Of this strange species with its enormous eyestalks, more than 2 centimeters in length I have through the kindness of Akademiker Friedr. Schmidt in St. Petersburg had occasion to study some specimens.
The rather large maculæ, obovate-circular, are like those of several other Esthonian species oriented inwards and upwards instead of inwards and downwards as in the Swedish species described. As the specimens have suffered through corrosion of the surface there are only faint traces of a marginal line. Their microscopic structure is badly preserved, and they look pale and transparent with only few indications of the spongious texture. The lenses of the cephalic eye are nearly square prisms sometimes with a slight approach to hexaedral pillars. There is no clear transition into a spongious or reticulate border zone. But this may depend upon the bad preservation.
Asaphus fallax Dalm.?
It is very difficult to distinguish this species or rather variety from A. expansus, but if we have found genuine specimens, there are some points in the shape of eyes and maculæ which make it different. The hypostoma ([f. 21]) is rather more broad and the duplicature is large with an upturned margin. The little macula is placed on the top of a smooth rounded elevation and enclosed by an elevated rim.
The cephalic eves are rather short, regular hexaedral prisms ([f. 18-20]) and as shown in [fig. 18] change into irregular squares near the border of the eve.
Asaphus sp.
from Brunsby kanal, Segerstad parish, isle of Öland. The maculæ are large pale whitish and of an uncommonly fine-meshed reticulation, well limited from the surrounding hypostoma.
Asaphus sp.