0. P. Hay — Notes on species of Ichthyodectes. 225 



Aet. XXIII. — Notes on species of Ichthyodectes, including the 

 new species I cruentus, and on the related and herein estab- 

 lished genus Gillicus / by O. P. Hat, Ph.D. 



Ichthyodectes hamatus Cope. 



-Cope, 1872, Proc. Amer. Philos. Soc. vol. xii, p. 340; 1875, Cretaceous Verte- 

 brates, p. 209, pi. xlvi, figs. 5, 5a. 



Of this species I possess two nearly complete dentaries. 

 The tooth-line has a length of 100 mm . One clentary has 27 

 teeth ; the others 28. Prof. Cope states that the mandibular 

 in his possession displayed 25 teeth, but it is quite probable 

 that there is considerable individual variation in the number. 

 The form of the jaw and the presence of the upturned sym- 

 physial hook indicates that my specimens belong to Cope's 

 /. hamahts. The teeth are closely arranged and they show a 

 peculiarity of form and setting that has not been noticed by 

 Prof. Cope. This peculiarity is found in the fact that the 

 teetli are elliptical in section, with the long axis of the section 

 placed obliquely to the axis of the tooth-line, its outer end 

 being thrown forward. The longer axis will average close to 

 gmm j n l en gth 5 the shorter about 3 mm . The alveolar border is 

 somewhat scooped out on the inner side just behind the hook, 

 aud just here the teeth are smaller than elsewhere. On the 

 hook itself there are two teeth. The enamel is smooth. 



Ichthyodectes cruentus sp. nov. 

 Figs. 1 and 3. 



This supposed new species is founded primarily on a some- 

 what imperfect left maxilla which came from Butte Creek 



l. 



Canyon region in western Kansas. I have also a nearly per- 

 fect dentary and portions of one or two others which apparently 

 belong to the same species. Of the maxilla, the anterior 

 extremity, including the anterior condyle, is wanting, and also 

 the distal extremity (fig. 1 X f). 



