THE 



GJilO LOGICAL MAGAZINE 



NEW SERIES. DECADE VI. VOL. V. 



Ifo. II.— FEBRUARY, 1918. 



OlRXG-XJSr .A.JL. -A-I?.tioil.e:s. 



I. — EocrsTis, I. EocYSTiTES PRiM^vus Hartt. 



By F. A. Bathee, M.A., D.Sc, F.R.S. 



(PLATE V.) 



(Published by permission of the Trustees of the British Museum.) 



ri'lIIE second edition of J. W. Dawson's Acadian Geology (1868) 

 X contains some notes communicated by C. F. Hartt. One of 

 these, on p. 643, runs as follows: — 



" Eocystites primceviis, Billings, Coll. Hartt (Fig. 220). The little 

 plate with radiating sculpture, represented somewhat enlarged in 

 the figure, is regarded by Mr. Billings, to whom the specimens have 

 been submitted, as indicating anew genus of Cystideans." 



In this perfunctory manner, without diagnosis or description, was 

 the genus Eocystites founded. Since a named species was mentioned, 

 that s])ecies, E. priniisvus, must be taken as genotype, and the generic 

 name is thereby validated. 



Eocystites primcevus again depends solely on tlie accompanying figure 

 220 (our Plate V, Fig. 1). Slight though this may appear, it does 

 represent a plate of peculiar and recognizable shape. The holotype, 

 which was said to be in Hartt's collection, was one of a series of 

 specimens from the " Primordial Group " of St. John, New Brunswick, 

 a group since referred to the Lower Cambrian. The specific name 

 therefore may be accepted, and unless the plate can be shown to 

 belong to some previously described genus and species, we must 

 regard Eocystites primcevus as representing an actual independent 

 zoological entity. 



It so happens that Dr. G. F. Matthew, of St. John, New Brunswick, 

 formed the opinion that the plates known as Eocystites pritncevus 

 were more properlj^ referable to Trochocystis. He did not publish 

 a definite statement to that effect, but he twice suggested or recorded 

 tlie existence of Trochocystis in Canada, namely, in 1896, "Faunas of 

 the Paradoxides-'^e^s in Eastern IS". America " (Trans. New York 

 Acad. Sci., xv, p. 207), and in 1899, " The Cambrian System in the 

 Kennebecasis Valley" (Trans. Hoy. Soc. Canada, ser. ii, vol. iv, 

 sect. 4, p. 128). This latter refers to "a single discoid plate" in 

 Division I b of the Cambrian at Long Island, Kennebecasis Bay, 

 Nova Scotia. 



DECADE VI. — VOL. V. — NO. II. 4 



