[MATTHEW] STUDIES ON CAMBRIAN FAUNAS 73 



occur on layers of the flags of Div. 2 6, of the St. John group at St. John, 

 but the arrangement of the markings is quite similar- to these. 



HYOLITHES, EichwaW. 

 Hyolithes IIathewayi, n. sp. (PI. III., figs. 5a to d) 



A large slender conical species, having quite a thin test. As the 

 shell is flattened in the shale the exact form of the orifice is not known. 



The aperture has on the dorsal side a moderately arched lip, the 

 height of the lip being scarcely one-quarter of the width. On the ventral 

 side the aperture was emarginate at two points corresponding to the 

 boundaries of the middle area on that side. 



In the known portion of this shell there were three conditions of 

 structure ; in the middle area on the ventral side the abraded shell shows 

 close set parallel bars at the proximal end ; these bars were divided across 

 at intervals. In the second thii'd of the shell these bars are short and 

 broken by more frequent cross-lines giving an apparently cancellated 

 structure. In the upper third of the shell these longitudinal bars do not 

 appear, but the shell is indented by transverse growth-lines. 



The surface of the shell on the dorsal side was smoother, but marked 

 by distant undulations of growth, curved to correspond to the curved 

 aperture. 



The ventral side was divided into three longitudinal areas, of which 

 each lateral one was half of the width of the central one. 



The rate of tapering of this conical tube was about 1 to 4 ; apical 

 angle about 20°. 



Sculpture. — The dorsal side appears to be smooth and shining, but 

 with a lens the surface is seen to be crossed by very fine transverse and 

 longitudinal stria> ; there are also transverse grooves that are more distinct, 

 at intervals of 1 or 2 mm. apart. 



The ventral side is marked by growth-lines, narrow grooves about 1 

 mm. apart, but irregularly spaced ; and by faint striœ parallel to these 

 and only visible with a lens. In passing from the lateral edge of the 

 shell the growth-lines and accompanying stria?, run backward at a 

 moderate angle to the groove which divides this area from the middle 

 area of the shell ; here they arch forward, and then at the middle part 

 of the mid area are nearly transverse, crossing the median line of the 

 shell in a gentle arch. The lateral areas of the ventral side have a few 

 longitudinal grooves more distinct than those on the dorsal side. 



Size. — Length of the known portion of the tube, 50 mm. ; estimate of 

 entire length, 65 mm.; width of the aperture, 1(5 mm. 



Locality and horizon. — Upper part of the Protolenus Zone at 

 Manuel's, Conception Bay. 



