490 THE BLOOD-CORPUSCLES OF THE ANNELIDES. 



homologies of lymphatic or of blood-vessels, these vessels have 

 recently been shown by Professor Hoffmann ( { Niederland Archiv 

 fur Zoologie,' Bd. iv. i, p. 9, 1877) to possess small round stomata 

 in their walls. It is to be hoped that the question may shortly be 

 set at rest by some anatomist to whom Branchiobclella is available 

 in the fresh state, a state in which it is not very easy to transport 

 it to any great distance. 



Professor Lankester says : — { A glance at Dorner's excellent 

 memoir on Branchiobclella would, however, suffice to satisfy a con- 

 scientious bookmaker that the vascular fluid of Branchiobdella has 

 not yet been shown to contain corpuscles/ I was not acquainted 

 with Dr. Dorner's memoir till Professor Lankester drew my atten- 

 tion to it in this article ; since that I have not merely glanced at 

 it, but studied it carefully. My study, however, of this memoir, 

 combined with that of others treating of the same subject, has not 

 sufficed to satisfy me that the blood of Branchiobclella does not con- 

 tain corpuscles. Indeed the one single passage relating to the 

 interior calibre of the blood-vessels which I have been able to find 

 in this memoir appears to me to point at least to the exactly oppo- 

 site conclusion. This passage runs thus (p. 499) : — ' Eigenthumlieh 

 f iir das Gefass-system ist noch eine Anzahl hinter einander liegender 

 Korner, welche der Innenwand anliegen.' For the presence of such 

 granular bodies in such a situation is, to me at least, intelligible 

 only on the hypothesis of their forming blood, and, from the 

 analogy of such Annelides as Cirratulus, corpusculated blood for the 

 contents of the vessel which they bestud 1 . Anyhow, Dorner's 



1 Keferstein (Midler's 'Archiv,' 1863, p. 509) speaks of three stripes of finely 

 granular pigment as lying upon the inner wall of the dorsal vessel of Branchiobdella, 

 such as many other Annelides, e. g. Cirratulus filiformis, previously described^ by him 

 ('Zeitsch. Wiss. Zool.' 1862, p. 123), possess. Similar stripes are figured by Claparede 

 (pi. xxiii. fig. 3. B, p. 268), ' Les Annelides Che'topodes du Golfe de Naples,' from 

 Audouinia filigera, and are stated by him (p. 265) to exist similarly placed either 

 between the muscular coat of the vessels and the tunica intima, or in the substance of 

 this last in Cirratulus chrysoderma. Both these animals have corpusculated blood, 

 and it is difficult to think that the suspended granules, which, according to Selenka 

 ('Niederland Arch, fur Zoologie,' Bd. ii. 1874-75, p. 34), give the blood of Aphrodite 

 aculeata its yellow tinge, do not come from some similar source. ' Blutbereitende 

 organe ' of a very different morphology, but from homologous situations, are figured 

 for us by Kupffer as the so-called ' valves ' in the dorsal vessel of Piscicola (' Zeit- 

 schrift fur Wiss. Zool.' xiv. pi. xxix. A, fig. 3, p. 342), and by Leydig, from the 

 homologous locality in the oligochaetous Phreoryctes menkeanus (' Archiv fur Mikro- 

 scop. Anatom.' i. 1865). The proliferation of the large cells, figured by these two 



