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Show 1900.] OF THE GENUS BENHAMIA. 169 not entirely agree with my observations. The very greatest care has often to be exercised in defining species from these very generally present organs of adhesion, which are often when discreetly used of great value in distinguishing [the species of many genera. These papilla?, however, are of more than one kind. In the present species they are, as Dr. Benham has indicated and illustrated, of the nature of pits from the bottom of which a papilla may protrude. They resemble so far the genital papilla? of the Perichcela, P. novce britannice1. But they are extraordinarily numerous-much more numerous in tbe specimen of Benhamia which I have studied than in that which forms the subject of Dr. Benham's paper. The accompanying drawing (fig. 1, p. 168) will illustrate their distribution on the surface of the body and save a full description. It will be seen from that drawing that they are as numerous in the region of the spermathecal apertures as in the neighbourhood of the male orifices. In Dr. Benham's specimen there were by no means so many of these sucker-like organs anteriorly as posteriorly. The orifices were quite small, and the fact that each was surrounded by a white circumference gave to them an exceedingly conspicuous appearance. In many cases they were crowded together upon a single segment. Elsewhere there were fewer on a single segment. I noticed no glands in the interior of the body which correspond to them. In this they differ from the (physiologically ?) similar papillae of some other earthworms. I divide what I have to say upon the internal organs of this species into three heads :- (1) Calciferous Glands.-These glands, always found in the genus Benhamia, are present to the number of three pairs and, as is usual with the genus, lie in segments xv, xvi, & xvn. The glands are much tabulated, as is shown in the figure which I exhibit (fig. 2, p. 170) ; the furrows are very deep, and the appearance, as Dr. Benham has remarked, is by no means unlike that of a well-convoluted mammalian brain. The middle pair, i. e. those occupying segment xvi, are the largest of the three ; the anterior pair are the smallest. An important anatomical fact respecting these calciferous glands is their opening into the oesophagus by a single orifice on each side, which is common to all three glands. The large size of the worm permitted this fact to be ascertained by simple dissection without any doubt; when the oesophagus was slit open the orifice was not only plainly visible, but the secretion of the glands in the form of a brownish powder was seen to escape like a cloud into the alimentary tube by one orifice only. The slightest pressure produced this result. The single orifice belonged to the anterior gland ; the two following glands apparently communicated with that and with each other. Dr. Benham states of the calciferous glands that "each is . . . connected to the oesophagus by a short, narrow, but distinct duct." i " O n a Collection of Earthworms, &c," Willey's Zool. Eesults, Cambridge, 1899. |