82 retort — 1884. 



III. Pholadocaris, H. Woodward, 1882. ' Geol. Mag.' Dec. 2, vol. ix. 



p. 388. 



The shield of this Phyllopod is peculiar, and is described in careful 

 detail, Joe. tit. Its main features are that two furrows radiate from the 

 centre backwards, enclosing a narrow triangular space, marked with 

 parallel radiating lines. Radiating and concentric lines ornament the 

 lateral portions of the cai-apace. In front of the centre two slightly 

 raised elliptical ridges enclose a small space behind the apex of the large 

 V-shaped nuchal suture, and in the fig. 16 remind us of the two forward 

 ridges iu Lisgocaris ; whilst the two furrows behind feebly represent its 

 posterior ridges. 



1. Pholadocaris Lceii, H. W\, 1882. Loc. tit. pi 9. f. 16. 



The only specimen described with the above characteristics has a 

 triangular-obovate, or nearly cuneiform shield ; broadly rounded in front 

 (when complete) ; narrow and rounded behind. Complete, about 34 mm. 

 long ; 16 mm. broad at the widest part. Rostral piece about 10 mm. 

 long, and 10 mm. wide in front ; slope of notch about 60°. From the 

 Upper Devonian of Biidesheim in the Eifel. 



2. Pholadocaris, sp. Aptyclms of a Goniatite, F. A. Roemer. ' Palaeon- 

 tographica,' vol. iii. 1850, p. 88, pi. 13, fig. 13. 



This neat figure of an obovate, notched, concentrically marked, black, 

 filmy fossil from the Goniatiten-Schichten of Altenau, in the Hartz, would 

 serve for some Discinocaris, if it were not that the posterior portion is 

 marked with a dark (sunken) elongate-triangular space, beginning behind 

 the centre and widening out slowly to the posterior margin. Altogether 

 we may take the figure to represent an ill-preserved Pholadocaris, neatly, 

 but possibly not quite correctly, drawn. 



Pholadocaeis. 



Pholadocaris Lceii, (in Goniatite bed) .... Eifcl. 



sp- 



Hartz. 



IY. Lisgocakis, J. M. Clarke, 1882. 'Amer. Journ. Science,' ser. 3, 

 vol. xxiii. p. 478, pi. O, fig. 5 ; vol. xxv. p. 124. 



This also belongs to the group of fossil Phyllopods which have 

 shields without a median dorsal suture. It has concentric lines of 

 growth also, following the marginal contour of the test. 



The difference between this and Discinocaris is that it has a rounded 

 or elliptically cut cephalic notch (if looked at as we regard it, instead of 

 posterior or abdominal, as at p. 478, op. cit.) Its outline is symmetrically 

 subpentagonal. Three ridges leave the apex or centre of the shield, one 

 central and one on each side, and radiate to the hinder margin, which 

 they stretch out, as it were, into three points, with two intervening 

 concave spaces. In front two low ridges pass away obliquely forward 

 and outward from the centre, and between them is the long, narrow, 

 round-ended cephalic notch, the shape of which is distinctive. 



1. Lisgocaris LutJieri, Clarke, 1882 (he. cif.), is the only described 

 species, and exhibits the features above-given. Its figure is about 40 mm. 

 long and 30mm. wide; cephalic notch 10mm. wide at its entrance, 

 17 mm. long, and not narrowing very much before it begins to curve 

 round at its apex. 



