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ABSTRACTS OF MEMOIRS 



RECORDING WORK DONE AT THE PLYMOUTH LABORATORY 



The Influence of the Position of the Cut upon Regeneration in 

 Gunda uluce. By Dorothy Jordan Lloyd, B.Sc. (Proc. Roy. 

 Soc, B, Vol. XXVII, 1914.) 



In 1889 Hallez published a paper in the Comptes Rendus in which he 

 stated that any fragment from a Triclad could regenerate completely 

 while from a Polyclad, only those fragments could do so which contained 

 a portion of the central nervous system. The paper quoted above on the 

 regeneration of Gunda idva', a marine Triclad common at Plymouth, 

 shows that this generalization is not of universal application, since in 

 G. ulvce regeneration of the anterior end is found to be dependent, as in 

 Polyclad, on the presence of the central nervous system. 



Posterior, anterior, and lateral regeneration are considered separately. 

 Posterior regeneration, i.e. regeneration of any structure lying behind the 

 brain, is found to take place equally well in the presence or absence of 

 the cerebral ganglia. Lateral regeneration, in order to be complete, 

 requires the presence of one intact ganglion. If only part of a ganglion 

 is present, heads regenerate but are abnormal. If both ganglia are 

 absent lateral regeneration only takes place behind the level of the 

 ganglia. Anterior regeneration never occurs except in the presence of at 

 least two- thirds of both ganglia. 



The paper also records the formation of heteromorphic heads from 



short head-pieces of G. idvce in which the cut has passed transversely 



across both ganglia. 



D. J. L. 



KEW SERIES. — VOL. X. NO. 3. OCTOBEK, 1914. 2 K 



