; last pair with the rami slender 

 linear, the outer biarticulate, and longer than the inner, both setous at the 

 tip. Telson forming a broad plate slightly incised in the middle. 



Remarks. - Of the several names assigned to this genus, that of 

 Haustorins proposed by Statins Muller is by far the oldest, and should there- 

 fore, as pointed out by the Rev. Mr. Stebbing, according to the laws of 

 priority, be preferred, though its adjective termination would seem to be less 

 appropriate. Boeck referred the genus to his subfamily Phoxince, and Dr. 

 Bovallius has subsequently proposed for its reception a new subfamily Ptery- 

 gocerinn. In my opinion it should more properly be referred to the Ponto- 

 poreiidce, exhibiting, as it does, several points of evident agreement on the one 

 side with such true Pontoporeiidse as the genus Priscilla, on the other with 

 the genus Urothoe, now generally referred to the same family. The genus 

 comprises, as yet, but a single species, though it may perhaps be questioned 

 whether the Lepidactylis dytiscus of Say is the same species as the European 

 form here described. 



9. Hailstorms arenarius, (Slabber). 



(PI 46). 

 Oniscus arenarius, Slabber, Natuurkundige Verlustigingen etc. p. 92, PI. 11, fig. 34. 



Body very tumid, with broadly vaulted back. Ceplialon about the 

 length of the first 2 segments of mesosome combined, much depressed in its 

 anterior part, rostral projection short triangular, lateral corners lying nearly 

 in the sanie plan as the former, acute. The 4 anterior pairs of coxal plates 

 considerably deeper than the body and successively increasing in si/e posteriorly: 

 4th pair subtruncated at the tip and very slightly emarginatcd posteriorly; 

 5th pair almost twice as broad as it is deep; 6th pair oblique, with the posterior 

 lobe considerably deeper than the anterior. Last segment of metasome much 

 larger than the other two, and flattened above, epimeral plates rounded, with 



