FAUNA OF THE ST. JOHN GEOUP. 



37 



Var. Norvegicum. Kjerulf ? 

 Dictyoneina Norvegicum, Kjerulf Veivi.ser, etc. I'l. ii, fig. 1. 



There is occasioually found in the middle and upper hiyers of the Dictyouema shale 

 a form which appears to correspond to this variety. 



Dr. Brogger describes the variety as having thick cross-threadi connecting the branches, 

 and also that the net-like iveb is close, producing smull. short, corner-like meshes} He further 

 says that while the cross-threads are thick, they are not nearly as thick as the branches of 

 the hydrosome. 



In our form which is referred doubtfully to this variety, the threads sometimes 

 appear nearly as thick as the branches, but usually they are considerably thinner; the 

 web is larger and more open than that of the Norwegian form. It probably runs into 

 the typical variety. 



To present in a synoptical form the chief features of these Acadian varieties of Dicty- 

 oneina flabeUif orme the writer has noted the principal distinctions in the following table. 

 In this the examples are arranged according to the form of the hydrosoma, and the length 

 and width are given in millimetres. The number of branches at the end of the hydro- 

 some and the number of cross-threads and of hydrothecse in the space of ten millimetres. 



" Die Silurischen Etagen," 2 und 3, p. 36. 



