224 Rev. T. Hincks on the 



Zocecia ovate, quincuncial, decidedly convex, depressed 

 below, and rising rather abruptly towards the oral region ; 

 surface white and shining, smooth (in young cells) or slightly 

 roughened, in some states areolated, delicate costaj passing 

 upward from the margin to the base of the avicularian umbo ; 

 primary orifice semicircular ; immediately below it, placed 

 centrally, an erect process, expanded below, narrowing 

 slightly upward and bending in towards the orifice (which it 

 sometimes overhangs slightly), bearing on its summit a cir- 

 cular aviculariumj immediately behind which rises a short 

 mucro I peristome in the adult cell elevated, especially in 

 front, embracing the avicularium. Ooecium prominent, rounded 

 above, broader than high, flattened in front, surface minutely 

 pitted over (in the young state smooth, glassy, emarginate), 

 commonly a small elongate fissure on the front. 



Var. With a smaller avicularian process on each side of the 

 central one and close to it, or sometimes only on one side 

 (PI. XIV. fig. 4). 



Hab, On shells and Ilydroida, in small patches. 



The Eschara verrucosa of Smitt is certainly not identical 

 with the Lepralia t;crrMCosa of Johnston, Busk, &c., to Avhich 

 he at first referred it. The latter is a much larger species, 

 witli an orifice of a totally different structure. lie subse- 

 quently ranked it as a form oi Eschara cervicornis { = PoreUa 

 compressa^ Sowerby) . 



I am by no means sure that I am right in identifying it 

 with the present species. Prof. Smitt has given us a very 

 brief description of it, and unfortunately his figure is too 

 small to be of much service. At the same time I think it 

 more than probable that the two are ideiitical. The present 

 form is clearly a Porella. It differs indeed from most of the 

 species of this genus in the costate condition of the front wall 

 of tlie zooecium (though we meet with it in P. stru?na, Nor- 

 man) ; but in all essential points its structure allies it to this 

 group. One of its most distinctive characters (as a species) is 

 the elevated avicularian rostrum, which may remind us of the 

 similar structure in Umbomda verrucosa. The delicate tex- 

 ture, the silvery whiteness, the elevated front wall with the 

 radiating ribs (not always present) are also characteristic 

 features. 



Loc. St. Lawrence, Orphati Bank and off Cap Rozier, 

 38 lath. If I am right in identifying P. ■prohoscidea with 

 Smitt's species, it has also occurred iu S})itzbergen, Nova 

 Zembla, and the Peninsula of Kola. 



