﻿RHIZODONTTDJE. 345 



inwards, and bounded by a broad smooth space ; the 

 posterior border of the inferior expanded half is thin, and 

 immediately behind and within this border in the upper 

 half there extends an inwardly and backwardly directed 

 plate expanding upwards. 



Presented by Dr. Lauder Lindsay, 1876. 



21222 f. Eight clavicle, inner aspect, about 0-32 in maximum 

 length, shown of one-third the natural size in Plate XII. 

 fig. 3. The inferior half forms a broad triangular expan- 

 sion, laterally compressed, and the superior extremity, 

 though relatively thicker and smaller, is somewhat 

 expanded in the same plane ; midway the bone is antero- 

 posteriorly compressed, thus having a twisted appearance, 

 and the inflexion of the anterior border of the expanded 

 areas gradually diminishes above and below from this 

 point. The postero-superior inner plate noted in No. 47717 

 forms part of the upper expansion when viewed from the 

 aspect shown in the specimen now figured, and here it is 

 somewhat broken and distorted by pressure. 



Purchased, 1847. 



30533. Much crushed and broken left clavicle. Purchased, 1856. 



24841. Eight infraclavicle, inner aspect, exhibiting the elongated, 

 rod-like, postero-superiorly directed process from the 

 middle of its upper border. The bone is shown, of one- 

 third the natural size, in PI. XII. fig. 4, and is associated 

 with portions of the right mandibular ramus. 



Purchased, 1850. 



35728. More imperfect example of the left infraclavicle, showing 

 the characteristic external ornament of fine reticulations. 



Purchased, 1859. 



47726. Imperfect remains of infraclavicles associated with frag- 

 ments of mandible. Purchased, 1876. 



P. 721. Three imperfect scales ; Burdiehouse. Egerton Coll. 



P. 3323. Three imperfect scales ; Burdiehouse. Enniskillen Coll. 



An imperfect dentary bone from the St. Louis Limestone (Lower 

 Carboniferous) of Alton, Illinois, U.S.A., in the Museum of 

 Columbia College, New York, closely resembles the corresponding 

 element of B. hibberti. The laniary teeth, however, seem to be 

 more compressed, with sharper edges, and the specimen is thus 



