66 ANATOMY AND PHYSIOLOGY OF SALPA AND PYROSOMA 



culer dans son interieur," apparently mistaking the ciliary motion 

 for a circulation. 



Meyen calls it the " Respirations-ring," and says that it is a respira- 

 tory organ. He first described the cilia, but denies the existence of 

 any aperture leading into the organ. 



In 5. mucronata, not perceiving that he has to do with the very 

 same organ under a different form, he describes the " ciliated sac " as 

 a testis. The languet he calls simply " Haken." 



Eschricht gives it and the languet together, the name of " das lang- 

 liche organ," and considers it as a tactile organ analogous to the 

 pulps of bivalves. He rightly describes the nervous cords connecting 

 it with the ganglion. 



Sars confirms Eschricht's view, and considers the organ as analogous 

 to the tentacles of the Ascidians, which, however, cannot be the case, 

 as in many Ascidians (e.g. Clavelind) the tentacles and the " languets " 

 co-exist.^ 



M. Milne-Edwards figures the " ciliated fossa " as the " fossette 

 prebranchiale " in the plates of the last (commemorative) edition of 

 Cuvier's " Regne Animal." 



74. The Structure of the Heart. — Eschricht and Sars describe the 

 heart to be composed of a series of vesicles, which is certainly a 

 mistake, arising from the fact that the heart always presents two or 

 three constrictions, so as to appear almost moniliform. 



75. Tubular System. — This is figured by MM. Quoy and Gaimard 

 (pi. 88, fig. 12) in Salpa pinnata, under the name of " vaisseaux 

 mesenteriques." Is it to this structure to which M. Krohn refers, 

 when he says that " the meshes or lamellae of the elaeoblast are 

 traversed by numerous vessels opening into two trunks, which 

 apparently form the attachment between this organ and the vis- 

 ceral nucleus ? " 



Perhaps also it is to this system that Eschricht refers when he 

 speaks of the intestine as beset with " stalked granules." 



76. The GeDimiferous Tube. — Cuvier, Savigny, Chamisso, and Quoy 

 and Gaimard consider this structure as more or less partaking of the 

 nature of an ovary. 



Meyen mistakes it for a liver in Salpa democratica. Eschricht de- 

 scribes the process of development of the young from the gemmi- 

 ferous tube and their connection with it very carefully ; but he does 

 not seem to consider it as mere gemmation. 



He calls the organ " Keim-rohre," germ-tube, and considers it as a 



' In the Cynthia examined by the author (see note (65)), the " ciliated sac " was seated 

 npon a tubercle, but there was no " languet." 



