68 PROCEEDINGS OF THE ACADEMY OF 



The caudal vertebras of Hadrosa uras are biconcave or amphiccelian ; those 

 of Thespesius, at least the larger, more characteristic ones, are convexo-concave 

 or opisthoccelian. 



In the present condition of knowledge of the remains of Hadrosaurus and 

 its allies, the following appear as distinct: 



HADROSAURUS. 



Caudals biconcave or amphiccelian ; cervicals and dorsals convexo-concave 

 or opisthoccelian. 



Hadrosaurus Foulkii. 



Leidy : Pr. A. N. S. 1858, 218 ; Cret. Rept. U. S. 1865, 76, pis. ii, figs. 9 

 11 ; viii, fig. 13 ; xii, xiii, figs. 1 19, 24 28 ; xiv xvii, figs. 4, 5. 



Crowns of the teeth tuberculate at their enameled margins. 



Hadrosaurus mirabilis. 



Trachodon mirabilis, Leidy: Pr. 1856, 72 ; Trans. Am. Phil. Soc. 1859, 140. 



Crowns of teeth non-tuberculate at the enameled margins. 



Remarks. The non-tuberculate character of the borders of the teeth was 

 not unlikely associated with others in the skull, &c, which if known would 

 probably separate this species as a distinct genus from Hadrosatirus. 



Hadrosaurus tripos. 



Cope: Pr. A. N. S. 1869, 192. 



Founded on several caudals from the cretaceous formation of Sampson Co., 

 North Carolina. The robust character of the vertebras, with their strongly 

 developed articular processes ior chevrons, recalls to mind the caudals of 

 Iguanodon, as represented in Tab. xxxvii of Owen's Monograph of the Reptilia 

 of the Cretaceous Formation, published by the Palreontographical Society. 

 The specimens probably represent a true Iguanodon. 



Hadrosaurus minor. 



Marsh : Pr. A. N. S. 1870, 2. 



Indicated by several vertebra; from the cretaceous green sand of New Jersey. 



THESPESIUS. 

 Caudals convexo-concave or opisthoccelian. 



Thespesius occidentals. 



Leidy: Pr. A. N. S. 1856, 311 ; Trans. Am. Phil. Soc. 1859, 151, pi. x, figs. 

 15. 



Hadrosaurus (?) occidentalis. Cope: Syn. Ext. Batr. and Rept., Aug., 1869, 

 98. 



It is not improbable that part or the whole of the teeth originally referred 

 to Trachodon mirabilis may belong to this animal. Even if such should prove 

 to be the case, the different character of the vertebra? would render Thespesius 

 quite distinct from Hadrosaurus or Trachodon. 



It is uncertain, nay improbable, that the small caudal, with the plano-con- 

 cave body, represented in figs. 6, 7, pi. 10, of the Trans. Amer. Philos. Soc. 

 1859, should belong to Thespesius occidentalis. 



Prof. Leidy next made some remarks on the family of the Vinegar-eels, the 

 substance of which was as follows: The number of species and genera of ne- 

 matoid worms, represented by the Vinegar-eels, and constituting the family 

 AnguillulidiTj is astonishingly great. They are found in multitudes frequently 

 in and about moist decaying and fermenting organic substances. Mr. Bas- 

 tian, of London, a few years since contributed to the 2-5th volume of the 

 Transactions of the Linnean Society a paper, in which he has given descrip- 

 tions, with characteristic figures, of most of the known species, including 

 about one hundred new ones, which he observes he discovered from a few 



[June* 



