278 NEW YORK STATE MUSEUM 



shelled lamellibranchs of the genera Halobia and Daonella and yet 

 there is no positive evidence that the beaks are not axial nor of 

 any specialized anterior part which can be construed as an auricle. 

 They are probably to be regarded as an aberrant strophomenoid, 

 slightly convexo-concave, but the character of the shells is so 

 peculiar as to prevent their admission to any of the recognized 

 brachiopod genera. The strongly ribbed surface bears from 20 

 to 25 narrow radial plications separated by broad flat sulci which 

 in old shells may show traces of intercalary ribs but the primary 

 ribs are all simple. These interspaces are crossed concentrically 

 by wavy inosculating elevated lines like the fine lines on many 

 crustacean carapaces. We should not venture to say that the 

 shells are of Siluric type for the comparison made by Billings is 

 only remote, but there is a certain similarity both in form and 

 sculpture to the species described by Hall and Clarke as O r t h i s 

 ? g 1 y p t a from the Niagaran dolomites of Milwaukee [see Pal. 

 N. Y. 1894. v. 8, pt 2, p. 359, pi. 84, fig. 8, 9] which has been 

 compared with O. 1 o v e n i Lindstrom from the Swedish Upper 

 Siluric. One of the specimens appears to have cardinal spines 

 near one extremity but this appearance is probably misleading as 

 the shell may have here suffered an injury which has distorted 

 growth. 



Lower Devonic. Grande Greve, P. Q. 



Hipparionyx minor nov. 



The recognized distinction between the genera Hipparionyx and 

 Orthothetes or Schuchertella lies chiefly in the orthoid form of 

 the former and its very short hinge line. In respect to this char- 

 acter the specimens before us are pronounced. The ventral valves, 

 small in comparison with those of H. proximus, have a short 

 and low cardinal area, but in the dorsal valves the hinge line is 

 apparently longer than correspondence with the opposite valve 

 requires and these valves convey the impression of a straight and 

 tolerably long line extending more than one half the width of the 

 shell. On examination of the inner surface of this valve it is 

 seen that this area is really short and confined to the apical part 

 of the valve while the extended extremities are a thin expansion of 

 the lateral parts of the valve which make a rather sharp turn at 

 the cardinal angles. There is other divergence in the shell away 

 from the type of Hipparionyx and toward that of Orthothetes as 

 represented by such shells as Streptorhynchus umbrae- 

 u 1 u m Schlotheim and its variant expressions. 



