136 CLASS IV, 
- 
remarkable. Amongst the Ophiure, Ophiolepis squamata is vivi- 
parous. The young, about ten in number, are developed between 
the integument and the wall of the stomach of the parent, in the 
inter-radial spaces, each in its own compartment, formed by mem- 
brane extended between the wall of the body and the stomach and 
suspended by a ligament attached near one of the angles of its dise. 
When fully formed it passes out by one of the genital fissures’.] 
In Echinaster sanguinolentus the embryo according to the observa- 
tions of SArs?, on its escape from the egg is of an oval form and 
covered with cilia. Presently excrescences, club-shaped processes, 
arise at one extremity by which it adheres to the inferior surface of 
the disc of its parent, now converted by the infolding of the rays 
into a brooding cavity. When the arms begin to shoot forth these 
processes disappear, and feet or tentacles, few in number but pro- 
portionally very long, serve for the creeping and adhesion of the 
creature. The whole development occupies six or seven weeks. 
When the clavate processes are about to disappear they are near the 
edge of one of the inter-radial spaces of the dise of the Echinoderm. 
Of Comatule it had been discovered by THompson® that during an 
early period of their life they are fixed to a stem and then resemble 
Pentacrini, in other words, that the form which in Pentacrini is 
permanent, is in them transitory. But their previous metamorphoses 
vere unknown. [Buscu has observed these changes from the egg 
until the period when the embryo is about to be attached. The egg 
having passed from the parent by an aperture at the side of the 
pinnule, remains attached to the pinnula by an abundant mucus, 
from spherical becoming oval, and the embryo may be seen rotating 
within the egg by means of its general covering of cilia. When the 
ege falls from the pinnula the embryo escapes: its oval form is 
elongated, the straight sides assume a gently undulating contour: on 
the tops of the undulations transverse bands of larger cilia are seen 
in place of the general ciliated covering: the bands are at first three 
in number, afterwards four, surrounding the body in parallel circles: 
the longitudinal axis of the body now becomes gently curved, and a 
mouth is seen on the concave surface: the bands of cilia disappear 
1 KROUN in MUELLER’S Archiv. 1851, 8. 338—343- 
2 Sars in WreGMANN’S Archiv. X. 8. 169. 
3 THompson, Edinb. New Philos. Jowrnal, XX. p. 295. 
