VII 



MOLLUSC A GENITAL ORGANS 



243 



same arm that is thus transformed. In the Octopoda, as a rule, it is the third 

 on the right side, but in the Octopodan subgenus Scceurgus and in Argonauta 



FIG. 200. Male of Argonauta argo (after H. Miiller). (Female, Figs. 35, 36, pp. 24, 25.) A, 

 With the hectocotylised arm enclosed in the sac (d). B, with the arm free, a, Funnel ; 5, edge of 

 the mantle fold ; c, left eye ; d, sac ; di, hectocotylised arm ; e, mouth. 



it is the third on the left. In the Decapoda the hectocotylised arm is generally 

 the fourth on the left, but in the genus Enoploteuthis it may be the fourth on 



FIG. 201. Hectocotylus of Philonexis 

 (Octopus) carenae (after Leuckart). a, 

 Spennatophoral pouch ; b, seminal vesicle ; 

 c, efferent duct of the same ; d, appendage 

 = remains of the penis sac ; e, penis ; /, 

 sucker. 



the right, or even in one and the same species of Ommastrephes, it is sometimes 

 the fourth on the left and sometimes the fourth on the right. In Sepiola and 



