134 BRITISH FOSSIL CRUSTACEA. 



examine and figure the fine head of Earypterus Scouleri, which forms the subject of our 

 PI. XXVII. This is the original specimen figured in ' Cheek's Edinburgh Journal,' by 

 Dr. John Scouler, F.L.S., in June, 1831, under the name of MdotJtea. 



For the opportunity to figure the other carapace and conjoined posterior body- 

 segments of this remarkable Crustacean, forming the subjects of Pis. XXV and XXVI of 

 this Monograph (and which were with the preceding specimen all figured by Dr. Hibbert 

 in the 'Trans. Roy. Soc. Edinburgh,' 1836, vol. xiii, pi. 12), I am indebted to the 

 kindness of my friend James Powrie, Esq., F.G.S., of Reswallie, Forfarshire. 



Of the first of these specimens Mr. Salter writes as follows : l — " The large carapace is 

 all but perfect (a portion of the right side only being absent), and in its natural condition 

 uncompressed ; so that the great convexity of the form is manifest. The carapace and 

 the two front body-rings (preserved so as to show both their dorsal and ventral surfaces) 

 are retained in this specimen, attached to one another ; and, bent upward beneath it, is a 

 large fragment of a swimming-foot, consisting of the first four joints, all imperfect. 



" The dimensions are as follows : — Carapace, forming more than a quarter of a sphere, 

 [6] 2 inches long by fully [8] broad, and the convexity such as to follow the shape of the 

 body-rings, which are each [6^ inches] broad and [f inch] deep from back to front. The 

 greatest convexity is in the region behind the eyes, which are placed, not quite halfway 

 up the head, near together, only an inch and a quarter apart. They are divided from 

 each other by a pair of inflated triangular lobes, with a small central process lying in the 

 deep hollow between them. This central prominence, the round approximate eyes, 

 together with the rough, hirsute, spinous character of the convex region behind the eyes, 

 give the whole head much the appearance of a deformed human countenance. 



" The outline of the carapace is about two thirds of a circle, the short, broad, spinous 

 ears being curved inwards, not outwards ; and the posterior edge is only gently arched. 

 A very distinct depression indents the front, but does not affect the actual anterior 

 margin. The round prominent eyes are also set in depressions, which run from them in 

 a curved line to the inner margin of the broad posterior spines on each side, and thus 

 enclose the convex, semicircular space which, lying behind the region of the eyes, is 

 covered with thick-set spinous squamse. Another deep triangular indentation lies 

 between two thick lobes, diverging backward, which separate the eyes ; and, as these 

 lobes are much swollen, the depression is really greater than any of the others. In the 

 midst of it lies a short, triangular, prominent mass, broken in our specimen. Above, in 

 front of this depression, is a slight boss (which would very probably be the place of the 

 minute stemmata, were they preserved) ; but there are no wrinkles nor elevations of any kind 

 in front of the eyes. The whole surface is evenly convex, divided by the semicircular furrows 

 from the rugose portion behind the eyes, as above mentioned. The margin is narrow, 



1 'Quart. Journ. Geol. Soc.,' 1863, vol. xix, p. 82. 



2 The specimen having been remeasured, the numerals within the brackets are the correct dimensions. 

 — H. W. 



