56 JOHAN KIÆR. M.-N. Kl. 



segments without any enlargement of the third, and with a small, more or 

 less transverse pygidium with mereh' traces of segmentation on the axis^. 

 In addition to the geno-type Holmia Kjendfi Lnrs. he includes also Holniia 

 Lundgreni Moberg and Holmia Roivci Walcott. Finally in a later work, 

 he classifies although with some doubt, a fourth Holmia form, viz. Holmia.-^ 

 macer Walcott-. 



On closely examining these forms, however, we find that it is difficult 

 to refer them to the genus Holmia. 



Moberg's form Holmia Lundgreni, for instance, undoubtedly does not 

 belong to the genus under consideration. With its sword-shaped and bent 

 pleurae and by the build of the cranidium with its straight posterior edge 

 without intergenal spines and its broad genal spines, it belongs to a 

 distinctly different type. Both these and other structural features agree 

 with those of the new form from Tömtt-n which is described in the present 

 work, and for which I have formed the new genus Kjcndfia. 



The two other forms it is true, possess certain structural features that 

 more closely resemble those of Holmia Kjendfi Lnrs., but it is doubtful 

 whether they ought to be referred to the same genus. 



Holmia Roivei Walcott resembles the Geno-type in the form of 

 the cranidium, especially in the contours of the posterior edge, the strong 

 spines of the occipital segment, and the long, narrow genal spines. How- 

 ever, the intergenal spines appear to be entirely lacking; moreover, the 

 glabella is considerably narrower and less differentiated, and — a point of 

 especial importance — the marginal brim is narrow and runs sharply 

 marked along the whole anterior edge. This indicates uniform, narrow 

 hypostome attachments, to which the hypostome is only looseh' fastened. 

 The number of thoracic segments is given by Walcott as 16, but two 

 of his figures distinctly show 17 segments. (PI. 29, figs 3 — 4). They form 

 a uniform series as in H. Kjendfi Lnrs. but the form of the pleurae is 

 different, as are also the contours of the thoracic spines and the pygidium. 

 Finally, the sculpture of the shell is difterent. Holmia Rowei Walcott, 

 therefore, in spite of several points of resemblance, does not appear to be 

 very closely related to the Scandinavian form. This is also shown by the 

 quite distinct geological occurrences of the two forms. Holmia Roivei Wal- 

 cott is found in the oldest part of the huge west American Lower Cam- 

 brian series, Holmia Kjendfi Lnrs. in the upper part of the Lower Cam- 

 brian. 



^ Olenellus & Other Genera of Mesoiiacidae (Sjiithson Misc. Coll. Vol. 53, Num. 6, 19 10, 



page 247 & 287). 

 - New Lower Cambrian .Sub-Fauna iSmithson Misc. Coll. Vol. 57, No. II. 1913, page 3131. 



