184 NEW YORK STATE MUSEUM 
contraction and imperfect preservation. Inthe hypotype the dimensions of 
the preabdomen are 42x 63mm. The postabdomen of the type is 5o mm 
wide at the proximal end, 56 mm long and 17 mm wide at the distal end. 
That of the other specimen is too long by distention, its proximal width 
being 50 mm, its distal 17.5 mm and its length 73 mm (probable normal 
length about 65 mm). The telson of the type is 53 mm long and 1o mm 
wide at its proximal end. | 
Horizon and localities. The two known specimens are from the 
Bertie waterlime of the neighborhood of Buffalo. 
Eurypterus maria Clarke 
Plates 21, 22 
Eurypterus maria Clarke. N. Y. State Mus. Bul. 107. 1907. p. 305, pl. 1, 
fig. 1, 2, 4; pl. 2, fig. 2, 4, 7; pl. 3, fig. 1-5, 7 
The preliminary description of this form in Bulletin 107 is as follows: 
The general form of the largest observed individuals of this species 
is elongate and slender with very little abdominal expansion and no loba- 
tion of the segments. In these ephebic conditions the head 1s somewhat 
elongate, regularly rounded in front and with subparallel lateral margins. 
The eyes are crescentic, subcentral, as far asunder as the inner margin of 
each is from the margin of the shield. 
The ocellar lobe is well defined at an early stage. A specimen 63 
mm long without the telson, apparently mature, has 11 segments, but a 
break across the body leaves room enough fora 12th. The width of the 
base of the head is 15 mm and this is but very slightly less than the greatest 
expansion of the abdomen. Little trace of surface sculpture 1s visible on 
any of the parts. | 
Description. ody. The body is terete or subconical, with subcircular 
sections in all parts save the carapace. It 1s about five times as long as 
wide, and tapers very gradually from the base of the carapace. 
Cephalothorax. The cephalothorax is broadly semielliptic to semi- 
circular in outline, about one third wider than long, widest at the base 
and evenly rounded. While it is as broad as, or broader than, the widest 
part of the abdomen, it attains but one sixth to one seventh the length 
