514 PROFESSOR GREGORY ON 



distinguish it from that species, in which the striae are conspicuous and moni- 

 liform. 



This species is not unfrequent in the Loch Fine dredging mentioned under A . 

 turgida. It has some resemblance, in the form of the valves, to A. incurva, Greg, 

 figured in my first paper on the Glenshira Sand (See Mic. Jour., vol. iii., pi. iv. 

 fig. 5). But in A. incurva the striation is conspicuous, not hyaline, and the form 

 of the valve is more elongated, and less projecting at the extremities. I am not 

 yet acquainted with the entire frustule of A . incurva. 



74. Amphora Icevis, n. sp. PL XII., figs. 74, 74 b, and 74 c. Form of frustule 

 rectangular, slightly incurved in the middle, sometimes with the ends rounded, 

 but more commonly with nearly square ends. Length from 00017'' to 0-003"; 

 breadth from 0-0007" to 00012". Aspect very hyaline. In each valve the inner 

 curve line, rising from the inner angle of the valve, and following the margin out- 

 wards, bends inwards again in a long graceful curve to the central nodule placed 

 just within the ventral margin. The nodule extends as a strong bar across the 

 middle of the valve. The outer compartments are transversely striated, but the 

 stria? are very fine, about 60 in 001 ", very hyaline, and hardly to be seen with a 

 power of 400. 



I have added, in fig. 74 d, the figure of a fine Amphora, which probably be- 

 longs to this species. It is remarkable for the fact, that the curve line coincides 

 with the outer margin till very near the middle, where it bends inwards to the 

 nodule. There are also four longitudinal lines at considerable and equal distances. 

 In this specimen, I have not seen the striae as in the others ; but believing it to 

 be of the same species, I give the figure under the head A. lams. 



This species occurs with the last, and is more frequent, though by no means 

 abundant. It frequently happens, as in one of the figures, that the valves are in 

 apposition; and as this occurs in long examples, these become proportionally 

 narrow. 



75. Amphora exigua, n. sp. PL XIII., fig. 75. Form linear-elliptic, narrow, 

 with somewhat obtuse ends. Length from 0-0015" to 0-0022" ; greatest breadth 

 about 000035". The valves are transversely striated, the striae being strongest 

 at the margin. Striae about 28 in 0-001". 



This little form occurs, scattered, both in Lamlash Bay and Loch Fine. In 

 size and form it approaches nearest to A. lineata (PL XII. fig. 70) ; but its mark- 

 ings are totally different. It has no striking characters, but I cannot refer it to 

 the same species with any of the small Amphorce I have here described. 



76. Amphora dubia, n. sp. PL XIII., fig. 76. Form of entire frustule oval, 

 flattened, or even a little incurved, on the sides. The valves are concave in the 

 middle of the ventral margin ; so that as they are in apposition, there is a longish 

 rhombic opening in the middle, between them. They also diverge a little at the 

 apices. Within each valve is a faint line 5 nearly parallel to the outer margin, 



