P)20 Proceedings of the Royal Irish Academy. 



Striafella umptmctata, (Lyng.) Marine. 

 Diagnosis same as that of the genus. (PI. 29, fig. 6.) 

 Kutz. Bac, p. 125, T. xviii., fig. 5, who considers the form 

 identical with Fragilaria nnipunctata, Lyngbye. Wm. Sm., B. J)., 

 Vol. ii., p. 36, PI. xxxix., fig. 307. Ealfs, in Pritch., p. 803, PI. iv., 

 fig. 40. Grunow, Yerhand. derK.K. Zool. Bot. Gresel., Bandxii., 1862, 

 p. 427. Heiberg, De Danske Diat., p. 72. Eab. Fl. Eur., sect. 1, 

 p. 307. Cleve, Om Svenska och !N"orska Diat., p. 222. 



Sea-weeds, Bray, Howth, Salt Hill, Co. Dublin. Stomachs of 

 Ascidians, Co. Clare. Sea-weeds, Co. Galway. " Lame and Belfast 

 Bays, Cork Harbour," Wm, Smith. 



Genus YI. Tessella, Ehr. 



Pmstules stipitate, stipes short ; not filamentous ; diaphragms 

 apparently reaching not further than the middle of the yalve, alter- 

 nate, arched, and in opposite directions on the opposite sides of the 

 frustule ; external edges of the diaphragms slightly striate. 



Tessella interrupt a, (Ehr.) Marine. 



Diagnosis of the species same as that of the genus. Of the side 

 view of this species, I have never been able to obtain a satisfactory 

 observation. (PL 29, fig. 7.) 



Kiitz. Bac, p. 125, T. xviii., figs. 41, 2. This author states with 

 hesitation that there is no stipes in this species, as also does Ralfs, in 

 Pritch., p. 804, PI. vii., fig. 5. — Striatella interrupta, Grunow, Yer- 

 hand. der K.K. Zool. Bot. Gesel., Band xii., 1862, p. 427. It is lobe 

 noticed that this species cannot be confounded with Striatella inter- 

 rupta, as described and figured by Heiberg, De Danske Diat., p. 75, 

 T. v., fig. 15, and Eab. El. Eur., sect. 1, p. 307. 



Sea-weeds, Co. Galway. Sea-weeds, Co. Clare ; in both which 

 localities it occurs in company with Striatella unipunctata. 



Eamily YII. AMPHIPLEUEE^, Kutz. 



Erustules free ; lanceolate on side view, with median line and long 

 narrow end nodules, but without central nodule, and exhibiting a sub- 

 marginal keel at each side. 



Genus I. AurHiPLETTEA, Kiitz. 



The characters of this genus may be regarded as those of the- 

 family. It will be found that the structure of the frustules in 



