ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
53 
Mr. MacBride denies its existence ; he points out that what looks like a 
blood-vessel is limited by no cell-layer from tho nerve-fibres below, and 
its boundary towards them is often jagged and uneven, while the angles 
of the outline run out into vertical fibres, and convey the impression 
that the so-called blood-vessel is merely composed of the cell-plasma of 
two or three rather larger dorsal ganglion-cells which are prolonged into 
these fibres. As to the so-called branches of the haemal system which 
go to the alimentary canal, they appear to be nothing more than 
mesenteric bridles. 
Morphology of Skeleton of Starfishes.* — Prof. E. Perrier finds that 
the arm of Hymenodiscus has its skeletal parts so reduced as to make it 
impossible as a point of departure. He starts, therefore, with the arms 
of Brisinga and Odinia ; in Labidiaster there is further complication ; 
the author recognizes adambulacral plates connected with one another 
by five longitudinal rows of small plates ; the third and fifth plate of 
each have a spiral form, and may be called the ventral marginal and 
dorso-marginal, while the seventh plate, which occupies the medio- 
dorsal line of the arms may be called the carinal. Here we have the 
fundamental parts of the arms of Starfishes. The term ventro-lateral is 
applied to the piece between the adambulacral and the ventral marginal ; 
intercalary to those which unite the ventral and dorsal marginals; 
dorsolateral to those which unite the latter with the carinals ; and reticu- 
lar to the pieces set in longitudinal or oblique rows which pass from 
one arch to another. 
All the modifications of form seen in Starfishes depend solely on the 
relative development and numerical relations of their different systems 
of plates. When the ventral and dorsal arches are formed in the same 
way from the base to the tip of the arms, these, which are cylindrical or 
conical, are sharply distinguished from the disk, which is circular. 
When the ventral and dorsal arches are more developed at the base than 
at the tip, there is a tendency for the disk to take on a pentagonal form. 
Prof. Perrier thinks it is permissible to regard the arms of Starfishes 
as primitively formed of successive segments, and that the relationship 
so often noticed between Echinoderms and Vertebrates receives support 
from this view. 
Holothurians collected by the ‘ Hirondelle.’f — Dr. E. von Maren- 
zeller has a preliminary notice on the Holothurians collected by the 
Prince of Monaco during the voyages of the ‘ Hirondelle.’ The new 
species are Holothuria lentiginosa , Benthodytes janthina, Peniagone azorica , 
and Chiridota abyssicola. The ranges of some new species are increased, 
the southern Cucumaria dbyssorum having been found in the Atlantic, 
and the littoral Synapta digitata taken at a depth of 2870 metres. 
Coelentera. 
Larva of Euphyllia.J — Prof. A. C. Haddon gives an account of a 
newly hatched larva of Euphyllia rugosa which he observed in the Torres 
Straits. The only differences in the mesenteries between this larva and 
* Comptes Rendus, cxv. (1892) pp. 670-3. 
f Bull. Soc. Zool. France, xvii. (1892) pp. 64-6. 
% Scientific Proc. R. Dublin Soc., vii. (1892) pp. 127-36 (1 pi.). 
