518 THE ZOOLOGIST. 
terminated at the posterior extremity by a contractile disc. An 
encircling ring, large and slightly elevated, on the anterior third of 
the body. Mouth bilabiate, upper lip larger and obtuse. No teeth 
or jaws. No eyes. Anal aperture on the upper surface of the body, 
near the posterior disc.” * 
In the ‘ Dictionnaire des Sciences Naturelles, vol. xlvii. (1827), 
under the heading “ Sangsue,” De Blainville has given (pp. 205— 
273) a very full account of the Leech family, dealing in detail with 
the anatomy, physiology, and natural history of all the species 
then known. He gives the length of the body in Trochetia (p. 244) 
as two or three inches, and describes the colour as green above, 
yellowish beneath, adding that the number of articulations in the 
body is very considerable. In the accompanying volume of 
platest a figure of this species is given under the name Geobdella 
Trochetii, De Blainville. 
But it is to the elaborate and more recently published work of 
Moquin Tandon { that we must turn for fuller and more accurate 
information concerning this little-known annelid. In several 
important particulars he controverts the statements of his prede- 
cessors. For instance, in regard to the alleged non-existence of 
eyes, he says there are eight—not very apparent at first sight, he 
admits, but nevertheless discoverable on examination. Four are 
disposed anteriorly, in the form of a crescent, on the first segment, 
and four are ranged posteriorly on either side of the third segment 
in lateral and transverse lines. With regard to teeth, which it had 
been stated did not exist, M. Moquin Tandon discovered that there 
are three. To quote his words accurately, however, he designates 
them “jaws,” § and thus describes them :—‘ Machoires, 3, égales, 
trés petits, demiovales, trés comprimées, sans denticules, tran- 
chantes.” These are figured on plate iv. of the atlas of plates, 
figs. 10 and 11; but the representation there given does not quite 
accord with the description in the text, the shape of the teeth as 
figured being sub-triangular and slightly hooked, rather than semi- 
oval. They are smaller and not serrated as in other genera. 
The Rev. W. Houghton, who has paid some attention to the 
* «Hist. Nat. des Anim. sans Vertébres,’ 2nd ed., vol. v., p. 522. 
+ ‘Planches; Vers et Zoophytes,’ fig. 6. 
t ‘Monographie de la famille des Hirndinées;’ nouvelle edition, revue et aug- 
mentée, accompagnée d’un Atlas de 14 planches grayées et coloriees. Paris, 1846. 
§ So also Diessing (l.c.), ‘ mawillius internis tribus.” Dutrochet, referring to their 
presence in other leeches, calls them ‘ tongues” (langues). 
