ZOOLOGY AND BOTANY, MIOROSOOPY, ETO. 
431 
the anterior ventral surface but no anus, a well-developed coelomic 
pouch on each side of the digestive tract, and a hydrocoel with five pri- 
mary tentacles and five secondary outgrowths opening to the exterior 
through the dorsal pore, by means of an adradial water-canal, upon 
which may still be seen the vestige of an anterior coelom. Then follows 
the development of the pentactula. Its characteristics may be briefly 
summed up as follows : — Water- vascular system consisting of a closed 
hydrocoel or circumoral water-tube with five primary tentacles, between 
which are five very much smaller but equally erect secondary outgrowths ; 
a water-tube in the mid-dorsal interradius connecting the circumoral 
vessel with the exterior ; and a Polian vessel in the left dorsal inter- 
radius. Nervous system consisting of a circumoral ring ; five tentacle 
nerves on the inner face of the primary tentacles, the ectoderm of which 
is considerably thickened, especially on the outer side ; five radial nerves 
bending backward over the secondary outgrowths of the water-ring and 
over the radial pieces of the calcareous rings, and running to the poste- 
rior end of the body ; and five pairs of otocysts lying external to the 
radial nerves, where they bend backward. Digestive system, consisting 
of a short oesophagus with the mouth opening anteriorly in the centre 
of the circle of tentacles, a large stomach, a comparatively short intes- 
tine with a single loop in it, and usually an anus formed secondarily 
near or at the aboral pole. Digestive system attached to the wall 
throughout its whole course by a mesentery, formed by the union of the 
two walls of the right and left coelomic pouches. Calcareous ring, con- 
sisting of five radial and five interradial pieces with much-branched 
ends. A few scattered glandular organs of doubtful function in various 
parts of the ectoderm. The author then traces the development on to 
the adult, and gives a short account of the structure of the adult. As 
regards the phylogenetic position of Synapta, he agrees on the whole 
with Ludwig that the Synaptidae are degenerate pedate Holothurians ; 
as regards general embryological results he agrees closely with Bury. 
Protandric Hermaphroditism of Asterina gibbosa.* — Prof. L. 
Cuenot has made an interesting study of this hermaphrodite species. At 
Roscoff, the individuals are males for one to two years, and then become 
females ; at Banyuls, the individuals are males for an indefinite number 
of years, at least two to three, then become females ; at Naples, there is 
remarkable sexual polymorphism, some are wholly male, others wholly 
female, others hermaphrodite impartially, others transitional. 
Ccelentera. 
Movements of Hydra.')' — Herr W. Zykoff describes the protrusion 
of fine pointed pseudopodia from the ectodermic cells of the tentacles of 
Hydra, fusca, and maintains that these function in attachment and loco- 
motion. He discusses the various views already propounded as to the 
polyp’s movements. 
Grafting Experiments on Hydra.J — Herr G. Wetzel has elaborated 
his previous experiments. He first describes grafting between indi- 
* Zool. Anzeig., xxi. (1898) pp. 273-9 (3 figs.). 
t Biol. Centralbl., xviii. (1898) pp. 270-2 (1 fig.). 
X Arch. Mikr. Anat., lii. (1898) pp. 70-96 (1 pi.). 
