the smaller British Mammalia. 2G5 



so often alluded to in my former papers, in which they have 

 been treated of in detail, and to which 1 must refer those who 

 are interested in the subject. I may, however, make one or 

 two remarks, as supplemental to his. 



M. Duvernoy states the length of the intestinal canal in the 

 S. tetragonurus, compared with the length of the body, to be 

 as three to one, and rather more. In most of the specimens 

 which I have examined, I have found it nearly as four to 

 one, and in some instances even bearing a higher ratio than 

 this ; whilst the ratio of three to one more nearly accords 

 with the case of the S. Hibernicus. The relative, however, 

 as well as the absolute length of the intestinal canal, varies a 

 little in both species, according to the size of the individuaL 

 I shall here annex the actual measui'ement of this, and one 

 or two other parts, such as were observed, first, in a medium- 

 sized specimen of the S. tetragonurus, and then in an old 

 full-grown S, Hibernicus. 



S. TETRAGONURUS. " i„ehes. lines. 



Length of the head and body 2 7 



of the tail 1 9 



Greatest diameter of the distended stomach 7 



Distance from the cardiac orifice to the pylorus, being "1 „ ,^ 



the length of the pyloric gut J 



Entire length of the intestinal canal, from the pylorus \ iq q 



to the anus i 



S. Hibernicus. . , ,. 



inches, lines. 



Length of the head and body 2 2§ 



of the tail 1 5 



Greatest diameter of the distended stomach 6| 



Distance from the cardiac orifice to the pylorus 9 



Entire length of intestinal canal, as before 7 



The number of ribs, which is not mentioned by Duvernoy, 



I find to be 14 in both species, of which 7 are true and 7 



false. 



The number of vertebree was also found to be the same in 



the case of a single individual of each species, and may be 



estimated as follows : — 



Cervical 7 



Dorsal 14 



Lumbar 6 



Sacral 2 



Caudal 15 



Total 44 



