PLATE 
1. Pleurosigma angulatum 
WSm. 
2. Pleurosigma Aestuarii 
WSm. 
Pleurosigma quadratum 
WSm. 
Pleurosigma 
WsSm. 
Pleurosigma_ strigosum 
WSm. 
. PleurosigmarigidumW Sm 
,, affine var Normanii 
Si ,, Nicobaricum Grun 
delicatulum 
Q. ,, lanceolatum Donk 
10. ,, intermedium WSm 
rite - ay var 
nubecula. 
We ,, elongatum WSm. 
nee ,, acutum Norm. 
14. ,, decorum WSm. 
DG. ,, Hippocampus 
WSm. 
16. Pleurosigma attenuatum 
WSm. 
Notre.—The Diagram on the right of 
striae in 1 #4 (0.01 mm). 
a 
ish MU Se 
IQ. 
17. Pleurosigma attenuatum 
~ var scalprum (Gaill) 
Grun. 
18. Pleurosigma litorale WSm 
19. ,, Balticum WSm. 
20. af ,, var Brebi- 
ssonii. 
21. Pleurosigma acuminatum 
(Kutz) Grun. 
22. Pleurosigma strigilis WSm 
23. = Spencerii var 
Smithii Grun. 
24. ,, tenuissimum WSm 
25 ,, Parkerii. Harr. 
26. ,, distortum WSm. 
Nile ,, Fasciola WSm. 
28. na a var 
prolongatum. 
29.7 Pleurosigma tenuissimum 
var hyperborea Grun. 
30. Pleurosigma eximium 
(Thw) VH. 
31. Toxonidea insignis Donk. 
Ba) Ra undulata Norm. 
each figure indicates the number of 
