CRUSTACEA. 
161 
spines of considerable strength. Impressions, which have apparently been 
left by the projecting spines of the anterior somite, are visible upon the 
anterior portion of the next one, caused by compression during the pro¬ 
cess of fossilization. There are eight spine bases upon the posterior somite, 
one of these being situated on the lateral margin, six upon the dorsal mar¬ 
gin, and one on the ventro-lateral margin, the ventral margins bearing 
none. 
The surface is covered with low, distant, scale-like pustules, undoubtedly 
less conspicuous and apparently more distant upon this internal cast than 
they were upon the external surface. 
Dimensions. The length of the entire fragment is 90 mm. The anterior 
somite measures 43 mm. in length and 60 mm. in width; the posterior 
44 mm. in length and 55 mm. in width. 
Observations. This remarkable fragment, which was regarded by the author 
of the species as of vegetable nature and referred to the genus Equisetides 
(Dawson, loc. cit.), exhibits undoubted crustacean characters. Attention was 
called to this fact in the following note appended to the explanatory text 
of plate 15 of the Thirty-fifth Report on the New York State Museum of 
Natural History; this plate being made up of several of Dr. Dawson’s figures 
of Devonian plants, and introduced in the report to illustrate an accompanying 
paper by Mr. Berlin H. Wright, on the geology of Yates county, N. Y. 
“Note (Fig. 1). —The peculiar aspect and markings of this figure, as originally published in the Quarterly 
Journal of the London Geological Society, led the writer to suspect its relations to the Crustacea. Through 
the kindness of Mi'. Wright, who procured the loan of the specimen, I have had an opportunity of seeing 
the original, which is very correctly represented in the figure. The body is not cylindi'ical, but broadly 
elliptical or sub-ovate, enlarging above. The ridges occur only upon one side, having a symmetrical relation 
with the form of the body, while the othei' parts are free ti-oni them, and the joints are overlapping. The 
form of this body, together with the character of the ridges and the finer surface markings, suggest its 
crustacean oi'igin. The lateral scars have probably been points of attachment fcir spiniform processes as in 
Styloniu'us. The fragment reiiresents two of the abdominal segments of a form not nnlike Stylonurus, though 
comparatively longer than in the ordinary forms of that g-enus, and in this resiiect resembling Slimonia.” 
After the recognition of its crustacean character, as expressed above, casts 
of the specimen and drawings of its finer markings were, at his request, sent 
to Dr. Henry Woodward, by whom, in association with Professor Jones {loc. cit.), 
