CII/ENOCARIS TENUISTRIATA. 179 



Dithtrocaris tenuisteiatus, H. Woodward, 1877. Catal. Brit. Foss. Crust., p. 73. 

 Bif/shij, 1878. Thesaur. Dev.-Carb., p. 249. 



— Packard, 1883. North-Amer. Phyll., p. 452. 



— E., W., and J., 1887. Rep. Brit. Assoc, for 1886, 



p. 64. 



— — Etheridge, 1888. Foss. Brit., vol. i, Palaeoz., p. 238. 



The reference of this species to cle Koninck's Avicula {?) paradoxides, as 

 probably the same, was suggested in the 'Geol. Mag.,' 1871, p. 106; but since 

 de Koninck's determination of his fossil is avowedly doubtful and provisional, and 

 as we have not the original before us, and the figures are unsatisfactory, we can- 

 not take it as the published " type." An important remark by Prof. L. G. de 

 Koninck about his fossil is thus given in the ' Description des Animaux fossiles 

 qui se trouvent dans le Terrain Carbonifere de Belgique,' par L. de Koninck, 

 Texte, 4to, Liege, Paris, and Bonn, 1842-4, p. 139. " 15. Avicula paradoxides, 

 pi. vi, figs. 6 a, b, c. Nous sommes loin d'etre certain si cette espece appartient 

 reellement an genre auquel nous la rapportons," and in which he placed it not 

 knowing any other genus to which its form has any analogy. From the Upper 

 Carboniferous Limestone of Vise, very rare. 



Sir Richard Griffith used the name D. tenuis triatus in 1842, from M'Coy's 

 information. Sir Frederick M'Coy's description of the species, at p. 164 of his 

 ' Synopsis Char. Carb. Fossils of Ireland,' is as follows : 



" Valves eloDgate, ovate, rounded anteally, obtusely pointed retrally, convex ; mesial ridge 

 large, running nearly the entire length of the valve ; two smaller ridges close to and parallel with the 

 inner margin ; about one fifth of the length from the anterior end, and situate between the mesial 

 and internal ridges, there is a short sigmoidal ridge, and a fifth one at the anterior end defines, for a 

 short way, the line which separates the flat external margin from the convex part of the valve; 

 surface finely and regularly striated longitudinally. 



"This species differs from all others of the genus in the want of the retral spine to the valve ; it 

 is also much more convex than any of its congeners ; fragments may be discriminated by the regu- 

 larity and fineness of the striae. Length of the valve one inch, width five lines." 



The upper one of the two figures given as "fig. 3," in M'Coy's pi. xxiii, is 

 here repeated in PI. XXIV, fig. 8. The locality for this specimen is stated by 

 Sir Richard Griffith (' Journ. Geol. Soc. Dublin,' vol. ix, p. 68) to be Little 

 Island, Cork ; and at p. 100 it is referred to the Lower Carboniferous Limestone. 



PI. XXI, fig. 8. Brit. Mus., No. 32938, No. 23. 



Size. — Length of valve 40 mm. ; breadth of valve 14 mm. 



Characters. — This is a left valve, oblong, convex along the middle ; obliquely 

 rounded in front; partly rounded behind, but showing a postero-ventral spine 

 (damaged), and a notch (broken, and obscured by matrix). Surface apparently 



