74 Dr. F. A. Bather — Notes on Yunnan Cystidea. 



Hall had recognized that the name ITolocystis had been used by 

 Lonsdale in 1849 for a Cretaceous coral; he therefore proposed 

 (1865, p. 380; 1870, p. 429) to replace his own Holocystites by 

 Megacystites. To clear this matter of nomenclature out of the way 

 at once, it may be mentioned that, though Hall's proposal was 

 entirely overlooked by S. A. Miller, it was adopted by Sven Loven 

 in editing Angelin's " Iconographia Crinoideorum " (1878), bv 

 P. H. Carpenter (1891, J. Linn. Soc, Zool. XXIV, p. 47) and 

 by myself (1900, Treatise on Zoology, p. 47). "We have all used the 

 form Megacystis, recognizing no difference but that of length and 

 cumbrousness between the ending in -ites and those in -us, -a, or -is. 



Beyond the general shape and the number of plates, very little 

 could be ascertained by Hall from the material at his disposal. In 

 December, 1865, A. "Winchell and 0. Marcy (Mem. Boston Soc. 

 Nat. Hist. I, p. 9) described a new species, C. spharicus, from the 

 Niagara [Racine] Limestone of Chicago, and mentioned a fine 

 specimen of Caryocystites cylindricus, showing the anus. 



The Ifegacystis ovalis of Angelin (1878, p. 30) belongs to the 

 Rhombifera, and his " M. alternata, Hall, var." (loc. cit.) is a fragment, 

 supposed from Kinnekulle, which may have belonged to any large 

 elongate Sphceronid of Ordovician age. 



It was not till October, 1879, when S. A. Miller (Journ. 

 Cincinnati Soc. Nat. Hist., I, p. 129) began the description of 

 species from the lower part of the Niagara Group in Indiana, that it 

 was possible to form an adequate idea of the genus. Miller continued 

 his descriptions through many years, 1 and raised the number of 

 names for North American species from seven to forty-eight. In 

 1889 (op. cit.) Miller fixed the genotype as H. cylindricus Hall. 

 The original of Hall's figure 16/1 of " Caryocystites cylindricum'''' is the 

 holotype of the species (= pi. xii, fig. 4, and pi. xiia, fig. 7, of Hall, 

 1865-67). 



Unfortunately Miller's conceptions of Echinoderm morphology 

 were old-fashioned when he began and underwent no change. In 

 reading his descriptions his use of the following terms must be kept 

 in mind: — 



' ' Ambulacral orifice ' ' Miller = mouth or peristome. 



"mouth" ,, =anus or periproct. 



" anal aperture " ,, = hydropore, but may sometimes = gonopore. 



' ' ventral " or " anterior " , , = posterior. 



" dorsal' ' or " posterior " ,, = anterior. 



" right " and " left " ,, = left and right. 



A list of the American species, with references, will be found in 

 R. S. Bassler's "Bibliographic Index of American Ordovician and 



Journ. Cincinnati Soc. Nat. Hist., ii, pp. 104-8. 



Tom. cit., p. 259. 



Op. cit., v, p. 223. 



N. Amer. Geol. and Pal., pp. 253-5. 



Adv. Sheets 17 Eep. Geol. Surv. Indiana, Palaeontology, 



pp. 13-18. 

 Ditto, 18 Eep., pp. 8, 9. 



With Faber. Journ. Cincinnati Soc. Nat. Hist., xv, p. 87. 

 With W. F, E. Gurley. Bull. Illinois State Mus., v, pp. 5-8. 

 With W. F. E. Gurley. Op. cit., vii, pp. 84-6. 



