MORPHOLOGY OF MELIBE 559 



of the renal syrinx to the ureter and pericardium. Dealing 

 with a number of types : P h y 1 1 i r o e , A c u r a , R i z z o 1 i a 

 australis, Bornella, Tritonia challengeriana, 

 and Marionia (pp. 8, 8, 80, 41, 47, and 51, respectively), 

 he only describes the shape and size and a few of its finer 

 structures, and also that it opens into the pericardium on the 

 one hand and the ureter on the other. For the holohepatic 

 form, Chro mod oris stria stella, he says: the renal 

 syrinx is bulb-shaped of 0-75 mm. greatest diameter ; the folds 

 of the interior can easily be seen from the outside ; the ciliated 

 cells are as usual. The duct of the renal syrinx is about 

 1-5 mm. long, opening into the chamber ; in the anterior are 

 the usual villi and papillary outgrowths. 



Pelseneer (1893 : 458) : ' Je crois que c'est le plus anterieur 

 ou ventral qu'on doit considerer comme tel : les Nudibranches 

 les plus voisins de Ely si a (Hermaea, Cyerce) m'ont en 

 effet montre I'orifice reno-pericardique a la meme place, 

 ventralement et a gauche. Les autres conduits seraient 

 secondaires ou cenogenetiques et resulteraient vraisemblable- 

 ment de la multiplicite des points de contact entre le pericarde 

 et le rein, celui-ci entourant plus ou moins le premier.' 



Stempell (1 899 : 1 42) finds for S o 1 e m y a t o g a t a , Poli : 

 * Von histologischem Interesse ist zunachst die Beschaffenheit 

 der Nierenspitzen. Dieselben besitzen namlich nicht wie 

 diejenigen der Nuculiden ein flaches, mit langen Geisseln 

 besetztes Epithel, sondern ein gewohnliches mittelhohes 

 Cylinderepithel, welches nur massig lange Cilien tragt.' 



And MacFarland (1912 : 527), for Dirona picta, writes : 

 ' The reno-pericardial opening is fomid in the renal syrinx, 

 a conspicuous pyriform body situated midway of the animal's 

 length, upoji the right dorsal surface of the visceral complex. 

 It communicates below with the pericardial cavity, opening 

 through the floor of the right side. Its lumen is divided by 

 numerous folds of the wall, many of which in turn bear 

 secondary folds. The complicated opening thus formed is 

 lined in its upper portion by high columnar cells, bearing very 

 long cilia, which are directed downward.' 



