RED VASCULAR FLUFD OF THE EARTHWORM. 71 



gical (lefiniiioa of the term blood. He says, '' In a few annelidsj 

 again {S//U'idea aniiaia, the Ophelia:, the Clrratid'ula, and the 

 Staurocephali and Branchiobdella) , the so-called pseud-hseinal 

 system contains corpusculated blood, and communicates with the 

 perivisceral cavity, so as to form a lacunar circulation." At first 

 sight this passage would appear to be based upon the statements 

 of Claparede,' above quoted, with the omission of the important 

 case of Terebella and the addition of Branchiobdella. So far as 

 the fact of the presence of corpuscles is concerned, this appears 

 probable enough. 



The entirely original introduction of Branchiobdella into 

 the list of Aunulata with corpusculated "pseud-haemal fluid" 

 is difficult to explain, since from what follows it seems un- 

 likely that Dr. George Rolleston had made himself acquainted 

 by actual observation with any of the genera to which he alludes. 

 On page 238 of the second edition of Gegenbaur's ' Grundzuge' 

 a somewhat awkwardly introduced reference to Dorner's paper 

 on Branchiobdella might lead an unwary reader to suppose that 

 the statements there given on the authority of Kupffer and Leydig, 

 with reference to the proliferation of blood-corpuscles from 

 the valves of the vessels in other leeches (Piscicola and Clepsine), 

 have reference to Branchiobdella, which they have not. A 

 glance at Dorner^s excellent memoir on Branchiobdella would, 

 however, suffice to satisfy a conscientious bookmaker that the 

 vascular fluid of Branchiobdella has not yet been shown to con- 

 tain corpuscles, and that it notoriously ditiers from the vas- 

 cular fluid of true leeches, in that it most certainly does not " com- 

 municate with the perivisceral cavity, so as to form a lacunar 

 circulation." The introduction of Branchiobdella into the list 



1 The observal ion of corpuscles in tlie blood of Syllidia armala is due to M. 

 de Quatrefages. The hasty appropriation of a citation of one author made by a 

 second, is liable to lead a third author into error. The curious information as 

 to a lacunar circulation in Syllidia, which is imparted to students in the passage 

 extracted from the ' Forms of Animal Life,' is a direct contradiction of 

 the statement of M. de Quatrefages himself, whose accuracy with regard 

 to the corpuscles appears nevertheless to be admitted, since his statement 

 on that matter is made use of by the writer. It does not appear possible 

 that the writer of the ' Forms of Animal Life,' can have read the original 

 statement of M. de Quatrefages quoted below. He appears to have been 

 content to avail himself of a passing reference made by a third person, viz. 

 M. Claparede. M. de Quatrefages writes ('Ilistoire des Anneles,' tome ii, 

 1865, p. 15) in reference to Syllidia armata : — " J'ai vu nettement deux gros 

 vaisseaux contractiles, a parois assez irregulieres, places sur la ligne mediane, 

 I'un au-dessus, I'autre au-dessous du tube digestif, lis sont rnis en communi- 

 cation par des branches laterales a la hauteur de cliaque pied ; mais je n'ai 

 ])u distmguer de ramifications proprement dites. Si elles avaient existe, 

 elle ne m'auraient probablement pas ecb.appe, car, comme je I'ai deja dit, 

 par une exception fort rare chez les Auuelides, le san^ renferme ici des 

 globules bien caracterises." 



