138 BRITISH PALEOZOIC PHYLLOCARIDA. 



Characters. — A semi-elliptical right valve. The surface is smooth and slightly 

 granulated locally as in fig. 1, 1)ut the longitudinal undulation, due to compression, 

 has given the false appearance of a mesolateral ridge ; and a little fracture 

 makes an artificial notch close to the antero-dorsal spine. The rim of the ventral 

 margin is distinctly depressed, but accidental pressure may have caused this. 



This specimen was figui'ed and described in the ' Geol. Mag.,' dec. 2, vol. i 

 (1874), p. lOS, pi. V, fig. 5. The outline of the antero-dorsal edge somewhat 

 differs in Mr. George West's careful photograph and lithographed figure, 

 PI. XVIII, fig. 2, from that given in the fig. 5 referred to above. 



This was also from black non-calcareous shale in the Cement-stone Quarry at 

 Glebe, Bast Kilbride. Mr. A. Paton's Collection. 



PI. XIX, fig. 1. Brit. Mus. No. 59541, No. 1. 



Size. — Length of valve 57 mm., including the spines; breadth of valve 



24 mm. 



Characters. — A fine left valve, with general features like those seen in 

 PI. XVIII, figs. 1 and 2, but there is a faint indication of a mesolateral ridge ' 

 coinciding with the depressed convexity. The ventral region is rather crumpled 

 or puckered up by pressure, and there are discolorations by the black matrix 

 where the test is thin. Both the anterior and the posterior spines are present 

 (the former not quite so perfect as showii in the figure). 



From black shale, slightly calcareous. B. Kilbride. Baton Coll. 



PI. XIX, fig. 2. Mus. Sci. and Art Bdin., " 1883, 23, 5," No. 1. 



Size. — Length of valve 60 mm., including the spines; breadth of valve 



25 mm. 



Characters. — Two displaced valves of a carapace. The left is shifted side- 

 ways over and partly beyond the right valve, and both retain a considerable 

 convexity, pei'haps indicative of the specimen having been bivalved rather than 

 of having been flatly shield-shaped. 



As in other specimens, the dorsal region of each valve bears numerous minute, 

 scattered, sharp tubercles, most apparent on the right valve (lying under the 

 other in the figure). Both the front and the hind spines are more or less evident 

 on each valve. 



From black shale, slightly calcareous. Bast Kilbride. 



PL XIX, fig. 3. Mus. Sci. and Art Edin., 1883, ^i-. No. 4. 

 Characters. — A right valve, not quite perfect, smooth, and exhibiting a faint 

 trace of a middle line. At its hinder end are the remains of two crushed abdo- 



1 Thia feature seems to give a weak foreshadowing of one of the characteristics of the next 

 species {D. granulata). 



i 



