NATURAL SCIENCES OF PHILADELPHIA. 1:'. 



quarter inches long and three-quarters of an inch wide, gradually tapering to 

 seven lines, and is provided with about seven and a half dentate proce 

 The other fragment is three and three-quarter inches long, seven lines wide 

 below, and four lines at the broken apex, and is provided with nine dentate 

 processes. 



The segmented condition of the ray recalls to mind a singular fossil speci- 

 men formerly described by me as the portion of a jaw of a fish to which the 

 name of Edestus vorax (Jour. Acad. Nat. Sci. iii, 159, pi. 15) was given, and 

 which also exhibits a segmented condition. This fossil, notwithstanding its 

 jaw-like appearance furnished with shark-like teeth, I have always suspected 

 was an ichthyodorulite (Proc. 1856, 301), and this suspicion is increased by 

 an examination of the rays supposed to pertain to Ptychodus. 



Asteracanthus siderius. The species is founded on a fragment of an 

 ichthyodorulite, found on a stream near Glasgow, Tennessee. The specimen 

 was submitted to my examination by Prof. J. M. Safford, through Prof, llayden. 

 It purports to be of subcarboniferous age, but perhaps this is an error, for all 

 the previous known fossils attributed to the genus are of much later age. It 

 looks as if in its complete condition it had approximated in size the dorsal 

 spine of Asteracanlhus ornatissimux, which is a foot and a half long. The frag- 

 ment is from an intermediate position at the junction of the root and shaft, and 

 is a little over three inches in length. Broken at the extremities, and posteri- 

 orly, so as to leave no remains of a groove, it is composed of solid porous bone, 

 and is triangular in transverse section. The triangle of the shaft has a base 

 seven lines thick ; the sides are about three-fourths of an inch wide, and the 

 apex is rounded. The root is compressed laterally to a greater degree than 

 the bottom of the shaft, and in the fragment is an inch and a half wide. 



The lateral surfaces of the shaft are closely covered with large mammillary 

 tubercles, which have been worn off at the summits. These tubercles are of 

 enamel-like hardness, brown and lustrous. Their sides are closely and longi- 

 tudinally wrinkled; the fewer wrinkles near the apex becoming branched ami 

 more numerous approaching the base. The tubercles are situated in parallel 

 longitudinal rows, having a slight obliquity. The intervals formed by the 

 divergence of the longer rows near the root are occupied by shorter rows. 

 About thirteen rows, including the short ones, may be counted on one side of 

 the specimen at the verge of the root. 



Prop. Leidy further observed that the two fossils presented this evening by 

 Henry Green, of Elizabeth, Jo Daviess Co., Illinois, through Dr. Edward D. 

 Kittoe, of Galena, were of considerable interest. They consist of a metacarpal 

 bone of the Giant Sloth of Jefferson {Megalonyx Jeffersoni), and a last lower 

 grinder of the extinct Ox, Bison antiquus. They were discovered, in the search 

 for lead, iu a narrow crevice of the lead-bearing rocks, at the depth of 130 

 feet, in the vicinity of Galena. A number of other bones were found at the 

 same time, but, unfortunately for the interests of science, these are scattered 



or lost. . 



The museum of the Academy contains fossils which were found in a similar 

 position in the same locality some years back. Of these, some were presented 

 by Dr LeConte, who obtained them from Mr. Snyder of Galena; others were 

 presented by my friend Dr. Kittoe. They consist of remains of an extinct 

 Peccary, Platygonus compressus, larger than the existing species; an extinct 

 Raccoon, Proa/on priscus, and a large insectivore, named in honor of Mr. bny- 

 der, Anomodon Snyderi. These animals were probably cotemporanes of the 

 former. 



Mr Thomas Meehan said that no one who examined the prevailing theories 

 concerning the formation of bark and wood with numerous living specimens 

 before him, could be satisfied that these theories were in all respects correct. 

 He had made numerous observations during the past year, which satisfied nm 

 that at any rate we had much to learn. He hoped to present these observa- 



1870.] 



