516 PROFESSOR GREGORY ON 



margin. Valves transversely striated. Striae about 24 in 0-001", conspicuous. 

 The portion of the valve outside of the curve line seems to be in a plane different 

 from that of the inner portions, and the striae on the latter are radiate. 



This well-marked and conspicuous species, remarkable for the position of the 

 central nodules, is by no means rare in one of the Loch Fine dredgings, in which, 

 except this form, Campy lodiscus angidaris, and C. Ealfsii, but few forms are found. 

 It occurs more sparingly in some of the other dredgings. 



79. Amphora robusta, n. sp. PL XIIL, figs. 79, 79 b, and 79 c. Form of frustule 

 a broad oval with subtruncate extremities. Length from 0*0033" to 0-0048", occa- 

 sionally even as much as 0*006. Breadth from 00018" to 00024". Valves arcuate, 

 with the ends more or less obtuse ; ventral margin straight or slightly concave. 

 Inner curve lines very sharp and strong, rise from the inner angles, pass outwards, 

 without reaching the outer margin, and bend suddenly inwards to the central 

 nodules, which are within the ventral margin, by one-fifth of the width of the valve. 

 In some specimens, or perhaps in a certain focus, the points where the two curve 

 lines meet in the middle is on the inner side of a straight line, apparently forming 

 the inner margin of the valve, so that a small blank triangular space is included 

 between that straight line and the ends of the two curve lines. This produces a 

 very peculiar aspect. Frustule thick, marked with strong striae, which on the 

 compartments outside the curve lines are transverse, but on the inner terminal 

 compartments are somewhat radiate. Striae subdistant, moniliform, about 16 in 

 0*001". Figs. 79 b, and 79 c, represent two valves, in one of which the curve lines 

 are seen, while it is evident that the inner compartments are in a different plane 

 from the outer one. The other shows the entire valve vieAved in a different focus, 

 in which the striae appear all in one plane. 



This fine form, conspicuous for its size and the stoutness of its aspect, is not 

 rare in the Loch Fine dredging mentioned under A . turgida, and occurs also in 

 Lamlash Bay. 



80. Amphora spectabilis, n. sp. PL XIIL, figs. 80, 80 b, and 80 c. Form nearly 

 rectangular, broad, with rounded angles ; occasionally sub-elliptic. Length from 

 0*003" to 00047" ; breadth from 0*002" to 0*0025". The inner curve lines bend in- 

 wards from the outer margin very nearly to the inner margin of the valve, divid- 

 ing the valve into a middle outer compartment, and two terminal inner ones. The 

 detached valve has prominent obtuse rostra or beaks, not seen in the entire form. 

 Outer compartment transversely striated, the striation being very coarse ; inner 

 compartments marked with radiate stria?, which are much finer. Aspect of the 

 whole form soft and indistinct, so that in general only the marginal ends of the 

 striae in the outer compartments are easily seen, these striae being thicker at that 

 end, and the frustule very convex. Even at the margin they are not sharp but 

 softened. Striae in the outer compartment 14 to 16 in 0*001" : in the inner ones, 

 26 in 0*001", and very obscure. As in the last species, and indeed in many Am- 



