Z29O NEW YORK STATE MUSEUM 
reach their largest size on the frontal mound and cheeks and extend over 
the whole carapace, including the eye mounds, in uniform density. 
The abdomen is slender. It expands gradually to the fourth segment 
whence it contracts again as gradually to the long and slender postabdomen. 
The greatest width is probably about one fourth greater than that of the 
carapace. The preabdomen is longer by one third than the carapace, and 
the postabdomen is but little longer than the preabdomen. The tergités 
are short plates with nearly straight anterior and posterior margins, while 
the sternites exhibit strongly curved posterior margins, the middle being 
strongly concave and the postlateral angles well rounded and produced 
backward. Traces of a marginal line of tubercles on the tergites have 
been observed and it is possible that the whole surface was tuberculate. 
The telson has not been observed in position, but it is quite probable 
that a slender spine, found in association with these remains, belongs to this 
species since it fully corresponds to the form of the postabdomen. 
Appendages. The chelicerae and first pair of legs have not been 
seen. Of the second pair but four segments of the specimen could be ex- 
posed without destroying the following legs, and of the third pair also a 
portion of a fifth segment. These exposed portions show that the legs were 
long and slender, the third still somewhat surpassing the second in length; 
thus the second to fourth legs continuously increase in length backward. 
The fourth and fifth segments, and presumably the following ones, are 
furnished with a series of straight, slender paired spines, about 6-9 pairs on 
each segment. The fourth and fifth pairs of long legs were not of equal size, 
but the fourth shorter by one eighth. The latter, fully reflexed, would reach 
the last postabdominal segment and the fifth leg the telson. The coxae of 
these legs are not exposed; the first and second segments, however, are partly 
seen and can be recognized as consisting of short rings; the third is 
somewhat longer, while the fourth is the longest and broadest of 
all. It is two and one half times as long as the third. The sixth is 
again shorter by one third while the seventh and eighth are distinguished 
by again increasing in length and decreasing notably in width. The 
