524 



PROCEEDINGS OF TEE NATIONAL MUSEUM. 



VOL. XXVIII. 



eg 



s.r. 



maxillipeds. Their judgment of the course taken b}^ the several nerves 

 may well have been biased by these mistakes. The present author 

 has had no opportunity of verifying or disproving their statements by 

 an examination of the same species. 



The similarity in the structure and use 

 of the appendages of all the genera here 

 considered renders it probable that their 

 innervation is practically the same, differ- 

 ing only in minor details. 



REPRODUCTIVE ORGANS. 



These consist in the female of a pair of 

 ovaries, a long, more or less convoluted 

 oviduct connected with each, a pair of 

 semen receptacles, glands for secreting the 

 material of the external egg cases and 

 these cases themselves (fig. 29). 



The ovaries (o) are large oval or kidney- 

 shaped bodies situated on either side of 

 the anterior portion of the dorsal surface 

 of the stomach. When fully developed 

 they extend from the first swimming legs 

 to the base of the second maxilla? and can 

 be plainty seen through the carapace in 

 dorsal view. Each gives off an oviduct 

 (o. d.) from the ventral surface at the an- 

 terior margin (fig. 30). This duct runs 

 backward in nearty a straight line through 

 the thoracic area, the free segment, and into 

 the genital segment. As soon as it enters 

 the latter it increases quickly in size and also 

 becomes convoluted. The number and ar- 

 rangement of the convolutions vary consid- 

 erably in the different species as well as the 

 genera, as may be seen by consulting figures. 

 In general, the convolutions attain their 

 maximum number and size just before the 

 extrusion of the external egg cases, and as 

 soon as the latter are fully formed the 

 oviduct has become nearly straight. This condition is retained at 

 least for some time subsequent to the hatching of the eggs and the 

 throwing off of the egg tubes, since the adult females are often found 

 in the condition shown in fig. 31. 



On the ventral surface of the convolutions can be found an oblong, 

 nearly transparent gland, closed at the anterior end, and at the poste- 



Fig. 29.— Female reproductive 

 organs of caligus bonito. 

 (Drawn by Emerton.) c. g., 

 cement gland; e. c, external 

 egg cases; o, ovary; o. d., ovi- 

 duct; s. r., SEMEN RECEPTACLE. 



