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."[1]
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 plates[2] 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[3] 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 predecessors. 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,"[4] and thus describes them:—"Machoires, 3, égales, très petits, demiovales, très comprimées, sans denticules, tranchantes." 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 semioval. 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 Vertèbres,' 2nd ed., vol. v., p. 522.
- ↑ 'Planches; Vers et Zoophytes,' fig. 6.
- ↑ 'Monographie de la famille des Hirudinées;' nouvelle edition, revue et augmentée, accompagnée d'un Atlas de 14 planches gravées et coloriées. Paris, 1846.
- ↑ So also Diessing (l.c.), "maxillius interns tribus." Dutrochet, referring to their presence in other leeches, calls them "tongues" (langues).
