so G. F. MATTHEW: ILLUSTRATIONS OF 



Additioual material i'rom the St. John group enables the writer to add the following 

 to the characters of this species, given iu the Bulletin above cited : — 



The shell was considerably attenuated toward the apex, and was septate in the apical 

 third ; some individuals had campanulate apertures. The dorsal face is usually convex, 

 and has a well-rounded, elliptical margin at the aperture. The cast of an operculum found 

 in the shale with this species has a deep crescent-shaped furrow behind the nucleus, and 

 two linear furrows in front of the nucleiis, diverging at an angle of about 130'. 



The sculpture of the surface helps to distinguish this species from the others. The 

 ventral side is marked by distinct but rather line, transverse strite ; there are no lines of 

 growth spaced at regular intervals, except toward the attenuated apex and the smaller 

 camerated part of the shell ; the sides of the ventral surface are striated with several inter- 

 ru^îted, longitudinal lines. Most individuals show a decided arching forward on the dorsal 

 surface of the faint undulatory lines of growth. 



Length, about 30 mm. Width, about *7 mm. The rate of tapering in this shell is about 

 1 in 5, for the adult, and about 1 in 3J for the young. 



Horizon and Locality. In the fine, dark shales of l.t- and \.d, at Porter's Brook, St. 

 Martin's, and in \.c, at Eatclifl''s stream, Simonds, St. John Co., N.B. 



Hyolithes (Camerotheca) gracilis, u. sp. (Plate VI. Figs. 2, 2«. and h) 



If certain slender apical portions of shells, found in the fine shales of \.d, belong to 

 this species, the form was that of an extremely elongated and transversely suboval cone, 

 attenviated toward the apex, and almost cylindrical toward the aperture. The shell was 

 septate in the apical third, and its walls were very thin. 



The dorsal surface was flattened and terminated at the aperture, in a moderately- 

 arched lip. The ventral surface was also somewhat flattened, and terminated in a slightly 

 arched margin. 



An operculum, differing from that of the preceding species, has been found in the 

 layers of the shale with this species, which presents the following characters : it is thin 

 and transversely oval, with a flatter curve on the A^eutral than on the dorsal side, and it is 

 about one half wider than long ; the nucleus is very close to the ventral side, and a well- 

 marked depression extends on each side from the nucleus to the lateral angles ; the space 

 in ffont of the nucleus is slightly and broadly elevated, and has no angular slopes. The 

 ventral .slope of the operculum is abruptly turned up, and the nucleus is broad but not 

 prominent. The surface of the operculum is marked on the inside by several engirdling 

 lines of growth, and -^^ery faint, radiating strire are discernible on some parts of the surface. 



From three to six somewhat distant septa may be counted in the narrow part of the 

 tube of this species ; they are sometimes very distinct, but are often to be seen only as 

 faint, transverse ridges across the flattened surface of the shell. 



Sculpture. The ventral surface of this species presents, at the smaller end of the tiibe, 

 distinct annulations of growth, regularly spaced, and rather close together ; in some shells 

 this surface appears otherwise to be smooth, but in others a strong lens brings to view very 

 fine transverse strite. The dorsal surface exhibits faint, arched stria? and undulations of 

 growth. 



The surface-markings of one side of the shell of this species, as preserved in the shales, 



