THE BLOOD-CORPUSCLES OF THE ANNELIDES. 487 



are still based, mainly, though not exclusively, upon Leuckart's 

 account of these systems in this animal and some of its allies at 

 pp. 651, 652, 665, 670 of the first volume of 'Die Menschlichen 

 Parasiten,' published in 1863. It would take too much space to 

 reproduce these valuable pages here ; most of them are referred to 

 in 'Forms of Animal Life'' (pp. 138, 140), and Professor Lankester's 

 phrase that the vascular fluid of Branchiobdella ' notoriously differs,' 

 &c, has suggested to me, among other things, that it will be more 

 than sufficient for my purpose to show from references to the utter- 

 ances of the various writers who have referred to the matter subse- 

 quently to the appearance of Leuckart's work, that, as regards 

 \ notoriety,' Branchiobdella is ' notoriously ' taken as the typical 

 'text-book' illustration of the points which I specify. 



Firstly, then, Professor Oscar Schmidt, well known to English 

 readers as the author of ' The Doctrine of Descent and Darwinism/ 

 in the fifth edition of his 'Handbuch der Vergleichenden Anatomie' 

 (1865) 1 , writes as follows with reference to the circulatory system 

 of the Hirudineae : — 



' The Discophora manifest the most remarkable relations, as it is only in Branchi- 

 obdella that the perivisceral cavity presents itself as an actual roomy cavity, with 

 which the single large vessel running above the intestinal canal communicates.' 



This statement is repeated in the sixth edition (p. 108), word for 

 word, except so far as the substitution of the word 'Egel' for 

 ' Discophoren ' makes a difference. 



Professor Claus, in the first edition of his ' Grundziige der 

 Zoologie' (1866), in which (p. viii.) he expressly acknowledges the 

 assistance given to him by Leuckart, has the following passage in 

 a page (p. 155) where Leuckart's researches upon the circulatory 

 system of the Hirudineae are specially referred to : — 



1 It will furnish encouragement, perhaps, to lecturers just entering upon their first 

 course of Comparative Anatomy Lectures to read the following passage prefixed to this 

 edition of Professor Oscar Schmidt's ' Handbuch.' Persons who are as little liable to 

 discouragement may, ceteris paribus, hope ultimately to attain to an eminence as great 

 as that of the now deservedly well-known Professor. His words are : — ' In Sommer 

 Semester 1849 las ich zum ersten Male in Jena uber vergleichenden Anatomie. Von 

 den drei Wissbegierigen welche sich gemeldet war der eine schon mit der ersten 

 Stunde befriedigt, und war nicht mehr gesehen. Die beiden anderen bezeigten mir 

 ihre Sympathie bis zum Schluss ; nie schwanzten sie zugleich. Das war fiir dieses 

 Buch sehr wichtig, denn aus den fleissigen Vorbereitungen zu jenem Collegium und 

 unmittelbar aus diesen ersten, oft in ein Zwiegesprach iibergehenden Vortragen 

 entstand es.' 



