24 - F. A. BATHER, CRINOIDEA OF GOTLAND. 



stellate centra] canal, but without adducing evidence. They were the first to caU attention 



to what I have elsewhere ') called the »radial processes». 



In November, 1888, Messrs Wachsmuth and Springer 2 ) published a figure that 

 purported to show the »Inner floor of the orals of a Pisocrinus from Indiana,» and said 

 {pp. cit. p. 350) »We now recognise ... in Pisocrinus five large orals as coyering the 

 greater part if not all of the ventral surface.» 



In 1890 Mr. S. A. Miller 3 ) introduced into a description of his family Pisocrimdae 

 some ideas as to the »subradial» nature of the plate hitherto usually called azygous: and 

 of the lower part of the two larger radials. Since Mr. Miller's »subradials represent th'j 

 basals of modern scientific terminology, this would make Pisocrinus a dicyclic form; Mr. 

 Mm. ler placed it, nevertheless, among »Genera having tive Basals, no Subradials, no regular 

 Interradials.» In this connection it may be mentioned that Dr. Otto Follmank in 1887 4 ) 

 called the »azygous» plate of both Triacrinus and Calycanthocrinus a »Parabasal», while the 

 plates called »Basalia» in his text were lettered »IB» in his figures. 



Quite recently Mr. S. A. Miller 5 ) has described three new speeies and has given 

 ns further views on the morphology of the genus. He suggests that the three large eup- 

 plates »might be defined as . . . primary radials» and the smaller ones as Three secondary 

 radials». This is quite unnecessary. He talks about »arm-blades» as taking the place of 

 arms, a view that appears to be suggested ty the occurrenee of a rather long tirst brachial 

 in P. Gorbyi. In this connection he quotes Angelins descriptions of arm-bearing Piso- 

 crini, but suggests that the Swedish and American speeies are not congeneric. In Pl. VI, 

 tigs. 24, 25 he represents »the convex side of two plates tirst diseovered by Mr. A. C. 

 Benedict associated with Pisocrinus and which he supposed to be the vaults.» It was the 

 under or concave side of one of these that was tigured by Wachsmuth in 1888 {loc. cit.) 

 Of these two plates Mr. Miller gives a very full description, from which it appears that 

 there are no sutures in them, that ten large ridges or folds radiate from the apex and 

 that between them arise ten smaller ridges, that on the concave side depressions correspond 

 with these ridges. »The tive grooves on the under side may represent the continuation 

 of the channels to the central part of the visceral cavity.» On the other hand there is 

 no indication of an anal orifice, as one would certainly expect. There is no direct evidence 

 that these plates belong to Pisocrinus, and they look far more like cup-plates with pro- 

 nounced radiate ridging than they do like fused orals. 



The changes that will now have to be made in the Terminology of the plates will 

 be best understood by comparing the accompanying diagrams, which represent the cup oi 

 P. pilula (text-figs. 1 and 2). The position of the anal tube of course determines the 



') Trigonocrinus <fcc.» Quart. Journ. Geol. Sop. London, vol. XLV, p. 151; Feb. 1889. 



-) Ventral Structure of Taxocrinus etc.» Proc. Ac. Nat. Sci. Philadelphia, 1888, Pl. XVIII. 6g. 14. 



:i ) A mer. Tal. Crin.» Anier. Geol. vol. VI, p. 350. 



J ) Unterdevonische Crinoiden», Verh. nat. Ver. preuss. Rlu-inl., Jalirg. XLIV, Hälfte 2, pp. 114 — 110. 

 Pl. 11, figs. la and 2 e; Bonn. Thosc who possess author's copies of this paper have doubtless found to their 

 sorrow that it has been repaged and the plates renumbered, while all reference to the original place ut' publicatiou 

 has been e;irc!'ull\ renioved. When will authors leani how irritating this form of \;mit\ is? 



') Advanee Sheets from the 17th Report of the Geol. Surv. of Indiana. Palseontology, pp. 20 — 32, Pl. VI, 

 figs. Ii» 25, Pl. XI. figs. 4, 5; liidianopolis. Aug. 1891; sold as a separate publication. 



