O'Meara — Heporf on the Irish Diafomacece. 373 



Navicida johnsonii, (AYm. Sm.) Maiine. 



Yalve long and narroTV' ; length, "0060 ; breath, 'OOOo ; inflated in 

 the middle and at the ends ; transverse striae very fine, parallel, longi- 

 tudinal striae more easily detected; colour of diy valve "whitish. 

 (PI. 31, fig. 46.) 



Pinnulariajohisonii, ^'m. Sm. B. D., Yol. i., p. 58, PL xix., fig. 

 1 79. Eab. PI. Enr. Alg., sect, i., p. 211. Rahenhorst considers the form 

 identical Tvith Xavicnla scopiilornni, De Brebisson. In this opinion he 

 agrees -svith Ralfs, in Pntch., p. 895, andDonkin, iS". H. Brit. Diat., p. 73, 

 Pl.xii.,fig. 5. I cannot find any figure of De Brebisson' s species, Xavicula 

 scopulorum, and consider the identification of the last named Tvith the 

 present species more than doiibtful, inasmuch as Kiitzing regards that 

 form as identical with Xavicula mesotyla, figiu'cd by him, Bac, T. v., 

 fig. 3, and T. xxviii., fig. 84. These figures are obscure as to details, 

 but from the size and outline I 'would think it impossible to confound 

 jS^avicula johnsonii with them, and therefore I attribute the species to 

 Smith, who has described and figured it with unmistakable accuracy. 

 This coiu-se commends itself the more to my judgment, inasmuch as 

 G-ninow has described and figured under the name of Xavicula scopu- 

 lorum a form which is obviously distinct fi'om that under considera- 

 tion. 



Bannow, Co. YTexford. Malahide, Portmamock, Co. Dublin. 

 Mouth of the Biver Xannywater, Laytown, Co. Meath. 



Navicula simulans, (Donkin). Marine. 



Yalve linear, with long cuneate ends ; transverse striae very faint ; 

 longitudinal striae quite noticeable with good illumination, if the valve 

 be dry ; longitudinal free space nan-ow, except in the middle, where 

 it spreads out to the margin in a narrow staui'of oite band ; length 

 •0030, breadth -0006. (Plate 31, fig. 47.) 



The present species I consider to be identical with that so named 

 by Donkin, ]N^. H. Brit. Diat., p. 60, PL ix, fig. 3. Donkin considers 

 it the same as Amphiprora constricta, Ehr., but in this opinion I can- 

 not concur. Donkin does not notice the longitudinal striae ; but in all 

 other respects the present form is, in my mind, not distinguishable 

 fi'om the species named IS^avicula simulans by that author. 



Stomachs of Ascidians, Broadhaven Bay, Co. Galway. Malahide, 

 Co. Dublin. 



Navicida delginensis, ^N". S. Marine. 



Yalve rhomboid, gradually attenuated towards the broadly rounded 

 ends ; transverse striae very faint ; longitudinal striae easily detected, 

 more especially at the margin, where there is a strongly marked sul- 

 cus ; intermediate free space narrow, lanceolate towards the ends, and 

 slightly expanded in the middle ; length '0020 ; breadth in the mid- 

 dle -0006. (PL 31, fig. 48.) 



This form is in outline very similar to a species described and 



