NEW FORMS OF MARINE DIATOMACE.E. 511 



run nearly parallel to the outer margin of the valve, but are less curved, and 

 generally obscure. Stride transverse, obscure, about 30 in 0-001". 



This very curious little form occurs by no means unfrequently in Professor All- 

 man's dredging from Lamlash Bay, and more sparingly in the Loch Fine dredg- 

 ing alluded to under A . turgida. The resemblance of the detached valves to Eu- 

 notia Camelus has been mentioned. The entire frustule also resembles amin i a- 

 ture of A. angidaris, Greg., figured by me in my first paper on the Glenshira Sand. 

 (See Micr. Jour., vol. iii., pi. iv., fig. 6.) But besides the much smaller size of 

 A. binodis, the expansions in A. angularis are more angular; indeed, the figure 

 represents them less so than they are ; and the striation of A. angularis is not 

 only distinct, but very much coarser, so that the whole aspect of the two forms 

 is different. 



68. Amphora ventricosa, n. sp. PI. XII., fig. 68 and 68 5. Form linear-lan- 

 ceolate, with obtuse apices, more or less expanded in the middle. Valves long, 

 very slender, arcuate, with acute ends, marked with somewhat coarse transverse 

 striae. Length from 0-0023" to 0-0035"; greatest breadth at the expansion in the 

 middle 0-005" to 0-008". Inner lines generally obscure, but in some cases well 

 seen. They arise from the inner angle of the valve, pass rapidly across, and, as 

 shown in fig. 68 b, sometimes extend beyond the outer margin ; then suddenly 

 bend inwards to meet the obscure nodule near the inner margin. Rectangular 

 middle space narrow. Striae strong, about 22 in 0-001" ; conspicuous. 



This pretty and interesting species occurs not unfrequently both in Professor 

 Allman's dredging from Lamlash Bay, and in the Loch Fine one so often alluded 

 to above. The detached valves resemble a very long and slender Cymbella, as 

 may be seen in fig. 68, in which the form of the valve is plainly seen on each 

 side of the frustule. By focussing, a transverse bar, or elongated nodule, may 

 be seen in the middle of the valve ; but it is obscured by the striae, when they 

 are in focus. 



69. Amphora monilifera, n. sp. PI. XII., fig. 69. Form elliptic, slightly re- 

 curved at the apices, which form very short produced extremities. The recurved 

 ends of the valves do not meet, and the space between them is filled up by a 

 transverse curve-line. Valves arcuate, very convex on dorsal margin, with re- 

 curved ends. Nodules on the ventral margin. Between the valves the frustule 

 is marked by three to five longitudinal rows of distant round granules, giving 

 to it a dotted aspect. If there be transverse striae, they are very obscure. Length 

 from 0-0017" to 0-0026"; breadth from 0-0008" to 0-0011". 



This pretty and well-marked species is tolerably frequent in the two dredg- 

 ings mentioned under the last form, but chiefly in that from Lamlash Bay. It 

 occurs also very sparingly in the Glenshira Sand, as may be seen by referring to 

 my last plate {Trans. Mic. Soc, vol. v., pi. i., fig. 53). I had figured, from that 

 deposit, an imperfect specimen, which at first I took for an Amphora, but subse- 



