J916. No. 10. THE LOWER CAMBRIAN HOLMIA FAUNA. 37 



latter species by its broader frontal brim and a distinct furrow between 

 that and the glabella. Both forms, however, agree in these respects, and 

 also in the majority of the other proportions of the cranidium. The glabella 

 however, is comparatively longer and the cervical ring much shorter 

 (narrowerl. 



In other respects, as we have shown, baltica is distinguished by a 

 more considerable size and a flatter form, with on the whole less marked 

 features. We must also notice the disapperance of the glabella furrows, 

 all of which peculiarities may be regarded as due to the circumstance that 

 we are dealing with large and old specimens. The narrow cervical ring 

 and the somewhat longer and therefore comparatively narrower glabella 

 are factors that prevent me from definitely placing this form with the true 

 primaeva. 



T\\e Streyiuella form described byMoBERG^ from Tornetræsk as pn'maevus, 

 also does not agree entirely with the typical form from Temten. The 

 specimens were found in a gray clay shale (Beds No. 23 in profile II), 

 i. e. - a similar method of preservation. The dimensions there are also 

 greater, the length of the cranidium being about 15 mm. The specimen 

 most in conformity is that depicted in fig. i, this agreeing well with the 

 Norwegian specimens; the cervical ring, however, has a remarkable trian- 

 gular form, but it is conceivable that this is an exception. 



The forms of the cranidiums are less marked, which may possibly be 

 due to the fact that the specimen is large and old. The two other speci- 

 mens that are depicted differ more widely. In both cases the cranidium 

 is comparatively narrower than in the Norwegian form, the cervical ring 

 is not so long (broad), and the glabella is more rounded at the sides and 

 in front In this respect the form agrees with the large specimen from 

 Skaane. 



The only Swedish specimens which we may venture to identify — al- 

 though not without some hesitation — with the real primaeva Brøgger, 

 are therefore Lin.narsson's little specimen from Forsemölla and Moberg's 

 specimen fig. i from Tornetræsk. The others differ too widely. At the 

 same time both the above and Wiman's balticus are so near the Norwegian 

 form that they may be regarded as varieties of the latter. Moreover they 

 come from corresponding horizons. I will therefore here separate the 

 following forms : 



Strenuella primaeva Brøg. Forma typica. The typical foim from 

 Temten. 



1 Bidrag til kännedomen om de Kambriske lagren vid Torneträsk. 1908. 



