THE ANNALS 



AND 



MAGAZINE OF NATUKAL HISTOKY. 



[SEVENTH SERIES.] 

 No. 15. MARCH 1899. 



XXXI. — Note on the Sexual Characters of 'Ligia oceanica. By 

 Charles Chilton, M.A., D.Sc, M.B., CM., F.L.S., 



Research Fellow, Edinburgh University. 



[Plate VIII.] 



While investigating some Australasian species of Ligia 

 recently I found that in two of the species there were well- 

 marked differences between the male and the female in the 

 character of the anterior appendages of the pergeon. It is 

 probable that such differences are fairly common in the 

 Ligiidte, though in consequence of the general uniformity of 

 the perseonal appendages in this family, and of the fact that 

 they are largely concealed beneath the body and have not 

 been hitherto much used in specific descriptions, these differ- 

 ences are not very prominent and may be readily overlooked. 

 For the purpose of comparison I examined specimens of 

 Ligia oceanica, and found that there are similar differences in 

 this species also, both in the anterior perseopoda and, to a 

 less degree, in the antenna; ; and as I cannot find that anyone 

 lias drawn special attention to these sexual differences in this 

 species, I now briefly describe them. 



Bate and Westwood say : — " The male is much larger than 

 Ann. & Mag. N. Hist. Ser. 7. Vol. iii. 15 



