•326 Proceedings of the Royal Irish Academy. 



Mastogloia closeii, K. S. Marine or brackish water. 



Yalve somewhat rhomboid ; length -0018; breadth "0008; ends 

 narrow, lanceolate ; median line straight ; central nodule very small ; 

 marginal plates wide in the middle for a short space, and rapidly 

 attenuated long before reaching the ends ; loculi generally four in 

 number, two large in the middle, and one at either side narrow, at- 

 tenuated ; space between the inner margin of plates wide, shaped 

 somewhat like an hour-glass, with pointed ends ; striae fine, linear, 

 radiate, reaching the median line. (PI. 29, fig. 10.) 



Found first in a gathering by Eev. Maxwell H. Close, from rock 

 pools in the bay called Lough Kay, between Cahirciveen and Doulus 

 Sead, Co. Kerry. Lough Gill, Co. Kerry. Sea-weeds, Giants' Cause- 

 way, Co. Antrim. 



Mastogloia p or tier ana, (Grunow.) Marine. 



Yalves narrow, lanceolate ; slightly produced at the apex ; mar- 

 ginal plates narrow ; gradually attenuated towards the ends ; loculi 

 numerous; striae very obscure. (PI. 29, fig. 11.) 



This form is very similar in some respects to large specimens of 

 Mastogloia lanceolata, but differs in many details ; it is longer, and 

 proportionately narrower ; the sulci at either side of median line in 

 the case of M. lanceolata are absent in this ; the apices, too, arc 

 slightly produced, and the striae much finer than in that species. 

 Grunow states that, with an amplifying power of 400 times, the strisc 

 are scarcely noticeable ; but in the several specimens examined by mc 

 with a one-eighth objective and deep eye-piece, the striae could not be 

 •discovered. Grunow, Verhand. der K. K. Zool. Bot. Gesel., Band xii. ; 

 1863, p. 157, T. iv., fig. 13. Eab. Tl. Eur., sect. 1, p. 236. 



From stomachs of Ascidians, Eoundstone Bay, Co. Galway. 



Mastogloia danseii, (Thwaites.) Marine or brackish water. 



Yalve linear, elliptical ; broadly rounded at ends ; striae reaching 

 the median line, but slightly shortened around the central nodule ; 

 radiate, formed of close puncta ; marginal plates on inner margin 

 straight till near the ends, where they are suddenly attenuated ; 

 loculi numerous, parallel ; space between the plates narrow, and 

 slightly expanded at the ends. 



Wm. Sm., B. D., Yol. ii., p. 64, Supp. PI. Ixii., fig. 388. Ealfs, 

 in Pritch., p. 924, PI. xv., fig. 30. Grunow, Yerhand. der K. K. 

 Zool. Bot. Gesel., Band x., 1860, p. 576. Kab. Fl. Eur., sect. 1, 

 p. 26 1 . — Dickiea danseii, Thwaites, Ann. Nat. Hist., March, 1 848, p. 1 71 . 

 Smith seems to think that this species hardly differs from Mastogloia 

 lanceolata, but a careful consideration of the two forms will, I think, 

 prove that in all the details they are essentially different. 



Tacumshane, Co. Wexford. Lough Foyle, Co. Londonderry'. 

 Larne, Co. Antrim. Salt marsh, Kilcool, Co. Wicklow. 



