EXCRETORY ORGAX OF FRESH-WATER POLYZOA. 357 



words: — " Ceux-ci (the vibratile organs) sonf deux canaux assez courts, 

 atténués vers l'extrémité, renflés au milieu, formés, d'après Hat- 

 schek, de cellules perforées, mais où je n'ai pu distinguer, avec des 

 grossissements supérieni-s à ceux employés par cet auteur, qu'une 

 obscure division transversale, sans <|u'il m'ait été possible de constater 

 une structure cellulaire bien nel"te. Le pavillon, qui ternn'ne chaque 

 canal ressemble à un entonnoir taillé en bec de flute, fendu sur la 

 li^ne médiane sur un certain longueur et dont de bord libre serait 

 épaissi en bourrelef sur une certaine étendue et se prolongerait plus 

 loin en un lèvre délicate." As to the physiological rôle of these organs, 

 the author does not give anything definite; he only denies their service 

 as evacuatory canals for the genital products. He remarks further, 

 c<~>ncerning their function : " Les parois de ces canaux sont si minces, 

 qu'elles ne peuvent guère être regardées comme glandulaires et for- 

 mant un org-an excréteur," but later investigations have shown that 

 this is not strictly true. 



About five years later than the last paper, Haraier (1885) pub- 

 lished the results of his investigations on the anatomy and develop- 

 ment of Loxosoina. He studied the nephridium of this animal very 

 closely, and his short but precise statements have since been, in the 

 main, confirmed by Foettinger (1887), another investigator of this 

 oro-an, who two vears later tlian H armer, wnjte a valuable article on the 

 Pedicellina of Ostend. What I have been able to observe in Barentsia 

 misalciensis also agrees with the results ot" these two authors, except on 

 a few points of secondary importance. Harmer found, namely, the 

 nephridia of Lo:ro.so;;/a lying on the ventral wall of the stomach, one 

 on each side of the oesophagus, and situated near the anterior surface 

 of the body. He says: — " the proximal part consists of a small number 

 of cells, which, in opposition to Juliet's statement, I consider un- 

 doubtedly excretory in function The distal portion of the nephri- 



