Dr. A. Giinther on the Dentition of Herpeton tentaculatum. 195 



are several series of tentacles on the posterior side of the pec- 

 toral fins. D. 3/3/12. A. 10. C. 8. P. 23. V. 1/5. 



EXPLANATION OF PLATE X. 



Figs. C, D. Lophius piseatorius, young; taken from specimens when de- 

 pressed ; coijied from Diiben and Koren : C, lateral view ; D, view 

 from above. 



Fig. E. Lophius piseatorius, young ; taken from a compressed specimen. 



XXII. — On the Dentition q/" Herpeton tentaculatum. 

 By Dr. Albert Gunther. 



Exactly a year ago, when describing and figuring Siamese 

 specimens of Herpeton tentaculatum, Lacep., I stated that " all 

 the teeth are of equal size, and not one is grooved ^." When, 

 therefore, I found that Prof. Jan, in the first part of his * Icono- 

 graphy,' just published, which he has kindly sent me, represents 

 the two posterior maxillary teeth as twice the size of the anterior 

 ones, and both of them distinctly grooved, I was induced to re- 

 examine the specimens in the British Museum, to test the cor- 

 rectness of either of the two contradictory assertions. For this 

 purpose I have removed the mucous membrane from the teeth 

 of both specimens on both sides, thus obtaining four views of the 

 dentition, which fully confirm the correctness of my observa- 

 tion. There is not the slightest trace of a groove on either of 

 these teeth ; and when Prof. Jan represents them with a groove, 

 he either does it on the sole authority of Dumeril, who suggests 

 that Herpeton might have a grooved tooth, like the other snakes 

 of the family of Platijrhiniens, or he has been misled by the ac- 

 cidental juxtaposition of a second tooth destined to replace that 

 in function : in this case, the two teeth which are standing 

 close together may appear as a single tooth with a longitudinal 

 groove. Yet Prof. Jan represents two teeth, each with a groove ! 



Now, with regard to the size, I admit that, strictly speaking, 

 the posterior tooth is larger than the anterior ones ; but it is, 

 comparatively, not larger than in species of Herpetodryas or 

 other so-called Isodontes, and to call that tooth twice as large 

 as the anterior ones would be a great exaggeration as far as re- 

 gards the specimens in the British Museum. We cannot assume 

 that the dentition is modified in different ages of this snake, as 

 one of the specimens examined is considerably larger, the other 

 much smaller than that in the Milan Museum. 



These observations have been considered necessary, inasmuch 

 as many herpetologists will be guided by the dentition in assign- 

 ing to this snake its place in the system. 



• Proc. Zool. Soc. Feb. 14, 1860. 



