Browne —Fauna and Flora of Valencia Jffarhonr, Ireland. 717 



I have made rough diagrams of the canal systems of 200 

 specimens taken in Valencia Harbour in 1897, and have 

 selected twelve diagrams (figs. 1-12) to illustrate the irregular 

 arrangement of the radial canals. These specimens clearly 

 show that this species does not agree with Haeckel's definition 

 of the genus JDipleurosoma. I do not wish to make a new genus 

 for this species, especially as Boeck originally founded the genus 

 Dipleurosoma ; but Haeckel's definition must be ultimately 

 altered and D. amphithectum removed to another genus. 



j!^otes ois the Valencia SpEcniEisrs. (Plates xx., xxi.) 



Stomach. — In the majority of the specimens the stomach is longer 

 than it is wide, and the usual type is shown in fig. 3 ; but it may be 

 triangular (fig. 4), or nearly round (fig. 5), or very irregular (fig. 11). 

 In all the figures only the base of the stomach is drawn, so as not to 

 make the diagrams too complicated. The walls of the stomach meet 

 about the centre, and terminate in a mouth with foui' lips. JS'early all 

 the specimens preserved in formalin have the mouth fully expanded, 

 forming a simple ring. 



I believe that the irregularly shaped stomach is due to the outgrowth 

 of the radial canals, and to a subsequent outgrowth of the stomach 

 itself. The base of the stomach has the appearance of ground glass, 

 divided by a number of clear lines which meet about the centre. These 

 transparent lines correspond in position with some of the large canals 

 (figs. 8 and 11), and, I believe, mark the original position of the radial 

 canals. The stomach has grown outwards and taken in a part of the 

 radial canals. The enlargement, also, of the radial canals at their exit 

 from the stomach is a process connected with the growth of the stomach, 

 converting a portion of the canals into lobes of the stomach. Upon 

 this outgrowth I base my views that all the radial canals leave either 

 the stomach itself or a lobe of the stomach, and that the primary 

 canals, in the young Medusa, are not subsequently branched, as in the 

 figure given by Haeckel of J). amphitJiectum. 



Radial Canal System. — At present I have no clue to the num- 

 ber and the position of radial canals in tbe earliest free-swimming 

 stage. All the specimens belonged either to intermediate stages or to 

 the adult form, mostly to the latter. The radial canal system may 

 conveniently be divided into three types, which are not absolutely 

 distinct, as a blending of the types occurs in some specimens. 



(a) A roundish stomach, with four or more canals about equal 

 distances apart. 



3 D 2 



