suspended or floating in an erect position, or slowly swims about in large curves by the continuous and very active motion of its tentacles. This animal may be called the homomorph, amongst the Protozoa, of Sipunculus Bernhardi. I have never been able to satisfy myself as to its mode of feeding, though portions of matter are occasionally seen entangled amongst the tentacles, and apparently pressed in contact with the substance of the proboscis. In the sketch of this animal appended to my notice of 1859, I figured several globular bodies within the sac, which my friend, M. Claparède, to whom I showed it, had not observed; and on further observation, I was led to consider the figure erroneous. In March last, however, the Ophryodendra (Pl. XI. fig. 1) again contained these bodies, and by a somewhat "meddlesome midwifery," I was enabled to force them from the sacs, and to find that they were living young, from four to nine in number. The young thus obtained consist of ovoid bodies of higher refractive structure than the body of the parent, and contain olive-brown corpuscles, shaped like the chlorophyll-granules of Hydra viridis. At a later stage, when the wrinkled trunk of the parent hung lax and dead, the young larvæ assumed a pyriform shape, flattened on their inferior surface. (Pl. XI. fig. 2). This surface was also marked with longitudinal striæ, carrying short, soft, slowly-moving cilia or processes. Their natural mode of extrusion was not observed; but several families of them were found, each enveloped in a soft gelatinous ball, and attached to the Sertularia and other bodies. Single individuals were seen slowly moving on the zoophyte, and others attached were putting forth the rudiments of the proboscis. The proboscis was at first finely molecular, like the contents of the sac, unwrinkled and noncontractile. A few tentacles were presently put forth from its summit (fig. 3), and it gradually assumed the structure of that of the adult. The body of Ophryodendron frequently bears fusiform bodies, from one to four in number, which I have already described, and which appear to be gemmæ. VOL. II. 2 N Explanation of Plates X. and XI., figs. 1-3. Pl. X. Two cells of Sertularia pumila, on which Ophryodendra are attached,— the figure on the left side of the centre with gemma and contracted proboscis, that on the right side of the centre with proboscis extended; the trunks of two others are shown in various stages of extension. Pl. XI. figs. 1-3. Young of Ophryodendron in various stages of development. 3. On Dendrophrya radiata and D. erecta (nov. gen. et sp.). The Rhizopodous animals to which I have given the name of Dendrophrya are found plentifully on Sertularias, Flustras, Fuci, and stones, in low water pools at Granton Quarry, near Edinburgh. There are two species, D. radiata and D. erecta. D. radiata. Its general appearance is that of a small shelly mass, from the borders of which radiates a system of branched membranous tubes, more or less coated with mud or other matters. In young specimens the central shell is absent, and the animal presents the appearance of an irregular system of branches radiating from a centre. The shape of the adults is very various, and depends on the surface to which they are attached; they attain sometimes a diameter of nearly a quarter of an inch, though generally much smaller. The shell is not acted on by acids, and is therefore siliceous. The animal itself can seldom be detected, as it lies concealed within its central flinty stronghold and the complicated system of earthworks surrounding it. D. erecta. In this species, found on stones, the branched, membranous, and mud-clothed tubes, instead of creeping over the surface to which the animal is attached, spring upwards and outwards, as in Pl. XI. fig. 4. Delicate pseudopodia, linear or forked (figs 4. and 5), are readily observed to protrude themselves from the extremities of the branches, accompanied sometimes by lobular processes of the sarcode of the animal. The patelloid shell of D. erecta may be easily detached from its seat, and its tenant, a small patch of semitransparent sarcode, scooped out with a flat-pointed needle and transferred to the stage of the microscope. It PLATE XI. T. Strethill Wright delt et lith. 1.3. Ophryodendron. 4.5 Dendrophrya. |