CRUSTACEA. 161 



spines of considerable strength, Empressions, which have apparently been 

 k'lt 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 eighl spine liases 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, Joe. 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 (Pig. 1 ). — The peculiar aspect an*d markings of this figure, as originally published in the Qi i 

 Journal of the London Geological Society, led the writer to suspect its relations to the Crustacea. Thro 

 the kindness of Mi-. Wright, who procured tie- loan of the specimen, I have hail an opportunity of seeing 

 the original, which is very correct!} represented in 'lie figure. The bodj is not cylindrical, but broadly 



elliptical or sub^ovate, enlarging above. The ridges occur only upon one side, having a sym trical relation 



with the form of tic body, while tie- other parts are fi from 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 origin. The lateral scars have probablj I n points of attachment for spiniform processes as in 



Btylonurus. The fragment represents two of the a In luminal segments of a form not a kt Stylonurus, thou 

 comparatively longer than in the ordinary forms of that genus, and in this respi nonia." 



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.), 



