DITHYROCARIS TESTUD1NEA. 153 



PI. XXIX, figs. 10 a, b ■ 11 a— d; 12 a, b ; 13 a—c ; 14. Neilson Coll., J. 

 Size : 



Fig. 10. — 8 ram. long, 8 mm. wide. A fragment. 

 5, 11- — 11 jj 8 ,, Imperfect in length. 



,, 12. — 11*50 ,, 6 ,, Nearly perfect in length, imperfect 



in width. 

 „ 13. — 7*50 ,, 5*50 ,, A fragment. 



,, 14. — Diagram of the ornament. 

 Characters. — These four abdominal (caudal) segments (more or less imperfect) 

 are cylindrical, and bear chevron-lines similar to those of D. testudinea in PI. XXI, 

 fig. 4. Similar ornament is present in PI. XXI, fig. 10, which we refer with 

 some doubt to I). Scouleri. 



Judging from PI. XXI, fig. 4 (page 149), in which the ventral face is 

 upwards, fig. 11a, having the chevrons pointing downwards (backwards in the 

 living animal), presents its under side. Its interstitial ornament (fig. 11 b) cousists 

 of an extremely delicate porous reticulation, with larger pores widely scattered. 



Figs. 10 a and 12 a, for the same reason, must be taken as dorsal aspects. A 

 delicately crimped edge or fringe marks the lowest part of the test of these 

 segments just above the distal joint, to which the trifid spines were probably 

 attached. The ornament (fig. 12 a 1 ) consists of the smooth raised strige (chevron- 

 lines) and punctate interspaces. These segments have been somewhat crushed, 

 so that the lower end is broken (fig. 12 b), and the sectional area (figs. 10 c and 

 12 c) is suboval. 



Figs. 13 a, b, retain a part of the top of the segment complete, but otherwise 

 the specimen has been damaged at the end and side (figs. 13 a, b). The spines of 

 the crimped edge of the test have been broken off. Figs. 13 a — c show a short 

 cylindrical fragment. 



In all of these four segments it is observable of the chevrons that those on 

 one face point in an opposite direction to those on the other face, so that one 

 chevron continuing on the two sides forms an elegant lozenge pattern with rather 

 blunt angles, as shown in the diagram, PI. XXIX, fig. 14. 



In black shale. Two from Calderside ; and two from Kirktonholme. 



Dithjrocaris testudinea, Scouler ; W. Hind, 1897, ' Geol. Magaz.,' dec. 4, vol. iv, 

 p. 208; and 'Monograph Carbonif. Lamellib.,' Pal. Soc, p. 93. 



A specimen obtained by Dr. Wheelton Hind, F.G.S., from a quarry on 

 Congletou Edge, Cheshire, was noticed by him in 1897, in his memoirs above 

 referred to. 



It is too much broken by pressure and crush to be serviceable as a figured 

 specimen ; but we may notice that it has remains of the gastric teeth. 



