4 
392 Proceedings of the Royal Irish Academy. 
the middle, converging at the attenuated extremities ; striee obviously ~ 
moniliform ; length, about ‘0056, breadth, about 0024. (Plate 33, 
ioe 2) 
This form was first described by Wm. Smith, who doubtfully 
considered it a sporangial variety of Navicula elliptica, BD. Yous, 
p. 48, Pl. xvu., fig. 152 a. Subsequently the same author regarded 
it as identical with Navicula lyra, Ehr.> B.D: Vol. u., -p: 93: but 
judging by the figure which Kiitzing has given of the latter, there 
can be little doubt that the forms are not altogether identical. Still, 
so similar are they, that it seems desirable to represent them as 
merely varieties. Schmidt, Atlas der Diat., T. u1. fig. 29. 
Stomachs of Ascidians, Belfast Lough. Stomachs of Ascidians, 
Kilkee, Co. Clare. Arran Islands; Stomachs of Ascidians, Roundstone 
Bay; Stomachs of Ascidians, Broadhaven Bay, Co. Galway. Bally- 
sodare, Co. Shgo. Bannow, Co. Wexford. 
Var. grunovit, (O’Meara), Marine. 
Valve broadly elliptical; marginal band of strie very broad; 
inner band of striz narrow; intermediate space between the inner 
and outer bands of striae narrow, converging, and anastomosing at the 
ends; striz very close, radiate, minutely punctate ; length 0028, 
breadth 0015. (Plate 33, fig. 3.) 
Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, 
p. 5382, T. v., fig. 22. The author just named regards the form as 
identical with Navicula Lyra, Ehr., as described by Kiitzing, Bac., 
p. 96, T. xxvii., fig. 55; but comparison of specimens of both will 
convince the observer that the forms are not identical; so distinct are 
their details that the present form might almost be regarded as entitled 
to a distinctive specific name. 
Arran Islands; Stomachs of Ascidians, Broadhayen Bay ; Stomachs 
of Ascidians, Roundstone Bay, Co. Galway. 
Var. minor, (Grnnow). Marine. 
This variety resembles that last described, but differs from it in 
the following characters; the form is much smaller, the ends are broadly 
rounded, and the lyrate space between the two bands of striz is much 
more convex ; length :0015, breadth .0009. (Plate 33, fig. 4.) 
Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, 
p. 532, Pl. v., fig. 23. 
Stomachs of Ascidians, Roundstone Bay ; Arran Islands, Co. 
Galway. 
Var. forcipata, (Greville). Marine. 
Valve elliptical, oblong; marginal and inner bands of strie sepa- 
rated by a broad lyrate, blank space ; convergent at the ends; strie, 
minutely moniliform; length about -0024, breadth about -0010. 
Greville, Q. J. M. 8. 1859, p. 88, Pl. vi., figs. 10, 11. Ralfs, in 
Pritch., p. 897. Rab. Fl. Eur., Alg., sect.1., p, 178. Donkin, N. H. 
