684 REPORT OF NATIONAL MUSEUM, 1898. 



skulls were found by Mr. J. B. Hatcher, of the Princeton exploring 

 expedition. These crania represent two genera, Rhineura Cope, still 

 existing, and Hypsorhina Baur, extinct, and both are more nearly allied 

 to Lejmlosternum than to Amphisbwna. The species are termed R. 

 hatcherii and H. antiqua. 



This interesting discovery explains the existence of Rhineura in 

 Florida, and relieves us of the necessity of supposing an immigration 

 of Lepidosternoid reptiles from the South American continent, a 

 hypothesis which is the more difficult to sustain, since there are no 

 Amphisbsenidfe in Mexico or the West Indies. 



RHINEURA Cope. 



Bhineura Cope, Proc. Acad. Nat. Sci. Phila., 1861, p. 75'.— Boulenger, Cat. Liz. 

 Brit. Mu8., II, 1885, p. 459. 



Body vermiform, without legs, no ears, and the eyes invisible. Body 

 encircled by a succession of continuous whorls, divided into square 

 plates. Pectoral plates rather larger than elsewhere. Teeth conical, 

 distant, pleurodont, none on the palatine. Tongue fleshy, narrow, ovate, 

 emargiuate behind and slightly bifiid anteriorly; attached except at 

 the tip. Tail flat, with tubercles in transverse series. Nostril pierced 

 in a distinct nasal plate. 



Osteolof/y. — A specimen of the R. floridana Baird from Volusia, Flor- 

 ida, furnishes the characters of the skeleton. 



The alveolar border of the premaxillary is very short, and supi)ort8 

 only one, a median tooth. The spine is divided into two portions, that 

 below the projecting angle of the muzzle and that above it. The former 

 is contracted a little by a process of the maxillary which enters from the 

 alveolar portion, separating it from the nostril, which is inferior in posi- 

 tion. It then expands a little, to form on the upper side of the muzzle 

 a terminal expansion twice as wide as long. The nasals are distinct, 

 and extend to the border of the muzzle, overroofing the nostrils. Fron- 

 tals wide, distinct, deeply emargiuate posteriorly for the parietal. Pre- 

 frontal rather large, triangular, sending its apex posteriorly over the 

 orbit and reaching the parietal. Its free border and a narrow band of 

 the parietal form a crista temporalis, which do not unite on the middle 

 line into a crista sagittalis. Parietal single, without pineal foramen, 

 continuous laterally with the petrosal and alisphenoid, and posteriorly 

 with the supraoccipital, from which it receives on the middle line a 

 gomi)hosis. Supraoccipital bounding foramen magnum, of which it 

 forms a rather narrow border. A small triangular bone at the extrem- 

 ity of the maxillary may be a jugal or a lachrymal. The alisphenoid 

 and petrosal form the inferior part of the side walls of the brain case, 

 and are separated from the pterygoids and presphenoid below them by 

 a narrow fissure M^hich is widest below the petrosal. The latter sends 

 an angle upward and backward between the parietal and exoccipital. 

 The exoccipital sends a prolongation (paroccipital?) downward and for- 



