626 
Proceedings of Royal Society of Edinburgh. [sess. 
r Adjacent to border a distinct zone of large areolse, 
with inner edge wanting, and outer convex 
outwards, ....... 
42. ■{ Adjacent to border a single zone of still larger 
areolse, perfect, with inner and outer edges 
convex, ........ 
I No such zone, 
r Outer portion of valve scarcely siliceous from 3 
to \ of radius broad, with distant subuniform 
costse, 
Four subgelatinous, cuneate, symmetrical pro- 
tuberances. A distinct band adjacent to 
border ; within this markings in oblique rows 
2|, upon it 6, in '01 111m. , and in radial rows, 
149. -{ Markings round, robust, pearly, smooth, decreas- 
ing rapidly at border; at centre 2, at border 4, 
in '01 mm. Border sharp, of 1 to 2 bands of 
round granules, 
Markings angular, 10 in '01 mm. A narrow 
hyaline band adjacent to border. Apiculi 
j many, outer ends obtuse, . 
I No such outer portion or markings, . 
f Inner § of border hyaline between distant radial 
lines, outer ^ with 8 to 10 strise in '01 inm., . 
Border prominent, hoop-like, strise 1| in '01 mm. 
Markings 1| in '01 mm., a few more minute 
150. -J at wide intervals ; papillae obscure, 
Border subopaque, prominent, with coarse striae. 
Markings 2 to 2b in '01 mm., radial rows 
inconspicuous, ...... 
(.Border otherwise, ...... 
151. 
A single large apiculus near border, outside it a 
circlet of more minute ones. Markings on a 
narrow zone adjacent to border, granular, 
No such isolated large apiculus, 
{ Surface convex towards centre. Markings 
towards centre 4 to 4J, towards border 3, in 
I '01 mm., ....... 
152. \ Surface convex; markings at centre 2, at bor- 
‘ der 3, in '01 mm. ; at border a single band of 
quadrate, equal areolse, . ’ 
l Surface almost or quite flat, .... 
( Markings hexagonal, 2 in '01 mm. ; at intervals 
I more minute, more distinct areolse. A distinct 
| band of larger areolse adjacent to border, 
\^No interspersed minute areolse, .... 
( Markings hexagonal, 2^ to 3 in '01 mm. Apiculi 
154.4 clavate at inner edge of hyaline border, . 
No such apiculi, 
( Markings 1 J, decreasing outwards to 2 in '01 mm. ; 
, - _ I a ring of very large areolse adjacent to border. 
‘ 1 Non-apiculate, 
V No such distinct ring, . 
zonulatus. 
heteromorphus. 
149. 
sol. 
bipartitus. 
vigilans. 
cristatus. 
150. 
circumdatus. 
aphrastos. 
concavus. 
151. 
leptopus. 
152. 
tumzdus. 
Molleri. 
153. 
pulchelbjis. 
154. 
macraeanus. 
155. 
splendidus . 
156. 
