ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 59 
Variations in Larva of Asterina gibbosa.* * * § — Mr. E. W. MacBride 
describes certain variations which seem to prove that the sac which he 
has called the right hydrocoele is a structure of the same nature as the 
left. As the larva in its early stage is quite bilaterally symmetrical, it 
may be assumed that the free-swimming pelagic ancestor of the Echino- 
derms had two equally developed hydrocoeles ; the variations described 
may, for the most part, be put under the head of atavism. 
Coelentera. 
Indian Actiniaria.j — Dr. A. Alcock reports from the Indian Seas 
five species of Zoanthkke and a new variety of Sphenopus arenaceus. The 
only Cerianthid found is Ceriantlius andamanensis , which appears to be 
very close to C. americanus. 
Spongodes.J — Herr 0. Holm makes a contribution to our knowledge 
of this genus of Alcyonids. After a general historical review, he divides 
it into four subgenera thus — 
I. Polyps not united in distinct bundles. 
a. Branches lobed. 
a. Spicules of the tentacles arranged in two regular longi- 
tudinal rows 1. Nephthya 
/3. Spicules of tentacles scattered irregularly 2. Panopes n. 
b. Branched elongated, cylindrical. ... 3. Spongodia 
II. Polyps united in distinct bundles .... 4. Spongodes 
A considerable number of new species are described. 
Flabellum anthophyllum.§ — Prof. H. de Lacaze-Duthiers has pub- 
lished a full report of his observations on this Coral, the preliminary 
notice of which we have already |] noted. The history and structure of 
Flabellum are now detailed, with references to figures of great interest. 
Stinging Organs of Hydroids.lf — Herr L. Murbach distinguishes in 
the stinging-cell, (1) a structure which facilitates the action of the 
poisonous secretion ; (2) a muscle which sets the weapon in action ; (3) a 
sensory hair associated with the muscle, and perhaps also with nerve- 
elements more deeply situated. 
The capsule consists of a very delicate vesicle surrounded by a firm 
outer wall. The vesicle owes its origin to the nucleus ; the outer wall is 
formed from the material secreted around the vesicle during its formation. 
The tubular thread is formed, as a continuation of the vesicle, from the 
protoplasm surrounding the nucleus, and its mode of origin explains its 
spiral coiling. By the removal of water from the mass surrounding the 
vesicle an osmotic pressure is exerted on the vesicle, and this is the cause 
of the extrusion of the thread. Vesicle and thread are, beyond doubt, 
intracellular products. 
* Proc. Camb. Phil. Soc.. viii. (1894) pp. 214-7. 
f Journ. Asiat. Soc. Bengal, Ixii. (1893) pp. 151-3.' 
i Zool. JB. (Abth. f. System., &c.), viii. (1894) pp. 8-57 (2 pis.). 
§ Arch. Zool. Exper., ii. (1894) pp. 445-84 (1 pi.). 
|| See this Journal, 1894, p. 457. 
If Arch. f. Naturges., lx. (1894) pp. 217-54 (1 pi.). 
