4 ME. F. H. A. MARSHALL ON [Jan. 14, 



Text-fig. 1. 



y 



Genital apertures of Nejphrops norvegicus. 



Male of Nephrops norvegicus having abnormal genital apertures on each of the 



third and fourth walking-legs. 



Text-fig. 2. 



Genital apertures of Neplirops norvegicus. 



Male of Neplirops norvegicus having abnoraial genital apertures on the right third 



and right fourth walking-legs. 



In no specimen was either of the normal apertures wanting. 

 The animals were examined in batches- — the first batch, which 

 was much the largest, consisting of the stock of Norway lobsters 

 in the zoological laboratory of the University of Edinburgh, 

 obtained for the use of students during the summer session. 

 The rest were procured at various intervals of time during 

 the summer and autumn. The numerical details of these batches 

 are now given : — 



(1) Females 56 



Normal males 485 ") 



Abnormal males with arrangement B... 23"^ | 



Ditto with arrangement C 21 j I ^ , q 



D 17>63r*^ 



« » • E 1 I I 



H IJ J 



Total ... 604 



