338 Prof. HK. Claparéde on the Structure of the Annelida. 
mination of the figures of my illustrious predecessor, that these 
facts were perfectly familiar to him*. Thus in every page, in 
the course of this memoir, I shall have to bring Delle Chiaje out 
of the undeserved obscurity in which he has too often remained 
immersed, and to show him shining in the first rank. I ho 
I shall not be accused of partiality in his favour. If I often 
leave his errors, which I admit are numerous, in oblivion, it is 
because they have no influence on the progress of science. 
The circumstances under which I undertook the present 
researches were eminently favourable. Science had just been 
enriched by two important works relating to the Annelida—one 
by M. Ehlers, the other by M. Quatrefages. Both of them pro- 
fessed more or less to represent the actual condition of our know- 
ledge. Aided by this double compendium, I could advance with 
much more certainty upon a road which had been rendered easy. 
I do not conceal from myself how much I am indebted to the 
authors of these works for trouble avoided, for facilitated inves- 
tigation+, for the sapping of errors even before their birth. 
Nevertheless, without injustice towards them, I may be allowed 
to say that the compendium has not always performed what it 
seemed to promise. 
The work of M. Ehlers, of which only one part (including the 
* At the moment I shall only cite an example taken from beyond the 
limits of the subject with which I am at present occupied. A fine Dendro- 
cele Turbellarian, Thysanozoon tuberculatum (Planaria tuberculata, Delle 
Chiaje, Thysanozoon Diesingii, Grube) is found in abundance in the Bay 
of Naples. In studying this animal, I was struck by various anatomical 
peculiarities, but especially by the following one :—The male apparatus is 
formed of two perfectly distinct halves. There exist two penises opening 
outwards, each separately, in the anterior part of the body, in front of the 
female pore. Dendroccela were already known with a single sexual orifice, 
and others with two; but here was one with three apertures. This excep- 
tional fact naturally struck me. But what was my surprise, on turning 
over the works of Delle Chiaje, to find a figure, without explanation, with- 
out text, without even a name at the bottom of the page, representing 
beyond any doubt a portion of the ventral surface of T. tuberculatum, and 
indicating very exactly the three sexual pores (see Deser. e Notomia degli 
Animali senza Vertebre, tab. 109. fig. 19. The male pores bear the letter 
d, and the female pore the letter r). This figure has slumbered since the 
year 1841, unknown to anybody. Delle Chiaje has inscribed at the head 
of one of his works the motto “‘ Res non verba,.” He has been faithful to 
it, perhaps even too faithful. 
* In connexion with this, however, it is impossible for me not to point 
out a defect in the work of M. Quatrefages, which, no doubt, is not to be. 
ascribed to its author. I mean the number of false citations. The quan- 
tity of typographical errors in the indication of volumes, pages, plates, and 
figures exceeds anything that could be imagined, and deprives the work of 
one of the merits which ought to have led to its most frequent consulta- 
tion. . Nowhere would exactitude have been more desirable than in this 
sort of dictionary of science. 
