The post-oral plate is about 0°76 inch in length, and 055 
inch in breadth, the widest part being very slightly behind the — 
middle. Its general form is subovate. From near, or a li 
behind the middle, it rounds off rather rapidly to the rounded — 
posterior end, and tapers more ogerag! to the anterior ex-_ 
tremity, which is rounded on each side, and rather distinctly 
emarginate in the middle. The maxillary joints or plates ot 
the swimming feet expose a subtrigonal outline—their length — 
being 0°85 inch, and their breadth at the posterior margin — 
about 0°70 inch. Their lateral slopes are slightly sinuous 
along the middle, while their anterior ends (or the portions 
exposed) are very narrow, pointed, curved inward, and extend — 
scarcely beyond the anterior end of the post-oral plate. The 
succeeding joints are visible, but scarcely in a condition to be 
described. | 
20 Meek and Worthen on a Scorpion and other fossils 
The thorax measures 2°45 inches in breadth near the middle, - 
and a little more than 2 inches in length. Its middle seg- 
ments (on the ventral side) are 0°35 inch in length or anterio- 
posterior diameter, while the anterior and posterior ones, es-— 
pecially the latter, are shorter ; and they are all rounded on 
their posterior lateral angles. Some impressions in the matrix, 
however, show that the lateral terminations of the dorsal por- 
tion of the posterior thoracic segments or rings extended out — 
strong angular processes, nearly straigh : ch a 
oblique axterior io y straight behind, but wi | 
y 6 h not more» 
than half the breadth (more properly length) of the “er ge which 
he body se, 
in E. remipes, and other Silurian species, resemble body segments 
so closely that they were actually mi , y 
and second segments of the ate = Peleon by Prof. Hall, for 
2), and not suspected by him to 
ot aga bod gouns Lewis This error has been pointed out and corre 
: X , In his memoir on the genus Pter A j the Pa- 
leontographical Society, pp, 40 and 41-1866. ygotus, published by 
4 
