512 PROFESSOR GREGORY ON 



quently supposed to be possibly not Diatomaceous. The Lamlash Bay dredging 

 soon cleared up this point, and established it as a distinct species of Amphora. 



(Since the preceding description was written, I have ascertained that this 

 species belongs to the complex group. Like the other complex species, it is formed 

 of a number of Cymbelloid segments, arranged like the segments of a melon, as 

 will be more particularly described farther on, in some of the other species. The 

 convergent longitudinal lines of dots prove to be the dotted backs of the central 

 segments. I have not been able to find a detached segment, the frustule being 

 usually entire, so that I cannot give a figure of the segment. I can see, however, 

 that it has the form of a Cymbella.) 



70. Amphora lineata, n. sp. PL XII., fig. 70. Form elliptic or elliptic-lanceo- 

 late, with short, produced apices, which are truncate. The valves are slender, 

 arcuate on the dorsal, straight on the ventral margin. The nodules lie in the 

 middle point of two strong lines, slightly curved, within the ventral margin. 

 Outside of the nodule is another curve-line, dividing the valve longitudi- 

 nally into two parts, the outer one being the broader. This outer portion is 

 marked by fine longitudinal lines, of which there are generally four in each 

 valve. The rectangular middle space is narrow, and has a sharp line down 

 the middle. This line, with the inner margins of the valves, the slightly curved 

 line with the nodule, the line beyond it, and the four exterior lines, give to the 

 whole a lineate aspect, which is very characteristic. In certain views, the frus- 

 tule appears lineate uniformly from one side to the other. Length from 0-0022" 

 to 0-003" ; breadth of frustule 0-0007" to 0-008". The whole frustule is marked 

 with transverse parallel striae, which are fine, about 42 in 0*001", and obscure, 

 except at the margins, where they may generally be distinctly seen. As the lon- 

 gitudinal lines, however, are much more conspicuous, it is they which charac- 

 terize the species. 



This species is not unfrequent in the dredgings so often mentioned, and occurs 

 also in the Glenshira Sand. In my last paper on that deposit, I described and 

 figured it {Trans. Mic. Soc, vol. v., pi. i., fig. 33). But by some mistake of 

 mine, the form there figured was either not a characteristic specimen, or, more 

 probably, a form of A. salina. I have therefore described it anew, and given, in 

 fig. 70, an accurate representation of a very frequent size and shape of this 

 species. 



71. Amphora Ergadensis* n. sp. PL XII., fig. 71. Form elliptic-lanceolate, 

 narrow, with truncate apices, which are very slightly expanded. Valves in ap- 

 position, or nearly so, long, slender ; the inner lines, on which lie the conspicuous 

 central nodules, forming one gentle curve from one end of each valve to the other. 

 Length about 00035'' ; breadth in the middle 0-00075". The valves are marked 

 by strong and conspicuous transverse striae, about 24 in 0-001". 



* 



From Ergadia, Argyll. 



