444 



occurs also in Lamlash Bay. Eupodiscus sculptus occurs twice or 

 three times the size of Professor Smith's figure, and Eupodiscus 

 Ralfsii occurs, in the Corallina material, of remarkable size and beauty, 

 and in great abundance. Discs of this fine species, from 0'005" to 

 0*007" in diameter, are frequent, and some even reach the diameter 

 of 008/' Orthosira marina (olim Melosira sulcata) is very abun- 

 dant in Lamlash Bay. Syndendrium Diadema, figured by Mr 

 Brightwell in his paper on Chsetoceros, is not rare in Lamlash 

 Bay. It has not, I believe, been yet described as a British species. 



II. As I anticipated, these materials have yielded almost every 

 one of the new forms of the Glenshira sand. 



I have recognised the following : — 



Navicula maxima, a and (i Cocconeis costata. 



„ angulosa, « and fi 



„ latissima. 



„ humerosa. 



„ clarata. 



„ incurvata. 



„ splendida. 



„ didyma y, costata. 



„ didyma ^ 



„ form OS a. 



„ rhombica. 

 Pinnularia Pandura, Breb. 



„ inflexa. 



„ longa. 



„ fortis. 

 Cocconeis distans. 



It is impossible to doubt, that the few remaining Glenshira ma- 

 rine forms will yet be found in the Clyde, perhaps even in these 

 dredgings ; if not, in others. 



III. Besides the above forms, all of which I had figured, there 

 had occurred in the Glenshira sand 7 or 8 forms, the study of which 

 I had postponed, either from want of good specimens, or from their 

 extreme scarcity in that deposit. By the help of the new ma- 

 terials, I have been enabled to clear up, and to establish as distinct 

 species, every one of these forms, most of which are very curious and 

 interesting. 



IV. Lastly, I have detected, in these materials, a very large num- 

 ber of new species. These I have arranged in the following groups. 



Group I. 

 Naviculoid Forms. 



Amphiprora recta. 



„ lepidoptera. 



„ minor. 



Amphora Arcus 



„ Grevilliana. 



„ obtusa. 



„ crassa. 



„ plicata. 



„ elegans. 



„ lineata. 



„ rectangularis. 

 Tryblionella constricta. 



„ apiculata. 



Campylodiscus simulans. 

 Synedra undulata. 



1. Navicula minor, n. sp. 



2. „ Cluthensis, u. sp. 



3. „ inconspicua, n. sp. 



4. „ brevis, n. sp. 



5. Navicula Claviculus, n. sp. 



6. „ Musea, n. sp. 



7. „ rectangulata, n. sp. 



8. „ nebulusa, n. sp. 



