ICHTHYOCRINIDAE 33 1 



Wachsmuthicrinus spinifer (Hall) 

 Plate XLIV, figs. 1-5 



Forbes'wcrinus spinifer Hall, Jour. Boston Soc. Nat. Hist., VII, i86r, p. 318; Descr. New Species Crin., 



p. g {spiniger). 

 Taxocrinus spinifer, Meek and Worthen, Proc. Acad. Nat. Sci. Philadelphia, IX, 1865, p. 140. 

 Taxocrinus thiemei, Meek and Worthen (not Hall), Geol. Surv. Illinois, V, 1873, p. 399, pi. 4, fig. 1. 



Generally similar to W . thiemei, except in the extremely prominent spines, 

 and in having the ramules at shorter intervals. The spines, which give to the 

 species a very unusual appearance for this group, are almost wholly confined to 

 the axillary primibrach, which is produced to such an extent as to resemble the 

 spines on the radial dome-plates in the Camerate genus Dorycrinus. In 

 W . thiemei the nodes sometimes become sharp, like spines, but they are small, 

 short, and distributed throughout the ray; whereas here the spiniferous ten- 

 dency is concentrated on one plate, the other axillaries showing it but rarely. 

 The ramules, as shown by four specimens, seem to be constantly rather closer 

 together, being on ever}' second brachial in the upper half of the rays, and the 

 intervening brachials becoming short and pointed. There is also greater de- 

 velopment of interbrachials in this species than in the last, these plates occurring 

 alike in large and small specimens. 



The species has been found in the equivalent of the Lower Burlington strata at Lake 

 Valley, New Mexico. I have also figured some isolated spinous axillary plates from the 

 Kinderhook beds at Fern Glen, Missouri, indicating that this or a similar species existed at 

 that horizon, slightly below the beds at Burlington. 



Meek and Worthen considered the species synonymous with W . thiemei, and so figured 

 the fine specimen here shown by Plate XLIV, figure la. 



There has been some confusion as to the name, whether it should be written spinifer or 

 spiniger, having been used by Hall in the latter form in his preliminary description. But this 

 pamphlet, so far as can be ascertained from the dates borne by the publications themselves, 

 did not appear until after the full description in the Journal of the Boston Society of Natural 

 History, January, 1861, in which the name is printed "spinifer." 



Type. The type of Hall's description, formerly in the collection of Dr. Charles A. White, 

 is a very imperfect specimen, and was not accessible when the drawings for this work were 

 prepared. It is now in the author's collection, as are the other specimens here figured, except 

 that of figure la, which is in the Museum of Comparative Zoology, Harvard. 



Horizon and locality. Lower Carboniferous, Lower Burlington limestone; Burlington, 

 Iowa, and Lake Valley, New Mexico ; and also Kinderhook, Fern Glen, Missouri. 



