70 . Mr. T. H. Withers on 
Stramentum expansum, Withers, sp. 
haworthi, Williston, sp. 
levissimum, Zittel, sp. 
macadami, Wyville Thomson, sp. 
pulchellum, G. B. Sowerby, jun., sp. 
, G. B. Sowerby, sp., var. gigas, Fritsch. 
, G. B. Sowerby, sp., var. minor, Fritsch. 
syriacum, Dames, sp. 
tabulatum, W. N. Logan. 
— 
———= 
—_——: 
Without an examination of the specimens, it is impossible 
to deduce from the published descriptions and their inade- 
quate figures whether all of the above are distinct species 
and varieties. It has, however, been possible to examine 
the type-material of S. pulchellum and S. darwini, with the 
result that no justification appears for considering S. darwint 
to be distinct from S. pulchellum. ‘The distinctions given by 
Dr. H. Woodward are “ much greater size and more remark- 
able capitulum” and “the form of the scutum and the 
latera.” Apart from the fact that all the specimens came 
from the same-horizon and chalk-pit *, what differences are 
seen in the scutum appear due to the age and degree of 
development of the valve (see p. 73), and even the two 
specimens of ZL. darwini differ in this particular. No 
distinct differences are apparent to me in the latera, and if 
by “ more remarkable capitulum” Dr. Woodward means in 
the greater obliquity of the summit of the peduncle, it must 
be pointed out that this is accentuated in that particular 
specimen merely because the scutum and upper latera have 
been slightly displaced and pushed down on to the upper 
scales of the peduncle (see Pl. III. fig. 2). S. darwini is 
therefore regarded here as a synonym of S. pulchellum. 
With regard to the holotype of S. macadami, Prof. Gren- 
ville Cole very kindly took considerable trouble to find out 
for me its whereabouts, and recently informed me that it is 
preserved in the Belfast Public Art Gallery and Museum. 
The Curator, Mr. Deane, most kindly lent me the specimen, 
and an examination of it shows no characters by which it 
can be separated from S. pulchelium. Prof. Thomson stated 
in his description ‘‘ One specific distinction is very evident,— 
the fusion of plates corresponding to the scutum and the 
scutal latus in the upper rows of the peduncle.” I cannot 
understand this statement for the reason that none of the 
peduncular plates are fused, but, on the contrary, have pre- 
cisely the same structure as in the several specimens of 
* See G, E. Dibley, 1918, Proc. Geol. Assoc. vol. xxix. pp. 70, 87. 
