341 



Nachdruck verboten. 



On a Tactile Organ in the Cheek of the Mole, Scalops Aquaticus. 



By James E, Ackert. 



(Contributions from the Zoological Laboratory, University of Illinois, under 



the direction of HENRY B. WARD, No. 14.) 



With 5 Figures. 



A protuberance containing vibrissae occurs in the cheek of the 

 shrew-mole, Scalops aquaticus machrinus (Rafinesque). The present 

 paper deals (1) with a comparison of the external appearance of this 

 protuberance with more or less similar structures in the cheeks of 

 white-footed mice, rats, bats, and opossums; and (2) with the inner- 

 vation of this organ in the mole. 



The Haarbälge of horses, sheep, oxen, dogs, cats, swine, rats, 

 and mice were investigated by Bonnet^ ('78), who found tactile hairs 

 in nearly all mammals, in different degrees of development, and in 

 varying numbers, on the snout, the cheeks, the lower jaw, and the 

 eyelids. The groups of tactile hairs occurring upon the cheeks of 

 many mammals were mentioned by Bonnet (p. 331), but were not 

 described by him. 



Wood (Wood and West 2, '10) briefly mentions the presence of 

 this organ in the mole. He says, "Between the eye and the ear is 

 a protuberance containing vibrissae an probably functioning as an 

 organ of touch." 



Comparison of the Protuberances in Various Mammals. 



In the animals studied the positions of these protuberances are 



identical, viz., directly between the eye and the base of the ear, and 



a little dorsocaudad of the posterior angle of the mouth. Upon each 



protuberance are three kinds of hairs: Ä, large vibrissae; 5, hairs 



1) Bonnet, Robert 1878. Studien über die Innervation der Haarbälge 

 der Haustiere. Morph. Jahrbuch. Vol. 4, pp. 329—398. 3 PI. 



2) Wood, Frank E. and West, J. A. 1910. I. On the Common Shrew- 

 Mole in Illinois. II. A Study of the Food of Moles in Illinois. Bull. 111. 

 State Lab. Nat. Hist. Vol. 9, pp. 1—22. 3 fig. 



