188 BRITISH PALEOZOIC PHYLLOCARIDA. 



broken across in two places, and damaged by crush at the upper end, was probably 

 25 mm. long. It is marked with long linear chevrons, pointing obliquely down- 

 wards (backwards) from the sides, and meeting along the middle (characterising 

 the ventral aspect). The interstitial spaces bear delicate, transverse, sinuous 

 lines. A fragment of the crushed penultimate segment remains. 



There are remains of three broad tail-spines (the fragments being 5, 5, and 7 

 mm. long). The middle one (style) is sulcate and flattened. The stylets are 

 strongly striated with six costulse ; they are broader than the style. The heads 

 of all three are crushed together under the terminal arch of the ultimate segment 

 (more clearly seen in the photograph). 



This specimen differs from that in fig. 4 (ventral aspect) of the same plate, 

 and fig. 4, PI. XXXI, in both size and shape, being larger. Nevertheless it is 

 probably closely related to it (D. testudinea). 



Some resemblance to the above-described may be seen in the smaller segments 

 and trifid appendage of the Upper Silurian Ceratiocaris compta (pi. VII, figs. 

 10 a, b, p. 57, ' Monogr. Foss. Phyllop.,' Pal. Soc, 1888). In this, showing its 

 dorsal surface, the oblique lines of ornament converge forwards (upwards on the 

 figure), and not backwards. 



The specimen under notice has some points of agreement with that shown in 

 M'Coy's figure of his D. Scouleri (see PI. XXY, fig. 6 a), but we do not associate 

 it with that species, for the relative measurements of the few perfect portions do 

 not agree closely enough, and there are doubtful details in the fig. 6 a. 



From East Kilbride. Paton Collection. 



10. Sp. (?) Mus. Geol. Surv. Scotl., F 7 -|L, No. 22 m, 998 b (not figured). 



A caudal extremity consisting of two abdominal segments and three tail-spines, 

 showing the ventral aspect. They are all very much crushed, but the fragmentary 

 segments show linear ornamentation like that in fig. 10, PI. XXI. The spines are 

 coarsely striate, as also in fig. 10. 



From the Calciferous Sandstone group ; Leet Water, below Hirsel, Cold- 

 stream. In dark grey, micaceous, calcareous shale. 



17. Rhachuka (Dithyeooaris?) vunosa, Scudder, 1878. Plate XXIX, fig. 4. 



(Copied from Scudder's fig. 3, op. cit. infra.) 



HiiACHURA vknosa, Scudder, 1878. Proceed. Boston Soc. Nat. Hist., vol. xix, 



pp. 29G— 299, pi. ix, figs. 3, 3 a. 

 — Packard, 1883. Monogr. N.-Amer. Phyllop., p. 152. 



