Regeneration in Gunda ulvse. 



35& 



. 5. The working mechanism of the latter is clearly indicated by remarkable 

 phenomena of the storage and subsequent disappearance of starch in the 

 andrcecial region ; while similar phenomena of starch storage and depletion 

 in the gyncecial region illustrate the progression from a simple " drop- 

 mechanism" to a copious exudation of sugar and the adaptation of the 

 structure to entomophily. 



6. The nectary region of the ovule is retained by the gyncecium of the 

 sterile flower for the same function, and vascular bundles supplying fluid for 

 this purpose are not necessarily vestigial. Entomophily is thus probably 

 antecedent to dicliny. 



The Influence of the Position of the Cut upon Regeneration in 



Gunda ulvse. 



By Dorothy Jordan Lloyd, B.Sc, Bathurst Student of Newnham College, 



Cambridge. 



(Communicated by J. Stanley Gardiner, F.B.S. Beceived January 14, — 

 Bead February 19, 1914.) 



I. Introduction. 



In 1899 Hallez (4) made the generalisation that the most important 

 difference between the regeneration in Triclad and Folyclad Flanarians was 

 to be found in the fact that fragments of the former could regenerate in the 

 absence of the central nervous system, whilst in the latter some portion of 

 the cerebral ganglia must be present in order for regeneration to take place. 

 Child (1) has confirmed the fact that the presence of cerebral ganglia, or at 

 least intact nerve roots, is necessary for regeneration of the anterior end and 

 sense organs of Folyclads. The experimental work by the same and other 

 authors has also established that, among Triclads, the genus Planaria is able 

 to regenerate completely in the absence of cerebral ganglia. The following 

 notes, however, show that in another Triclad genus, namely, Gunda, anterior 

 regeneration is, as in Polyclads, dependent on the presence of the central 

 nervous system. 



The experiments described below were carried out in the Plymouth 

 Laboratory of the Marine Biological Association during the spring of 1913. 

 I am greatly indebted to the director and staff of the laboratory for constant 

 kindness during the course of my work at Plymouth. I also stand under 



