Dr. H. Woodward — Cretaceous Canadian Crustacea. 397 



flattened concretionary nodule of soft argillite, with a small piece 

 broken off from one end, but enough of the matrix has been 

 removed to show most of the carapace and the upper surface of 

 a few of the abdominal segments. The anterior extremity of the 

 carapace, with the rostrum, is unfortunately not preserved, and the 

 tail, with some of the posterior abdominal segments, was broken off 

 when the nodule was found. The ambulatory feet are preserved, 

 but it was found to be scarcely possible to remove the soft shale 

 from around them without running the risk of spoiling the specimen. 



" The carapace, like that of most of the macroura, is elongated and 

 comparatively narrow, with nearly parallel sides, and, when perfect, 

 its length must have been about twice as great as its breadth. 

 A little in advance of the mid-length a single, broadly V-shaped, 

 deep, and rather wide cervical furrow crosses the carapace trans- 

 versely. The posterior half of the carapace is depressed and rather 

 distinctly three-keeled in a longitudinal direction. In the specimen 

 collected by Mr, McConnell a central keel, or narrow but prominent 

 raised ridge, about three times as broad posteriorly as it is anteriorly, 

 and which is bounded on each side by a deep and angular furrow, 

 extends from the posterior end of the carapace to the centre of the 

 V-shajDed (cervical) groove which transverses it. This central keel 

 is much more strongly marked than the broad and comparatively 

 obtuse lateral keels near the outer margin of each side. The surface 

 of the posterior half of the carapace (and perhaps that of the 

 anterior also) is covered with rather distant, small, isolated conical 

 tubercles, which occasionally are surrounded by a minute annulus at 

 the base ; and the three keels each have a single series of larger 

 conical tubercles, whose pointed apices are directed forward. 



" In front of the transverse and V-shaped (cervical) furrow the 

 carapace is very badly preserved, and the anterior margin with the 

 rostrum is broken off. The two lateral and tuberculated keels 

 appear to be prolonged to within a short distance of the front 

 margin of the carapace, though they are somewhat less distinct in 

 front of the (cervical) furrow than they are behind it. On the 

 anterior side of the furrow the central keel is absent, and the median 

 portion of this part of the carapace bears a number of comparatively 

 large and prominent, distinct and conical tubercles, which are some- 

 what peculiarly arranged. Next to the furrow, and in advance of it, 

 in the median line, there are five tubercles arranged in two con- 

 vergent rows of two pairs and an odd one, which, if connected by 

 lines, would have much the shape of an isosceles triangle, with its 

 base near to the furrow. Between the space bounded by these 

 five tubercles and each lateral keel there is a shallow, concave, and 

 rather broad depression of the carapace. In front of these five 

 tubercles, again, there are four others and still larger ones (the two 

 anterior ones apparently of considerable size), arranged somewhat in 

 the form of a square, any of whose sides would be greater than the 

 base of the isosceles triangle indicated by the other five. 



" The upper surface of each of the abdominal segments bears 

 a tubercle in the centre, on its anterior edge, and another one on the 

 margin of each of the sides. The most prominent characteristic 



