84 REPORT — 185G. 



yet been recorded as occurring in the Firth of Clyde. The new material was nothing 

 more than dirt washed from some nests of Lima hians, dredged by Prof. Allman off 

 Arsan, in four fathoms water, on the 19th of July. After washing wilh acids, &c., 

 a residue, rich in Diatoms, was left. In this the author found — 1. Many common 

 species, both freshwater and marine ; 2. Many known but rare or curious marine 

 forms, such as Navicula Hennedyi, Sm. ; Lyra, Ehr. ; granulata, Breb. ; Pleurosigma 

 transversale, Sm. ; obscurum, Sm. ; rigidum, Sm. ; delicatulum, Sm. ; Stauroneis 

 pulchella /3, Sm.= Stauroptera aspera, Ehr. ; Eupodiscus Ralfnii, Sm. ; crassus, Sm. ; 

 Coscinodisciis concinnus, Sm. ; Eupndiscus sculptus ; Podosira Montaguei, Sm. ; Cam- 

 pylodiscits Horologium, Sm. ; Surirella fastuosa, Sm. — 3. Many of the new forms 

 figured by the author in his two papers on the Glenshira Sand, the third part of 

 which will not be published till October. Those here found are Navicula rhumbica, 

 W. G. ; maxima, W. G. ; maxima, var. /3, W. G. ; quadrata, W. G. (Immerosa, Breb.); 

 latissima, W. G. ; angulosa, W. G. ; angulosa, var. &, W. G. formosa, W. G. ; 

 Pandura, Breb. ; Crahro, Ehr. ; incurvata, W. G. ; splendida, W. G. ; didyma y, 

 costata, W. G. ; didyma, W. G. ; clavatn, W. G. ; Amphora Arcus, W. G. ; Amphi- 

 prora vitrea /3, W. G. ; Tryblionella constricta, W. G. ; Synedra undulata,W . G. 

 {■=zToxarium undulatum, Bailey). The above are all correctly figured in the two plates 

 of Glenshira forms already published. The following are figured in the plate to be 

 published in October : — Cocconeis didaits, W. G. ; costata, W. G. ; Amphora crassa, 

 W. G. ; elegans, W. G. ; Grevilliana, W. G. ; Amphiprora minor, W. G. ; NUzschia. 

 insignis, W. G. ; socialis, W. G. ; distans, W. G. ; Eupodiscus sparsws, W. G. ; 

 Campylodiscus simulans, W. G. ; and another disc not yet named. It thus appears 

 that about thirty of the new marine forms of the Glenshira Sand occur in this ma- 

 terial, as might be anticipated from the connexion between Glenshira and Loch Fyne 

 which is an arm of the Firth of Chde. — 4. Many forms which appear to be entirely 

 new. These consist of — a. Navicuiae and Pinnularise, of which there are several, 

 chiefly small ; but there is one very fine large Navicula, of very peculiar aspect, which 

 proves to be N. proetexta, Ehr. It has a marginal and two medial striated bands, 

 and the space between these is irregularly powdered with round granules, the same 

 as those of which the striae are made up. One of the smaller forms exhibits, 

 at one focal distance, a striated marginal band, at another the whole valve is seen 

 to be striated. There are several others, which the author has not had time as 

 yet to study. 6. Filamentous forms, of which there are several. One is ap- 

 parently' a Denticula, a fine large form, which, as no marine species of the 

 genus are known in Britain, the author names, provisionally, Denticula marina. 

 Four appear to be species of Zygoceros, two of which are rather large, and two 

 smaller. One frequent form is that named by Smith, from the front view alone, 

 Himanlidium Williamsoni. The side view proves it to be not a Himantidium ; and it 

 is probably a Diadesmis. A predominant form in the material is a small disc, possi- 

 bly = Coscinodiscus minor, Sm. But it is here seen to be an Orthocira. c. Cocco- 

 neides. There appear to be three or four species of Cocconeis, which are only 

 mentioned, not having been fully studied. Two of these are allied to C. distans, 

 which also occurs as above stated, and is both frequent and fine, and, notwithstand- 

 ing the opinion of Prof. Smith, is held by the author to be entirely distinct from C. 

 Scutellum d. Discs. These are some apparently new discs, one of which is a large 

 Campylodiscus, allied to C RaJfsii, which the author has also found in the Glenshira 

 Sand, but has not yet described, e. Amphorae. Of this genus, of which the Glen- 

 shira Sand has yielded so many and such remarkable new species, this material, be- 

 sides several of the Glenshira forms, including two of the finest, A. crassa and A. Gre- 

 villiana, has yielded a large number of new, and in most cases very remarkable spe- 

 cies. One of these is nearly square, one is linear with an expansion in the middle, 

 and one is linear with two such expansions. There are probably about ten new spe- 

 cies of Amphora, but it has been impossible in so short a time to determine them 

 properly. Almost all the forms which have been named above, whether known or 

 undescribed, occur finely developed, and there are also very fine specimens of many 

 forms which have not been named. On the whole, the author trusts that this pre- 

 liminary notice will show how much remains to be done among marine Diatoms, and 

 how desirable it is that marine deposits on mud should be carefully and minutely 

 searched. 



