KONGL. SV. VET. AKADEMIENS HANDLINGAR. HAND. 34. N:o 8. 11 



meter of L,2 inni. is mi the top of a little mound and surrounded bj a fine, elevated 

 marginal line (Hg. 23). Its soinewhat convex surface is entirelj smooth and il sectioned 

 liorizontally exhibits the same sorl of spong) texture as A. expansus (pl. I I. 2 1). In ;i 

 vertical section (fig. 25) the macula does nol oocupy so large a space as in As. ex- 

 pansus, hut rather lies as a Lenticular disk in the hypostomic tesi doser t.) the superior 

 surface than the interiör. With suflicientk high power the same surt of pillars, divided 

 hy horizontal strata is seen. Upon the whole the vertical section is not so clearly 

 developed. The reticulate zone of the eye is more dehnitely separated from the prismatic 

 zone than in A. expansus. There can be no doubl that there is a correspondance in this 

 species between the structure of the maculee and the spongious zone of the eyes. 



Asaphus cornigerus Schloth. (A. Kowalewskyi Lawrow). 



Of this stränge 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 maculae, obovate-circular, are like those of several other Esthonian 

 species oriented inwards and upwards instead of inwards and downwards as in the Swedish 

 species deseribed. As the specimens have suffered through eorrosion of the surface there 

 are onlv faint traces of a marginal line. Their microscopic structure is badly preserved, 

 and the)- look påle and transparent with only few indications of the spongious texture. 

 The lenses of the cephalic eye are nearly square prisms sometimcs with a slight approach 

 to hexaedral pillars. There is no clear transition into a spongious <>r reticulate horder 

 zone. But this ma v depend upon the had preservation. 



Asaphus fallas Dalm.? 



IM. I Hg. 18—22. 



It is very difficull to distinguish this species or rather varietx from A. expansus, 

 hut if we have found genuine speeimens, there are some points in the shape of eyes and 

 niacuhe whieh 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 eyes are rather short, regular hexaedral prisms (f. 18 — 20) and as 

 shown in tig. 18 change into irregular squares near the horder of the eye. 



Asaphus sj). 



from Brunsby kanal, Segerstad parish, isle of Öland. The macuhc are large, påle whitish 

 and of an uncommonly fine-meshed reticulation, well limited from the surrounding 



hypostoma. 



