PALEONTOLOGIC CONTRIBUTIONS 



73 



In general aspect our species is comparable to certain types of 

 Loxonema, as L. murrayanum Salter ( Canadian Organic 

 Remains, decade i, p. 31, 1859), but aside from the fact that true 

 Loxonema may not occur below the Silurian, that genus typically 

 possesses a shallow apertural canal which is absent in our primitive 

 form. There is no trace of a slit in the aperture or of a slit-band 

 on the whorls. This excludes it from the Murchisonias to which 

 it bears some resemblance. The lobelike extension of the outer lip 

 is a peculiar character which, however, is not above suspicion since 

 only one specimen is available and this feature may be due to an 

 accident of preservation. A similar though less developed lobe is 

 figured by Barrande of the Devonian S c o'l i o s t o m a bohemi- 

 c um (Syst. Sil. de la Boh., v. 4, pt 1, pi. 60, fig. 31) and thickened 

 outer margins of the aperture are 



characteristic of the Volutidae, as '^-^ ., . 



Marginella, Mitra, Athleta etc. At 

 any rate, this little Cambrian gas- 

 tropod is not referable to any of the 

 genera, of the Ordovician, as far as 

 .we are aware. 



Diaphorostoma sp. 



A very large Diaphorostoma 

 occurs in the Bertie waterlime of 

 Litchfield, N. Y., in association 

 with Eurypterus r e m i p e s. Fig . 32 Diaphorostoma 



The material, however, is not suffi- sp . Fragment of volution. Bertie 

 cient for a specific diagnosis. waterlime, Litchfield,' N. Y. 



Hormotoma gregaria nov. 

 Plate 25, figures 3 and 4 



Description. Small, moderately slender shells, of five to eight 

 volutions. Apical angle rather wide. Volutions rounded, less con- 

 vex above than below, with a slight angulation. Sutures simple, 

 deep. Slit-band rarely observable on the exfoliated, compressed 

 specimens, rather wide, bounded by two fine raised lines. Growth- 

 lines fine, apparently slightly convex forward between suture 

 and slit-band and curving forward in a concave line below the 

 slit-band. Aperture rounded, about as wide as high, a little pro- 

 duced below. Inner lip not distinctly observed. 



Measurements. Length of shell 9 to 16 mm. Apical angle 

 about 23 °. 



