DUBLIN NATT7BJLL HI8T0BT 80CIETT. 69 



three anterior segments of the pleon ; whilst on the next succeeding 

 there is a prominence as if a tooth had been arrested in the course of 

 development. 



On each side of the dorsal centre there exists a tooth, formed by the 

 projection of the posterior margin, of each of the three segments that 

 canics a central tooth, as also the last segment of the pereiarif on which 

 a central tooth does not exist. 



Lower down on each of the three anterior segments of the pleon a 

 second row of similar teeth exists on the posterior margin, and the two 

 posterior of these same have each the infero-postcrior point produced 

 into a tooth ; those upon the third segment are all curved upwards. 



The anterior pair of Gnathapoda (Fig. 5) are simple ; the dactylos 

 in this species is either rudimentary or fused with the preceding joint ; 

 the extremity of the leg is tipped with six strong hairs, curved and re- 

 versely ciliated (Fig. 5a). 



The second pair (Fig. 6), as also the mandibles (Fig. 3), and other 

 appendages of the mouth, offer no great difference from the same organs 

 in /. ohesa. 



Tclson (Fig. 7) single, notched at the apex. I have named it after 

 the place of its discovery. 



This crustacean was taken by Professor Kinahan from the gill cavi- 

 ties of Rhizostoma Cuvieri in Dublin Bay. 



There is undoubtedly much to be learned of the habits of animals 

 that are taken from deep water by the aid of the dredge ; yet from what 

 we do know I am inclined to think that the position in which Iphime- 

 dia Ehlance was taken must have been one of accident rather than its 

 natural habitat. I have never taken Iscea Montagui except on the back 

 of a crab {Maia squinado) ; and the Isopod Astacella longiccyrne infests 

 the spines of Uchtntts sphcera. But these are not parasitic in their ha- 

 bits, such as /. Ehlance we must suppose to be, if its natural abode is 

 within the walls of the gill cavities. 



EXPLANATION OF FIGIJEE8. PLATE XVI. 



Fig. 1, lateral view ; Fig. 2, dorsal ; Fig. 3, mandible ; Fig. 4, max- 

 [illiped; Figs. 5 and 5a, first gnathopod; Fig. 6, second gnathopod. 

 ~^g. 7, telson.* 



DONATIONS TO MUSEUM, MAY L 1857. 



Vere Webb Macnally, Esq. — One hundred specimens of native Le- 

 pidoptera. Nephrops Norvegicus, Dublin Bay. 



William Andrews, Esq., M. K. I. A. — Podiceps c&mutus, Lough Ca- 

 ragh, county of Kerry ; eggs of Sula hasaatM and Ardea cinerea, county 



* Eight specimens of thia species were found by me swimming merrily In the gill 

 cavities of a Khizostoma, which had been driven ashore, after a high gale, at Merrion, 

 county of Dublin, in the autumn of 1854. The specimens have been unfortunately mis- 

 laid, except that figured above, which is now imperfect.— J. R. K. 



