Miscellaneous, 309 Capri, M. Hackel was also occupied with these animals on the shores of Dalmatia, and had likewise ascertained the existence of zoosperms and ova in the calcareous and siliceous sponges *. The results of his researches had even been published a little before the memoir of M. Eimer. The latter, however, thinks Hackel, like Huxley and Lie-berkiihn, had not under examination any completely developed zoo-sperms, but only slightly advanced forms of those elements. As, however, Hackel has observed a direct fecundation, M. Eimer hazards the supposition that there may be some sponges in which the zoo-sperms are arrested at one of the inferior stages of their develop-ment. — Archiv fur mihroskojjische Anatoynie, vol. viii. Heft 2; Bihl. Univ. August 15, 1872, Bull. Sclent, p, 350. Investigations upon the Development of the Gregarinae. By E. VAN Beneden. The investigations of M, E. van Beneden upon the Gregarina gignntea of the lobster confirm the observations of Lieberkiihn upon the transformation of certain amoeboid forms into Gregarince ; only the phases are here somewhat different from those observed in the Gregarince of the earthworm. The author found, in the small intestine of the lobster, some small, finely granular, protoplasmic masses, destitute both of membrane and nucleus. These masses, which are continually changing their form, greatly resemble Prota-mceba primitiva or P. agilis of Hackel, from which they differ only by presenting fine molecular granulations even to the peripherj', and by never emitting true pseudopodia. According to HackeFs nomen-clature, these would be true gymnocytodes. Side by side with these we find small protoplasmic globules, which differ from them only by having lost the faculty of moving and changing their form. They have no enveloping membrane any more than the former ; but their spheroidal form is preserved by a peri-pheral layer of denser and less fluid protoplasm. With these globular and motionless forms we find others perfectly similar to them, except that they have one or two prolongations which cannot be assimilated to pseudopodia, but rather to the movable stalk of the Noctiluece. M. van Beneden names these generative eg fades, because it is these which directly give birth to the Gregarina'.. When there are two prolongations, these are inserted at but a little distance apart. One of these prolongations, which is shorter and more slender and with paler outlines than the other, and only contains very fine granules, is almost destitute of mobilitj^ When brought against a hard body, it is seen to bend ; and the bend thus produced persists for a very long time. The other prolongation is considerably longer and stouter, with stronger outlines and a more refractive protoplasm. Besides a very fine punctation, it contains opaque granules, which are very numerous at its slightly widened extremity. This process is endowed with an extreme mobility, which is manifested in two modes. It may swing about like the stalk of the Noctiluece, or present an inflection * Jenaische Zeitschrift, vol. vi. Heft 4.