SEA-FISHERIES LABORATORY. 383 



XXth Annual Eeport (1911) : " In our district 

 " B. sinensis is of more elongated form than is shown in 

 " Ostenfeld's figures. Most of our specimens of 

 " B. sinensis are very distinct and easily distinguishable 

 " from the mobiliensis-regia group by the shape and the 

 " position of the spines, but we have found one or two 

 " specimens during this last year where one end of the 

 " cell bore the characters of sinensis, while the other had 

 " the appearance of mobiliensis. Until, however, we get 

 " further specimens we do not propose to base any 

 " opinion as to the species upon this possibly abnormal 

 " form. We are watching the fresh material of 

 " B. sinensis carefully in the present year (1912), and 

 " may return to the subject in our next report." We 

 are now carrying out that intention. 



The change in the stability of Biddulphia sinensis 

 became more marked in the Bay gatherings taken in the 

 early spring of 1912, and again in the Bay gatherings 

 taken in December. 



The appearance of the abnormal forms is shown by 

 figs. 5, 7, 8, 9, 10, 12, 14 and 15 on the Plate. All 

 these figures show clearly that one end of the cell is a 

 Biddulphia sinensis, while the other end shows a decided 

 approach to the appearance of Biddulphia mobiliensis. 

 The spines have migrated away from the base of the 

 continuation processes of the shell to nearer the centre. 

 The concavity between the spines which is distinctly 

 visible at the sinensis end has become almost obliterated 

 at the mobiliensis end by the migration of the spines. 

 The continuation processes have also suffered to some 

 extent. They have disappeared entirely in figs. 7 and 9, 

 and only one is left in figs. 8, 10, 12, 14 and 15. Most 

 of the figures show the cell in the process of division. In 

 some cases one of the daughter cells will become a typical 



