CARYOCARIS WRIGHTII. 



91 



Fig. 5. — C. Wrightii. 

 Compressed carapace show- 

 ing right valve. Huy, Bel- 

 gium. 



some small caudal styles which may possibly have belonged to species of the 

 genus, though they somewhat resemble those associated with the Upper-Silurian 

 Peltocaris and Discinocaris in the Coniston Mudstone of Skelgill, also collected by 

 Mr. Marr. 



Professor Lapworth records the occurrence of Garyocaris W^'ightii in. the shales 

 of Arenig age at Bennane Head, in the Ballantrae area, on the Firth of Clyde 

 (' Geol. Mag.,' 1889, p. 22). 



Professor C. Malaise, of Gemboux, has obligingly lent us three specimens of 

 C. Wrightii, obtained by him from the Arenig series of Huy and Nannine, 

 Belgium. Of these specimens, one is large (Fig. 5, woodcut), one imperfect, and 

 one small with a trifid tail partly extruded from below the narrow extremity 

 (Fig. 6, woodcut). They are black and shiny; in hard, 

 black, micaceous shale, jointed, with ferruginous facings. 



The small specimen with caudal appendage is of great 

 interest : first, because it corroborates our opinion that the 

 smaller end is the posterior extremity of the valve ; secondly, 

 because in it we have the only certain evidence of the form 

 of the cercopods in this animal (Fig. 6, woodcut). They are 

 not wholly exposed, but evidently comprise three lancet- 

 shaped, flat, thin, blade-like members, one of which, apparently 

 larger than the others, as far as they are exposed, may be the 

 style or chief cercopod. We do not know any set of style 

 and stylets exactly corresponding to these. Those of Ehj- 

 mocaris (Beecher, ' Report Geol. Surv. Pennsylv.,' 1884, 

 p. 13, pi. ii, fig. 1) have a close resemblance : so also E. ? longi- 

 cauda (Sharpe), supra. Part I, PI. XI, fig. 16 a ; and G. patula, ib., fig. 11. One 

 of the nearest in shape (but not in size) is the much larger trifid set of caudal 

 appendages belonging to a Carboniferous species of Dithyrocaris (undetermined) 

 described and figured by Mr. R. Etheridge, jun., in the ' Quart. Journ. Geol. 

 Soc.,' vol. XXXV, 1879, p. 466, pi. xxiii, fig. 2 ; and those of D. testudineus, 

 Scouler, ' Geol. Mag.,' 1873, pi. xvi, fig. 1. 



The larger specimen (Fig. 5, woodcut), measuring 27x10 mm., has the 

 ordinary shape, like PI. XIV, fig. 13 ; Fig. 6, woodcut, is smaller (19 X 7-5 mm.), 

 and more crushed. 



Fig. 6. — C. Wrightii. 

 Compressed carapace show- 

 ing left valve and the trifid 

 caudal appendage ; with 

 fragments of other valves ? 

 Huy, Belgium. 



