Page:The Zoologist, 3rd series, vol 1 (1877).djvu/545

Rh Leech family, failed to detect these teeth; but, as Mr. Jabez Hogg has observed, they are so exceedingly small, when compared with the size of the animal, that they can only be got out with some difficulty, and by a careful, dissection. The parts then require to be soaked and prepared in the usual way for mounting in balsam, to render them sufficienliy transparent for a power of 150 diameters and upwards. Referring to Moquin Tandon's figure, Mr. Hogg characterizes it as "very inferior; the mouth, jaws, and teeth very much more resembling those of the Echini than of the ordinary leech." "The teeth," he adds, "are placed in a triangular form and are hooked and very acute, for grasping and bruising."

Moquin Tandon's observations of Trochetia lead him to believe that it is only serai-terrestrial in its habits, for he succeeded in keeping specimens in water for a fortnight in good health. It is to be found, he says, in little rivulets and gutters in the fields, whence it comes forth occasionally to prey on earthworms, in pursuit of which it is almost as voracious as Aulastoma.

In regard to its reproduction it is not hermaphrodite, as some leeches are said to be, but individuals of both sexes are found. The female is oviparous, and forms, in a moist tunnel in the ground, a small capsule or cocoon containing numerous ovules, from which the embryo leeches are usually hatched at the end of forty days. The young leech is white when first hatched, and does not begin to acquire colour until some hours afterwards. The perfect colouring is not attained for two years. Its first food consists of the mucous matters which cover the leaves of aquatic plants; afterwards, when its mouth has become more developed, it feeds on the larvæ of insects and other small animals.

The colour of Trochetia seems to vary in individuals, the normal coloration being a dull greyish green, with two longitudinal dorsal stripes of a brownish shade. Moquin Tandon describes five other varieties under the names rufescens, nigricans, brunnea, rubella, and carnea, which sufficiently indicate their prevailing tints.