RED VASCULAR FLUID OF THE EARTHWORM. 69 



peut en citer d'autres exemples. Dans ce memoire, ou trouvera 

 des corpuscles sanguius proprement dits, decrits chez les Ophe- 

 lies, chez les Cirratuliens, chez les Staurocdphales." 



The same zoologist, however, in his classical * Histologische 

 Untersuchungen iiber den Regenwurm,' published in 1869, ex- 

 plicitly affirms the absence of such corpuscles from the vascular 

 fluid of the Earthworm. Speaking of the remarkable spherical 

 dilatations of the blood-vessels which occur on the walls of the 

 segmental organs or nephridia and in other parts, he writes what 

 is here translated, "The structure of these dilatations of the 

 vessels is of such a nature that it is not possible to regard them 

 as accidental. Gegenbaur, moreover, says that he has always seen 

 them filled with a red coagulum enclosing blood-corpuscles. 

 Lankester also saw a granular matter within them. In point of 

 fact I find in them constantly a quantity of nuclei, which in all 

 probability are derived from the division of an ordinary nucleus 

 of the vessel's wall. Such nuclei I am unable to regard with 

 Gegenbaur as blood-corpuscles, ,s/«cg it is a to ell-known fact that 

 blood- corpuscles are absent from the Earthworm^' 



The statement made by Gegenbaur, and here referred to, 

 occurs in his article " Ueber die sogenannten Respirations-organe 

 des Hegenwurms " in the 'Zeitsch. fur Wiss. Zoologie,' 1852,° 

 vol. iv, p. £27. He says " Das Lumen dieser Anschwellungen 

 stellte sich mir fast immer mit einem rothen, Blutkorperchen 

 einschliessenden coagulum ausgefuUt dar." The blood-corpus- 

 cles thus recorde i by Gegenbaur are those only of the vascular 

 dilatations which ditfer in character from those which 1 shall 

 describe below, and though clearly entitled to rank as blood- 

 corpuscks or corpuscles of the red vascular system, are peculiar 

 and apparently confined to these dilatations. 



By various writers the absence of corpuscles from the vascular 

 fluid of the Cheetopoda has been considered a sufficient objection 

 to the use of the word ' blood ' in reference to that fluid, and it 

 has been spoken of as a ' pseud-hsemal,' as distinguished from 

 a true MisemaP fluid. A variety of views have also been put 

 forward at diff'erent times as to the relationships of this fluid 

 and the vessel which contain it, and of the perienteric or peri- 

 toneal corpusculated fluid, to the ' blood ' of MoUusca, of Arthro- 

 poda and of Vertebrata. Gegenbaur, in his ' Grundztige der 

 vergleichenden Anatomie,"* 2nd edition, 1870, p. 231, in de- 

 scribing the existence of a fluid contained in a distinct vascular 

 system, and of another fluid occupying the body-cavity in the 

 Nemertine worms says, "We shall speak of this latter as chylus, 

 of that contained in the closed vascular system as blood." 

 Further on (p. 233) he applies the same nomenclature to the 

 similar fluids of the Chsetopoda, with which the somewhat dif- 



