480 FRANK SPRINGER 



radianal, but it is perfectly developed in the specimen (Plate VI, Fig. 

 9), and also in another one since found. In A. angelini W. and Sp. 

 (figured by Angelin as Lecanocrinus macro petalus) his first specimen'' 

 has no radianal, and the figure is correct in this respect; but the 

 second specimen^ has a very distinct radianal, situated obliquely 

 under the left corner of the right posterior radial; while in a third 

 specimen, found since Angelin, the radianal is large, and fully under 

 the radial (Plate VI, Fig. 10). It is quite possible that the first 

 specimen does not belong to this genus, as there is some difference 

 also in the arms. 



These two genera differ from Homalocrinus and Calpiocrinus in 

 having very large basals. It is interesting to note that both of them 

 occur in America. Lecanocrinus greenei of Miller and Gurley,^ and 

 L. oswegoensis,"^ both belong unquestionably to Anisocrinus. Miller 

 and Gurley's figure of L. greenei shows nothing of the radianal, which 

 is plain enough in the specimen, cut oft' from the lower left part of 

 the right posterior radial (Plate VI, Fig. 11); but in the other species 

 it is shown in their Fig. 16 (Plate VI, Fig. 12). The Clidochirus is 

 an undescribed form from our western Silurian. 



Liljevall's drawings also enable us to understand the rare genus 

 Calpiocrinus, which turns out to be a very curious and extraordinary 

 affair (Plate VII, Figs. 1-8). Angelin described it as having three 

 basals and no parabasals, or, as we should say now, three infrabasals 

 and no basals. Wachsmuth and Springer^ were much puzzled by 

 the fact that this genus, as described by Angelin, seemed to have 

 but one ring of plates below the radials; but expressed the opinion 

 that this ring of plates "is the analogue of the underbasals, and*that 

 the true basals, if not absent, are exceedingly rudimentary." Dr. 

 Bather, on the other hand,^ states that Calpiocrinus "has minute, 

 often obsolete IBB, but fairly large BB." The facts now disclosed 

 show that Angelin's description was wrong; but that Wachsmuth 



1 Ibid., Plate XIX, Fig. 3, and Plate XXII, Fig. 24. 



2 Ibid., Plate XIX, Fig. 4. 



3 Bulletin No. 8, Illinois State Museum, Plate III, Fig. 28. 



4 Ibid., No. 4, Plate III, Figs. 15, 16. 



s Revision oj the Palceocrinidce, Part I, p. 38. 



^ Lankester's Treatise on Zoology, Part III, p. 189. 



