4Js \KW YORK STATE MUSEUM 



McCoy 1. A comparison of tlie description and figure with our 

 spcecinieu shows a ( losi.' «iniihirity in the two fi^rnus, the limb 

 in both beinji appiuvntly alike, even to the breaking up of the 

 radial rowfl into iiTegular arrangement at the lateral angles. The 

 principal diiTerence between the two species seems to lie in the 

 shape of the glabella, which in the Trenton form is highly con- 

 vex, with a hemispheric frontal part and an abrupt contraction 

 U* a narrow ridge behind the same, as in T . reticulata. 



The posterior part of the glabella and cheeks are not so well 

 preserved as indicated by the drawing. 



AMPYX Dalman 

 Subgenus lonchodomas Augelin 

 Ampyx (Lonchodomas) hastatus sp. nov. 

 VI 3, tig. 1-10, 30 

 The black compact limestone pebbles contain in great abun- 

 dance cranidia and pygidia of a new species of Ampyx in 

 association with such Trenton fossils asPterygometopus 

 c a 1 1 i c e p h a 1 u s . 



Diagnosis. Cranklium hastate in appearance, terminal points 

 of glabella and fixed cheeks falling approximately into the angles 

 of a regular triangle. Glabella subrhombic, contracted ante- 

 riorly and posterioi-ly, most convex and widest near the middle; 

 more than half of it projecting snoutlike from the remainder of 

 the cranidium; carina (or in others only a flattened area) extend- 

 ing the whole length of the glabella. Two long elliptic depres- 

 sions, beginning in the pits at the base of the glabella, directly 

 in front of the neck furrow, extend at the foot of either slope 

 of the glabella for about one fourth of its length; two othei-s 

 directed obliquely downward, lie at the anterior ends of the 

 dorsal furrows at ilir point where glabella and fixed cheeks meet 

 exteriorly; two more lie directly above the others and are par- 

 allel to the axis of the glabella. On casts of the glabella (pi. 3 

 fig. Ti two prominent, transversely elliptic elevations can be 

 noticed directlv in fi(.iii of the neck ring. On the crust they 



vf oiRUKir ..f Milt pal, foss. 1855. pi. 1 E, flg. 16. 



