380 



its terminal sac contained the white thread (fouet) , a part of the 

 male generative organs. 



There are, then, male Argonauts, but so very small that they 

 have been mistaken for embryos still carrying the umbilical vesi- 

 cle ; this supposed vesicle of the embryo was one of the trans- 

 formed arms of the adult animal, containing the so-called Hec- 

 tocotylus. (Figures of the adult male Argonaut were exhibited, 

 of the natural size, not quite an inch in length, while the adult 

 female is from six to eight inches long.) H. Muller, who first 

 discovered the male Argonaut, says that it has no shell ; neither 

 has the female, according to him, wdien of the same small size ; 

 the arms are all pointed, not having the palmated appendages of 

 the female.* 



Belovv the venous appendages are the male organs of genera- 

 tion, consisting of a testicle, vas deferens, a receptacle in the 

 shape of a bottle, and an ejaculatory duct by which the sperma- 

 tophore is expelled during copulation. The greatly developed 

 arm, above alluded to, has for its axis a cylindrical muscular 

 tube, continued beyond the suckers into a long thread-like body 

 {fouet), usually concealed in the terminal sac ; in the middle is a 

 bloodvessel and a series of nervous ganglia, mistaken by Koel- 

 liker for the intestine and its contents ; at the base of the arm 

 is a sac in which the seminal apparatus is contained. 



A figure of a Hectocotylus, or one of these detached arms of 

 the male Cephalopod, was exhibited, in which was seen the 

 pedicle on which it is implanted and from which it is very readily 

 detached ; oval below, more pointed and truncated above, ter- 

 minating in a sac containing the fouet, or in this organ unrolled 

 and as long as the arm ; it has two rows of suckers. The sepa- 

 ration of these arms takes place without laceration, naturally, 

 and the pedicle which remains undoubtedly reproduces the arm, 

 as in the case of the deciduous horns of Ruminants. The sac 



* [In the A. genlciilata, Gould, the shell is unknown; it is stated (op. cit.) 

 " that there was no impression on its surface answering to the folds of a shell, 

 so that it had not very recently, if ever, occupied one." M. Rang is of opinion 

 (see Ferussac and D'Orbigny) that the shell is formed by the/e/«a/e Argonaut 

 for the protection of her eggs ; and that, perhaps, the male has no shell — this 

 point requires further investigation.] 



