﻿552 ADDENDA ET C03VRIGENDA. 



41866-67. Three examples of the left mandibular tooth, the 

 largest measuring 0*015 from the symphysial to the 

 post-oral border ; Kimmeridge Clay, "Weymouth. 

 The symphysial, median, and posterior outer tritors 

 are represented, but the median is very narrow, and 

 the anterior outer tritor is absent or not differen- 

 tiated from the median. The beak is small ; the oral 

 margin is relatively short and faintly wavy, with a 

 slight prominence at the posterior outer tritor ; and 

 the post- oral margin is nearly parallel to the sym- 

 physis. The oral face is much upturned. 



Purchased, 1869. 



P. 72. The following tooth, also from the Kimmeridge Clay of 

 Weymouth, seems to represent an undetermined genus 

 allied to Ischyodus. 



43284. Left mandibular tooth, 0*014 in length, much 

 laterally compressed, and with an external thickening 

 immediately below the oral border. This border is 

 deeply sinuous, and the symphysis is very narrow. 

 Two outer tritors and one beak-tritor occur, each 

 being small, styliform, and laminated • but there is 

 no median tritor. Purchased, 1871. 



P. 118. To the second group of Ichthyodorulites add the follow- 

 ing :— 



Compsacanthus carinatus, J. W. Davis, Trans. Roy. Dublin Soc. 

 [2] vol. i. (1883), p. 354, pi. xlvi. fig. 10.— Lower Car- 

 boniferous Limestone ; Armagh. [Olirn Enniskillen Coll. : 

 see Introduction.] 



Tiibulacanthus sulcatus, A. Fritsch, Fauna der Gaskohle, vol. ii. 

 (1889), p. 113, pi. lxxxviii. fig. 14. — Lower Permian ; 

 Kounova, Bohemia. [Eoyal Bohemian Museum.] 



Brachiacanthus semiplanus, A. Fritsch, ibid. p. 113, pi. lxxxiii. 

 fig. 10.— Ibid. [Ibid.] 



Platy acanthus ventricosus, A. Fritsch, ibid. p. 113, pi. lxxxvi. 

 fig. 5.— Ibid. [Ibid.] 



P. 123. Some genera of the third division of Ichthyodorulites have 

 recently been associated with the lEyriacanthidge by O. 

 Jaekel, and the miscellaneous and indefinable group thus 

 formed is named Trachyacanthidse (Sitzungsb. Ges. naturf. 

 Freunde, Berlin, 1890, p. 130). 



