46 DUBLIN NATT7EAL HISTOEY SOCIEir. 



backs, the body supported on the dorsal spine. I do not know whether 

 this is the normal position for them or not. The abdominal false feet 

 were kept in perpetual motion. 



In figure (Plate IX., Figs. 4, 5) they appear identical with zoes 

 bred by J. V. Thompson from Cane, pagurua (Zoological Researches, 

 Plate VIII., Fig. 1), as might have been expected from the close rela- 

 tionship of the genera ; indeed, I am inclined to think that the zoes of 

 the Brachyura, at least, will be found to be nearly undistinguishable, 

 the apparent difference in the figures published arising from the difficulty 

 of making perfect microscopic observations, arising from the transpa- 

 rency of the various parts. If we compare the figures here given with 

 Thompson's figure of zoea of Pinnotheres pisum (Ent. Mag., vol. iii., 

 p. 85 ; BeU's British Crustaceae, p. 125), we will at once perceive their 

 sti'ong similarity. Although I examined twenty or thirty specimens of 

 this zoe, I only succeeded twice in getting the lateral spines in full view : 

 they are represented rather too long in my figures. 



The spiny curvature was as follows : — Arising out of the centre of 

 the carapace a long, curved horn ; between the eyes a curved rostrum ; 

 on each branchial region a short scimitar- shaped horn; and lastly, a very 

 short, slender, hollow horn, arising from the posterior edge of the cara- 

 pace at its junction with the abdomen. Three fine hairs, also, are found 

 arranged in a line along the median line of the carapace posteriorly. 



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 veiy 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. Y. 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 primaiy spines were furnished. 



Antrim (\V. T.), DubHn, Dmgle (W. Andrews), Lahinch (W. T.), 

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



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

 Ball, LL. D., showed mo. a specimen from Dalkcy. 



