NOTES AND MEMORANDA. 157 



Dr, G. Asper, of Zurich.* In the horse-leech (Aulastovia gulo), as in 

 other Gnatliohdellidce, the male organs usually consist of nine to twelve 

 testes on each side of the body, opening into a common vas deferens, 

 which is convoluted anteriorly, forming the vesicula seminalis. From 

 each vesicula seminalis the seminal duct is continued into the base of 

 the single, median penis. The ovaries are two in number, one on each 

 side ; each is connected with a short oviduct, which joins with its 

 fellow to form a common canal continuous with the muscular vagina. 



The peculiarity of the abnormal form consisted in the fact that 

 the duct from each vesicula seminalis led to a separate penis, so that 

 there were two perfectly distinct intromittent organs, one opening 

 on the twentieth, the other on the twenty-fifth segment. A similar 

 bilateral arrangement existed in the female organs. An ovary was 

 found in the twenty-fifth segment, near the corresponding penis, its 

 duct having a common opening with the latter. A similar female 

 apparatus, consisting of ovary and oviduct, occurred in the thii'tieth 

 segment of the opposite side. 



The Early Development of Equisetaceae. — Taking Hofmeister's 

 account of the development of the JEquisetacece, it was very difficult to 

 make out the exact relation between the first stages of the embryo in 

 this group, and the corresponding stages in the other vascular Crj-pto- 

 gams. In Mr. Vines's paper " On the Homologies of the Suspensor," t 

 the horse-tails are purposely left out of consideration in the com- 

 parison drawn between the embryos of Phanerogams and of the hif^her 

 Cryptogams. But the difficulty seems to be quite cleared up by 

 Sadebeck's recent paper,| in which the early stages in an Equisetum 

 arvense and E. palustre are carefully described, and are seen to corre- 

 spond very exactly with those of, for instance, the fern Ceratopteris. 



The first septum makes an angle of about 70° with the axis of the 

 archegonium, and divides the oosphore into two cells, an upper, the 

 embryo proper, turned towards the neck of the archegonium, and a 

 lower, the embryophore, the homologue of the suspensor of Phanero- 

 gams and of Selaginella. Each of these cells is then divided by a 

 septum at right angles to the first, so that four quadrants are produced 

 the two upper belonging to the embryo, the two lower to the embrj^o- 

 phore. Of the former, one becomes the apical cell of the plant, soon 

 assuming the characteristic form of a short three-sided pyramid with 

 convex base ; the other becomes the first leaf. The latter, alon^ with 

 the two first segments cut oft' from the apical cell, forms the first leaf- 

 sheath of the young plant. Of the two lower quadrants, one becomes 

 the " foot," a temporary organ for the absorption of nutriment from 

 the prothallus, the other becomes the first root, an apical cell being 

 formed, from which the base is soon cut oft' by a tangential septum 

 producing the root-cap. 



Anew Rotifer— Anuraea Ion gispina.— Professor D. S. Kellicott, of 

 Bufialo, U.S., has found § a rotifer in Niagara water at that place 

 * ' Zool. Anzeiger,' vol. i. (1878) p. 297. 

 t ' Quart. Jouru. of Micr. Sci.,' N. S., vol. xviii. (1878). 

 X ' Jahrbliclier f. wiss. Botauik,' vol. xi. (1878). 

 § ' American Journal of Microscopy,' vol. iv. (1879) p. 20. 



