DITHYROCARIS BREVIACULEATA. 191 



19. Dithyrocakis Koohi, Ludwig, 1864. Plate XXIX, figs. 7, 8. (Copied from 



Ludwig's figs. 1 and 1 a, nat. size, op. cit. infra.) 



Dithtbocahis Kochi, Ludwig, 18(54. Palaeontograpbica, vol. xi, p. 309, pi. 1, figs. 

 1, la, 11, lc. 



— J. M. Clarke, 1884. N. Jabrb., 1881, vol. ii, p. 185. 



— R, W., and J., 1887. Eep. Brit. Assoc, for 1886, p. G6. 



„. „. ( Style and head (caudal plate) 25 mm. long. -\ As figured, with 



& * I Stylets 24 mm. long. Dorsal aspect. ) ends restored. 



PL XXIX, fig. 7, is Ludwig's figs. 1 a (nat. size) and 1 c ; fig. 8 is his figs. 1 

 (nat. size) and 1 b. 



The stylets coming out below the caudal plate and spreading out sideways, 

 appear to reach further than the style. 



Characters. — These caudal spines are strong and more or less bayonet-shaped. 

 The style is rather shorter than the stylets. All are represented as having on both 

 faces a central ridge, with striae on the sloping sides, pointing obliquely down- 

 wards and towards the middle. On the style and stylets the ridge is rugose on 

 the dorsal surface ; so is the ridge of the style on the ventral face, and possibly 

 that of the stylets also. 



Devonian. From the Goniatite-shales, near Herborn, in the Dillthal, Nassau. 



20. Dithyrocaris brbviaculkata, Ludiviij, 1864. Plate XXIX, fig. 9. (Copied 



from Ludwig's fig. 2, nat. size, op. cit. infra.) 



Dithyrocaris breviaculeata, Ludwig, 1864. Palaeontogr., vol. xi, p. 310, pi. ], 



fig. 2. 

 J. M. Clarke, 1884. Neues Jabrb., 1884, vol. ii, 

 p. 185. 

 — — E., W., and J., 1888. Eep. Brit. Assoc, for 1886 



(1887), p. 65. 



5 



Style (including the head, which is 6 mm. long and 5 mm. wide) 15 

 Size j mm. long. 



v Stylets 15 mm. long. 

 Characters. — The figure shows the ventral surface ; the style mid-ribbed and 

 transversely striate; and the stylets with mid-ribs simply. The style is shorter 

 than the stylets, and the latter are spread out sideways. This trifid seems to 

 have the same essential features as those of D. Kochi, Ludwig; but it is smaller 

 and the style is relatively blunter and shorter. 



Devonian. From the Spirifer- sand stone of Butzbach, Nassau. 



