Biiilsh Forms of K\)0'\(i\\n\s. 133 



II. Note on the Glans Penis of Apode^ws. 



Prof. L. ^leliely* has recently obtained good differential 

 cliaracters from the structure of the glans penis in Sicisla, 

 and he suggests tliat in many dithcult groups of" rodents 

 {e. g., ^licrotinie) the g(;nitalia will be fouiul to be of great 

 systematic imp(jrtance. Unfortunately many of the spirit- 

 specimens of Apodemus before me arc too young to yield 

 satisfactory characters, but nevertheless they are of much 

 interest. 



Two types of penis are fouiul iu these specimens. In one 

 the oi-gan tapers distally below the bend ; the glans is com- 

 plex, with a large papilla centralis \, distinct p. laterales, a 

 more or less evident rudiment of adtjrsal inner annular fold, 

 and a large frequently trifid p. liagualis. P. centralis is lofty 

 and pi'ojects noticeably beyond the margin^ or outer aunular 

 fold, of the glans ; usually it extends from the centre of the 

 glans to the dorsal border, in which case^ viewed from below, 

 it is diainoud-shaped, and prol)ably consists of bath j^- (^'^>^- 

 tralis and p. dorsalts, which have fused ; I have not seen 

 the latter element distinct in this genus ; le?s fre([uently 

 p. centralis is small and separated from the outer margin of 

 the glans by an inner dorsal annular fold which connects 

 the two p. laterales. This complex type of glans was observed 

 in: — A. hebridcnsis, 13. M. 11. 1. 3. 415, Barra ; A. sylvati- 

 cus, 98. 9. 29. 3-0, Alderney; 81. 1. 11. 1, Bishopstone, 

 Hereford ; A. s. callipides, 91. 1. 1. 10-12, Villalba, N.W. 

 Spain ; 94. 3. 19 1, Coruna ; A s. " islandicus ," 0. 8. 12. 1-3, 

 Iceland ; A. ayrarius, 55. 11. 6. 3, Brants. In these speci- 

 mens the length of the penis, from bend to end, varied 

 between 37 and 53 mm., and was in most cases between 

 4 and 4"5 mm. ; its breadth ranged between 1*5 and ,l"Z mm. ; 

 the testes in all but one case were small (from 4 to 7 mm. 

 in diameter) ; iu one of the Villalba mice the testis was 

 1 1 mm. in diameter. 



In the second type the penis is cylindrical below the bend 

 and considerably larger; the glans is much simpler, the only 

 structures visible being a large dorsal inner annular fold 

 and two lateral ventral papiike of large size, each of which 

 is sometimes fused dorsally with the inner annular fold ; 

 these structures are low' and do not project noticeably beyond 

 the level of the outer margin of the glans, which appears 



* L. V. Mehely, Ann. Mus. Nat. Ilungarici, xi. 1913, p. 2ul. 

 t The names used by Tullberg. 



