I.I-XANOCRINIDAE 1 39 



These show conclusively that it is a Lecanocrinus of similar general form to the other speci- 

 mens I have figured. Being also from the same horizon and locality, I have no doubt of the 

 specific identity of all these specimens, and I prefer to recognize Salter's name rather than to 

 propose a new one of my own. 



Types. Salter's .originals are in the Sedgwick Museum, Cambridge, England. Of the 

 types used herein that of figure 28 is in the author's collection ; of figure 27 in the British 

 Museum of Natural History, London. 



Horizon and locality. Silurian, Wenlock Group ; Dudley, England. 



Lecanocrinus angulatus n. sp. 



Plate II, figs. 2/^a-c 



A large species. Crown obconic, spreading gradually from base to IIBr 3 , 

 where height to width is 1 to 1.3 ; base truncate, large, not protuberant. Surface 

 smooth. Crown too much distorted for general measurements; 19 mm. high by 

 24 mm. wide at IIBr 3 ; 9 by 18 mm. at top of radials; column facet, 7 mm. 



IBB large, visible in side view. BB large. RA small. Anal x extremely 

 large, fully half of it being above the line of the radials ; and eight- or ten-sided 

 because abutting upon two and perhaps three pairs of plates beyond the radials. 

 RR small ; height of B to R to IBr, 5:5:2.5. IBr 2, large, half as high as RR, 

 and increasing in width ; they have an angular median ridge obscure on RR 

 and becoming sharper upward. Column facet as wide as base; not indented. 



I have proposed this species for the reception of a very singular form found by 

 Mr. Liljevall among some specimens in the Riks Museum labeled Ichthyocrimts, which 

 after cleaning was seen to possess a combination of characters somewhat puzzling as to its 

 generic position. The specimen is abnormal, having only four basals, but the species is not 

 based upon the abnormal features. It belongs to the class of species with small radials and 

 large and widening primibrachs, which produce rays characteristic of Ichthyocrimts; and in 

 the angularity of the rays it differs from other species. 



The remarkable thing about this crinoid, and that which causes me to direct especial 

 attention to it, is the presence of a well-defined row of interbrachial plates between the rays 

 from the IIBr upward. This is distinctly shown in position in figure 24a of Plate II, but the 

 same kind of plates may be seen in figure 24b lying scattered between the left posterior and 

 left anterior rays. It is therefore evidently a definite structure in the specimen, which thus 

 exhibits a tendency to take on interbrachial structures inconsistent with the definition of this 

 genus. I have not made this a specific character, because I am disposed to regard it rather 

 as a sporadic development, analogous to the single intercalated plate we sometimes see in 

 Ichthyocrinus; it occurs only between the higher brachials, the primary plates not being 

 separated as in genera having regular interbrachials. Therefore even if this should be a con- 

 stant character the species might still be retained in the genus, where it would represent, as 

 this individual undoubtedly does, a transition form. 



Type. In the Riks Museum, Stockholm, Sweden. 



Horizon and locality. Silurian, Wenlock Group, horizon d; Dalhem, Gotland. 



