136 



vascular system of this species and of the Brada-sitocuncns, it only 

 may be mentioned, that, according to Quatre f ages, in his C/ilo- 

 raewa-species the heart results from the union of two large vessels 

 (his troncs dorsaux), situated along the sides of the stomach, from 

 which they receive numerous small branches. It is obvious that 

 Quatrefages found here nothing resembling a blood-sinus in the 

 ■walls of the intestine, »une circulation lacunaire« as he calls it after- 

 wards (p. GO). Further Mr. Cunningham puts the question whether 

 the vessel, mentioned above, really represents the typical dorsal vessel. 

 Examining namely a Trophonia piumosa he found »a thin vessel runn- 

 iu"- in the dorsal median line on the inner surface of the body Avail, 

 unaffected by the convolutions of the intestine, receiving metameri- 

 cally arranged transverse vessels from the walls of the latter, and open- 

 \\\<y into the dorsal side of the heart at a point a third of its length from 

 the hinder end«. He believes this vessel to be the real dorsal vessel, 

 and presumes that only the anterior portion of the heart of the Chlo- 

 raemidae belongs to the dorsal vessel of other Annelida, whereas its 

 posterior portion represents a vessel, through which the blood is con- 

 ducted from the walls of the intestine to the dorsal vessel. 



I must begin to say, that the existence of this vessel was not un- 

 known to me ; not only I observed it in the 5rao?a-species 2, but Rathk e 

 already described this vessel in 1812 in Trophoma piumosa"^. Mr. 

 Cunningham appears to have overlooked the researches of this 

 eminent investigator, notwithstanding I fixed the attention on them 

 in my Note. Mr. Maurice Jaquet* also recognised in Siphonostoma 

 diplochaitos the presence of two contractile vessels running in the dorsal 

 median line of the body and opening into the heart quite near to each 

 other. He also puts the question Avhether these latter vessels or the 

 so-called heart must be considered to be the homologue of the dorsal 

 vessel of other Annelids, without arriving at a definitive conclusion. 



It is probable enough that Mr. Cunningham's interpretation is 

 right, and that the thin dorsal vessel of the Chloraemidae may represent 



2 Press of other work hitherto prevented me from publisliing a more detailed 

 account of my investigations on this matter. 



3 Beiträge z. vergi. Anat. u. Physiol. IV. Siphonosfnina plumosuin. p. 8S. 



* Ilcchcrchcs sur le système vasculaire des Annélides. Mittheil, aus der Zoolog. 

 Station zu Neapel. VI. Bd. Tliis author makes no reference at all to my views on 

 the vascular system of the Chloraemidae. Mr. Bourne already pointed out his care- 

 less manner of treating the previous literature on the vascular system of the Hiru- 

 ilinca fZool. Anz. No. 260 . Mr. Jaqu ct did the same in relation to the literature on 

 the anatomy of Lunibricus ; had he been acquainted with the researches of his pre- 

 decessors, his chapter on the vascular system of the Earthworm had better been un- 

 written, for however skilfull his injections may be, our knowledge of this matter is 

 little augmented by them. 



