426 NEW YORK STATE MUSEUM 
that the former has a “shorter carapace, comparatively wider body, 
longer and stronger telson and the eyes are more oblique and distant.’”’ All 
these are differences due to compression. The specimens of E. mans- 
fieldi are squeezed laterally, as shown by the longitudinal wrinkles, 
while those of the E. stylus are compressed longitudinally, as evinced 
by the transverse wrinkles [see Hall, pl. 5, fig. 15] and by the pushing 
together of the tergites. For the same reason the telson appears relatively 
longer in E. stylus thanin E. mansfieldi. The types of 
both species have all other characters in common, even to the remarkable 
sculpture and the anterior median process of the carapace. 
The frontal margin of the carapace. bears a peculiar small, trian- 
ee” gular lobe in the middle, which is well 
shown in the originals of Hall’s figures, 
plate 5, figure 3, 12 and 1s. In others it is 
broken out. In figure 12 it was clearly origi- 
nally drawn in, but later erased again [see also 
Mig 116,107 Bury pterus (Anthre our text fig, qa] and in his plate Git is etull 
PA es) ego Seas, ion 
a. 6 t See . . . . 
E. stylus refgured to sew the visible in outline. It is hollow, or spoonlike, 
frontal spine and outline aoe carapace. * 
Ty’ A'frontal spine’ Xs” ™ ™® on the upper side and has very strong walls. 
The sculpture is beautifully preserved in the specimens, is of striking 
character and not exaggerated in the drawings. The scales of the carapace 
are broad and roundish in the middle part between the lateral eyes and 
become more angular and protruding at their posterior points as they 
approach the base of the carapace giving that part a shagreened aspect. 
The same feature is still more emphasized on the tergites and postabdom- 
inal segments. On these the anterior half is ornamented with extremely 
small, crowded, broad scales, which abruptly are replaced by the posterior 
zone of large pointed scales and imbricating larger and smaller ones. In 
the middle line a number of scales unite and rise into nodes, the scales 
themselves thickening into bulblike bodies [see Hall, pl. 5, fig. 3; pl. 8, 
fig. 1 and our text fig. 44]. The character of the scales is entirely that 
of A. mazonensis, the type of the subgenus [see pl. 26, fig. 1] and 
