LOWER SILURIC SHALES OF THE MOHAWK VALLEY 89 



The lateral view of one other arm exhibits the ossicles as vertical 

 bars, that are thickened at both ends resembling vertebrae and ter- 

 minating at the dorsal side with a flat surface and forming there 

 an apparently continuous layer. They appear almost twice as wide 

 as the intervening spaces. The dorsal surface bears bundles of 

 obliquely forward directed spines, one bundle corresponding to each 

 ossicle. These spines appear in the right arm to proceed from small 

 spine-bearing plates attached to the adambulacrals, as in the closely 

 related Bundenbachia. On one arm two bundles are seen to pro- 

 ceed from each segment, one oblique, the other vertical to the arm. 

 The oral skeleton consists of stout, bifid pieces, much resembling 

 the oral pairs of adambulacrals of the genotype. 



Horizon and locality. Upper Schenectady beds near Schoharie 

 Junction, Schoharie county, N. Y. 



Remarks. The genus Taeniaster was founded by Billings (title 4, 

 page 80) on the Trenton species T. spinosus and 

 T. cylindricus. The latter of these species has been 

 made the type of the new genus Taeniura by Gregory (title 31, page 

 1035) ; Parks^ however has pointed out that from inspection of 

 Billings's type specimen he would rather refer the species to Lap- 

 worthura, Gregory. However that may be, we will consider here 

 the genus Taeniaster as represented only by T. spinosus 

 and T . e 1 e g a n s Miller. In that case our specimen would 

 show the same general form and arrangement of the ossicles as 

 both these species, but differ from both by its more slender arms. 

 The shape of the ossicles resembles especially those of Taenias- 

 ter elegans, as figured by Miller,^ but we presume that 

 Miller's figure is somewhat diagrammatic. Parks states that 

 T . elegans would seem to be a true Protaster, but for the 

 fact that no disk is present. The same would be probably true 

 of our species, for Parks's figure 4, giving the ventral view of an 

 arm, presents a picture well comparable to the view of our middle 

 arm, in the shape and arrangement of the ossicles, with the differ- 

 ence that the latter in our specimen appear much thinner. 



There is no evidence observable in our specimen of any other 

 l)lates but the so-called vertebral ossicles with the possible exception 

 of the spine-bearing ossicles; it is therefore prol^able that 

 T. schohariae possessed only this interior skeleton and 

 no covering plates, a feature which is claimed by Stiirtz (title 16, 



^Canadian Institute, Trans. 1907-8, 8: 371. 



2 Jour. Cine. Soc. Nat. Hist. v. 5, 1882, pi. i, fig. 6. 



