part 3] CRICOIDS teom isew zealais-d. 251 



Description o£ Group C (fig. 7, p. 248). — The stem- 

 fragment composed of two columnals is cj^lindrical. 



Diameter of coliimnal=2-3 mm. 



Height of columnal = l"25 mm. Ratio to diameter = 0'54. 



Diameter of lumen = 0*25 mm. 



Sides smooth, very faintly convex, ahnost straight. 



Sutm'e-lines with large, rounded, well-marked crenellse. 



The joint-face shows a raised area round the lumen, with a 

 diameter of about 0*6 mm., and outside this are 10 radiating ridges, 

 rapidly broadening. 



The other imprint also has 10 ridges. Its diameter is 1*6 mm. 



These specimens may represent a still younger stage. If from 

 the holotype's total of 28 we were to eliminate the shorter inter- 

 calated ridges, there would be left about 10 pairs of bifurcating 

 ridges, and each of those pairs would in its early stage appear as a 

 single rapidly broadening ridge. 



Relations of the species. — At first sight the characters of 

 these imprints seem of so indifferent or uncritical a nature as not 

 to warrant the establishment of a new species. I have, however, 

 worked through the descriptions of published species without 

 finding any that agree with the diagnosis here presented. Perhaps 

 one would not expect to find the same species in the European or 

 even in the American province ; but neither is there anything 

 of the kind in the Triassic material from Timor that Prof. J. 

 Wanner has kindly entrusted to me for description. Among 

 European species similar joint-faces are found in the Carnic rocks 

 rather than in the Ladinic, where the sharjDly-cut cog-wheel type, 

 familiar in Encrinus liliiformis, is dominant. 



A tendency to bifurcation and intercalation of ridges on the 

 same plan as in JEntrochus ternio is observable in Entrochiis insignis 

 Toula. Specimens of this from the type-locality in Bulgaria Avere 

 most kindly sent to me by Dr. P. Bakalow (Brit. Mus., Greol. Dept., 

 E 14076), who has proved their Triassic age [probably Raiblian]. 

 This species shows a far more marked pentamerous fasciculation of 

 the ridges than anything hinted at in E. ternio, together with a 

 beginning of petals and radial ridge -groups. 



An earlier stage of that development is found in Encrinus 

 hyatfi W. B. Clark (1915), from the Upper Trias of California. 

 Clark lays stress on the bifurcating striations (which, by the way, 

 are scarcely shown in his figure) ; but he has not observed other im- 

 jDortant characters. In a specimen (fig. 8, p. 248) which Prof. Clark 

 was so good as to give me many years ago (now Brit. Mus., Geol. 

 Dept., E 6481) there are shorter intercalated ridges as in E. in- 

 signis, not so regular as in E. ternio. Further, the ridges are 

 clearly gathered in 5 fascicles surrounding a relatively large, 

 raised, central area, which thrusts out 5 wedges between the 

 fascicles, each wedge splitting (as it were) one of the ridges and 

 compressing the other ridges into a fan as it forces the limbs of 



