DUBLIN NATTJEAL HISTOEY SOCIETY. 157 



The abdomen consists of five segments. The first, or that nearest 

 the cephalo-thorax, with a protuberance about half-way down, and fur- 

 nished with a hair (represented as a spine by the artist) at its inferior 

 external angle; this joint is somewhat quadrilateral. The second, 

 third, and fourth decrease gradually in size, and the terminal joint ends 

 in a semilunar tail (Fig. 6, back view, magnified 350 diameters) fur- 

 nished with six tubular spines, each distinctly articulated to a jointed 

 peduncle ; the edges of these spines are finely serrately ciliate, and the 

 internal pairs furnished internally each with three hollow spines com- 

 municating with the cavity of the primary spine ; a short spine is also 

 found at the origin of each semilunar arm ; a plate of very peculiar 

 form arises from the articulation of the fourth and fifth joint posteriorly, 

 and projects below the termination of the tail ; in other particulars my 

 specimens agree with J. V. Thompson's descriptions. 



The circulation, as seen under a power of 350 diameters, is ex- 

 tremely curious : a closed (?) pulsatile vessel running down the back, 

 with dilatations at each articulation ; in this a regular flux and reflux of 

 fluid might be seen, accompanied by dilatations and contractions of the 

 dilated portions. Besides this, a regular circulation, whose course was 

 not easy to make out, was to be seen passing along the sides and through 

 the horns, and even into the three little hollow spines with which the 

 caudal primary spines were furnished. , 



Antrim (W. T.), Dublin, Dingle (W. Andrews), Lahinch (W. T.), 

 Galway (A. G. M.), Eoundstone (W. M'C.) 



Ehalia Pennantii. — Bray, May, 1857, Scallop bed. The late Robert 

 Ball, LL. D., showed me a specimen from Dalkey. 



Belfast (0. C), Dublin, Cork (C. C. S., J. V. T.), Galway (A. G. M.), 

 Eoundstone (W, M'C). 



Pagurus Icevis. — "What I take to be this species has occurred to me 

 both in Dalkey and also at Bray ; it differs from P. Hyndmanni chiefly 

 in the comparative length of chelae. 



Portaferry (W. T.), Dublin (?), Galway (A. G. M.). 



Galathea nexa. — A small species, which I take to be this, occurs 

 pretty plentifully in Dalkey Sound and Bray, in 12-30 fathoms; it 

 spawns in March, April, and May. 



As contrasted with Galathea squamifera, the following points call 

 for notice : — 



Bostrum short, furnished with four flattened, hollowed teeth on 

 each side; the hindmost pair situated on the orbit. (In Gal. squa- 

 mifera, five spines, the hindmost two as G. nexa). Anterior pair of legs 

 narrowed, elongate, covered with a few tubercles, terminating, for the 

 most part, in a single spine ; some, however, pass into denticulate squa- 

 ma? : these tubercles are arranged on the hands in nearly parallel longi- 

 tudinal lines, contrasting with the densely squamiferous anterior limbs 

 of G. squamifera. The hands are narrow and elongate, the fingers nearly 

 'parallel, finely denticulate, scarcely hairy, terminating in a fine nail ; 

 they are slightly spinous on the exterior. External foot-jaws, second 

 joint equalling third. The description of G. nexa, in Bell, is so sue- 



