Rev. T. R. R. Stebbing on the Genus Bathyporeia. 75 



in the figure of B. pllosa^ very long in that of B. pdagica^ 

 and of intermediate size in that of B. liohertaoni. But in the 

 order Amphipoda, as with the facets of the eyes, so with the 

 articuli of the lash of the antenna?, an increase takes place 

 with advancing age. This part of the animal will not, there- 

 fore, of itself suffice for the establishment of a specific distinc- 

 tion. Still the figure with the lash of intermediate size has a 

 character not attributed to either of the other forms. The 

 distal end of each articulus of the flagellum is surmounted by 

 an ornament in the shape of an elongated horse-shoe, to which 

 Mr. Stimpson has given the name '"'' calceola^'' informing Messrs. 

 Bate and Westwood that it is a character of the male sex. 

 In their description of Lysianassa longicornis these authors 

 express the opinion that the " calceolte " have the power of in- 

 creasing the sense of smell to a more acute degree. In de- 

 scribing Bathyporeia llohertsoni they mention the additional 

 circumstance that in the upper antennae each articulus bears 

 '' a short auditory cilium of an oval form." Fritz Miiller 

 mentions, in his ' Facts for Darwin ' (Translation by Dallas, 

 p. 20), that he considers these " auditory cilia " of the upper 

 antennae to be olfactory organs, fortifying his opinion by the 

 fact of their stronger development in the males than in the 

 females of certain species, as in other cases male animals are 

 not unfrequeutly guided by the scent in pursuit of the females. 

 Whether Bathyporeia appreciates scent and sound by the 

 lower and upper pairs of antenna? respectively or vice versd^ 

 or whether to each or either of these purposes it applies both 

 of them or neither, is a question for nice and careful experi- 

 ment. This much, however, is certain, that the " calceolae," 

 whatever their use may be, were present in those specimens 

 which had the antennae about as long as the animal itself, 

 thus bringing B. pelagica one step nearer to B. Rohertsoni. 

 Between the short flagellum and the long one the difference is 

 considerable, the former having only some seven or eight articu- 

 lations, while in the latter I counted thirty-two. It should also 

 be stated that on none of the short flagella did I observe the 

 slipper-shaped appendages, although the specimens of this form 

 were considerably more numerous than those of the other two. 

 On the other hand, I took the form that has short antennje 

 with the young upon it, establishing the point that this is a 

 female form, though leaving it an open question whether its 

 mate in all respects resembles it. The young just born had 

 a strong family likeness to their mother. There did not seem 

 to be any long antennje among them ; nor were they to be 

 expected. 



Of the other parts of the animal one description will equally 



