A MIDDLE CAMBEIAN FAUNA FKOM BENNETT ISLAND 17 



If the cranidium figured by Brogger (1. c.) is drawn true to nature, it does not seem 

 to belong to A. excavatum but to A. extornatum n. sp., hitherto confused with the former, 

 from which it is sharply distinguished, however. The two forms are very near related and 

 appear associated, at least in Scania; as regards the cephalon they differ mainly in the 

 curvature of the anterior branch of the facial suture (compare the description of A. sibe- 

 ricum). The pygidium figured by Brogger as A. excavatwm probably belongs here, though 

 its margin runs more angulately than is usually the case in this species. 



A. excavatum is common in the zone of Paradoxides forcJihammeri of Scandinavia. 



Anomocare sihericum n. sp. 



[PI. n, fig. 15—20; pi. Ill, fig. 1 (2?)] 

 1899 ? Bathyuriscus howeUi, v. Toll, Beitrage zurKenntniss des sibirisclien Cambriiun, p. 30, pi. 2, fig. 11. 



This species is closely related to the Scandinavian forms A. excavatum and A. extor- 

 natum n. sp. (pi. IV, fig. 22, 23), and in many respects it presents a great resemblance 

 also to A. limbatum (Ang.). Distinguishing characteristics are the following : iu A. sibericum 

 the palpebral lobes reach the axial furrows posteriorly, while in the Scandinavian forms 

 they do not. The occipital furrow in the former species is marked across the glabella, in the 

 last mentioned forms it is obliterated in the middle part of the glabella. The anterior branch 

 of the facial suture in A. sibericum runs about in the same maimer as in A. extornatum 

 and in A. limbatum, but in A. excavatum it is curved more strongly outwards. Consequently, 

 the width of the preglabellar field (between the anterior branches of the facial suture) is, 

 in the first three species, about twice the width of the glabella between the anterior corners 

 of the palpebral lobes, and in the last species about two and a half times this width. The 

 preglabellar field is markedly excavated in A. sibericum' as well as in A. excavatumi and 

 A. extornatum, in A. limbatum it is flat (or very faintly arched). ^ 



The pygidium of A. sibericum particularly resembles that of A. excavatum. It has 

 seven axial rings (including the terminal lobe) and five or six pairs of pleural furrows. The 

 axis occupies about one-sixth of the total width. In A. excavatumi the axis has five (or six) 

 rings and occupies about one-fourth of the total width; pleural furrows four (or five). From 

 the pygidium of A. extornatum, which is supposed to be the one referred to Anomocare 

 laeve Ang. by Gronwall (1902, p. 141) and Walcott,^ the Siberian form is readily dis- 

 tinguished by its entire margin and the ribs being more slightly curved backwards. A. limba- 

 tum has a semicircular pygidium with narrower marginal limb and doublure, throughout 

 of a uniform width. 



A pygidium from Olenek in Siberia, described and depicted by v. Toll under the name 

 of Bathyiwisciis hoivelli, and here refigured (pi. Ill, fig. 2), was later identified by 

 Fr. Schmidt (1904, pp. 440 and 527) with A. excavatum,. However it seems to present 



1 Cambrian Geology and Paleontology, vol. 2, pi. 17, 

 fig. Ic. The pygidium, wbicb in my opinion belongs to 

 Anomocare laeve, is shown on pi. IV, fig. 18. In the cha- 

 racter of the test it agrees completely with the cephalon 

 of the said species. Several specimens of the pygidium 



have been found in the Andrarum limestone, most of 

 them associated with cranidia or free cheeks of A. laeve. 

 It fairly well resembles the pygidium of A. megalurus 

 (Dajees) and A. minus Dames. (Compare Walcott, 1913, 

 p. 192). 



3AH, XXI, 8 . 8 



