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On some New and Rare Diatomacem from the Wrst 
Coast oF IrELanD. By Rev. Evucenr O’Mzara, A.M., 
Rector of Newcastle Lyons, Hazlehatch. 
THE matter supplied to me, of which only a small portion 
has as yet been searched, was raised in August last, as Dr. E. 
Perceval Wright informed me, from depths varying from ten 
to thirty fathoms, off the Islands of Arran, in Galway Bay. 
Taking into account the number and rarity of the species 
found in it, this gathering may be regarded as one of the most 
interesting ever made, certainly the most interesting ever made 
in Ireland. 
Some of the common marine species are met with ; for in- 
stance— 
Actinoptychus undulatus. Navicula didyma. 
Amphitetras antediluviana  Nitzchia plana. 
var. (3. in, Riga, 
Biddulphia aurita. Pleurosigma decorum. 
Coscinodiscus radiatus. ss formosum. 
minor. r quadratum. 
Campylodiscus Ralfsii. 7 strigosum. 
Eupodiscus crassus. 
Grammatophora marina. 
Rhabdonema arcuatum. 
Stauroneis pulchella. 
- serpentina. Suacwar: Ds 
ss maculata. Synedra Gallionii. 
Isthmia enervis. Tryblionella marginaia. 
It is a remarkable fact that the above-named species are 
relatively few, and the forms belonging to them, generally 
speaking, are not of frequent occurrence. 
Besides the common forms just enumerated, I have found 
a large number of the rarer species described by Donkin, 
Gregory, Greville, and Roper, investigators in this depart- 
ment of natural science whose discoveries have been made 
known since the publication of Smyth’s ‘ Synopsis of British 
Diotamacee,’ namely— 
Amphiprora maxima, Greg. 
Amphora sulcata, Roper. 
» robusta, Greg. 
» obtusa, Greg. 
s»  a@renaria, Donkin. 
Cocconeis pinnata, Greg. 
35 pseudomarginata, Greg. 
3 Grantiana, Grev. 
> scutellum, var. 3, Roper. 
VOL. VII.—NEW SER. H 
