30 JOHAN KIÆR M.-N. Kl. 



previously described species. Although practically speaking we have 

 nothing of these forms beyond cranidium without free cheeks, the study 

 of them has nevertheless proved interesting in several respects. Therefore, 

 after describing the forms found, 1 propose to discuss the development 

 and family relationship of this group of forms. 



It is usually the custom to refer to Matthew's family Ellipsocephalidae 

 two genera that have long been well known, viz., Agraulos Corda^ and 

 Ellipsocephalus Zenker, and also Matthew's newer family Stremiclla, which 

 is closely related to Ellipsocephalus. The legitimacy and limitations of this 

 family will be dealt with later on. 



In our Holmia shales, as in the Lower Cambrian of Scandinavia 

 generally, we find only two of these genera, viz., Strenuella Matthew 

 and Ellipsocephalus Zenker, the genus Agraulos Corda according to my 

 classification, appearing to comprise Middle Cambrian forms only. 



Strenuella Matthf.w. 



In the year 1886, Matthew- classified Strenuella as a sub-genus of 

 Agraulos Corda. The type is Strenuella strenua Billings, one of the most 

 characteristic forms of the Callavia fauna of Newfoundland. Later on both 

 Grabau and Shimer-^ and Raymond^ regarded Strenuella as an independent 

 genus, with which view 1 agree. 



According to Matthew, Strenuella difters from the real Agraulos 

 genus (type A. ceticephalus Bar.) by the following characteristics. "In the 

 marked elevation of the parts of the head shield, the long eyelobes and 

 the depressed anterior limb of the cheeks it resembles Ellipsocephalus ; 

 in the short and direct posterior extension of the facial suture it also 

 resembles this genus; the prominent glabella with depressed area behind 

 the anterior margin of the head shield are points of resemblance to Lio- 

 stracus." The most important of the characteristics thus emphasized are 

 the large, posteriorally situated palpebral lobes, that commence at the marginal 

 lurrow with its somewhat extended exterior, and the unusually short posterior 

 extension of the facial suture. In contrast to this, the real genus Ag?'auhs 



1 Like J. F. Pompeckj I have adopted Corda's old name Agraulos. instead of Arioiiellus. 

 (Fauna d. Cambrium von Tejrovic und .Skrej in Böhmen — Jahrb. K. K. geol. Reichs- 

 anstalt Bd. 45, 1895, pag. 548). 



2- On Cambrian faunas of Cape Breton and Newfoundland. (Trans. Roy. Soc. Canada, 

 Vol. IV, 1886, Cect. IV, page 153). 



3 North Ameiican Index of Fossils, Vol. II, 1910, page 278. 



* Raymond in Ch. R. Eastman, Textbook of Pal. Vol. I, 1913, page 717. 



