EOSACEUS, LINCK (COMATULA EOSACEA OE LAMAECK). 
515 
subsequent observations have led me to believe that in some of the later stages the young 
of Antedon were confounded with those of a Turbellarian, which resembled them closely, 
and which during that season accompanied them in great numbers. These earlier obser- 
vations were imperfect and hurried in consequence of the difficulty which I then expe- 
rienced in rearing the young, of their extreme delicacy, and of the rapidity with which 
they passed through their developmental steps. These difficulties have since been to a 
certain extent overcome by the frequent repetition of the observations, and by due regu- 
lation of the temperature of the tanks and of the supply of food and water. 
M. Dujardix has figured* with great accuracy, but without any description, an early 
stage in the development of the pentacrinoid young of Antedon Mediterraneus, Lam., 
which he observed at Toulon in May 1835. The figure represents the oral valves par- 
tially open, with a group of tubular tentacles protruded from the cup. It is highly 
characteristic. 
On the 16th of February, 1863, Professor Allmax communicated to the Royal Society 
of Edinburghf a paper “ On aPrebrachial stage in the development of Comatula.” The 
author procured a single specimen of the stage represented by Dujardix, and in Plate 
XXVI. of the present memoir, among the refuse of a dredging boat on the coast of South 
Devon. Dr. Allmax describes this minute Crinoid as consisting of a body and a stem ; 
the body formed of a calyx covered by a pyramidal roof. The calyx is composed of five 
large separate plates. Between the lower edges of these plates and the summit of the 
stem, there is a. narrow zone, in which “ no distinct indications of a composition out of 
separate plates can be detected.” Between the upper angles of every two contiguous 
plates there may, with some care, be made out a minute intercalated plate. The pyra- 
midal roof which closes the cup is composed of five large triangular plates, each sup- 
ported by its base upon the upper edge of one of the large plates of the calyx, and with 
the small intercalated plates encroaching upon its basal angles. Long flexible append- 
ages or cirri rise out of the calyx, and in the expanded state of the animal, are thrown 
out between the edges of the five diverging plates of the roof. Dr. Allmax counted 
fourteen of these appendages, but could not determine their exact number. “They 
appear to be cylindrical with a canal occupying their axis ; as far as they can be traced 
backwards they are seen to be furnished with two opposite rows of rigid setae or fine 
blunt spines. Between every two opposite setae a transverse line may be seen stretching 
across the cirrus, and indicating its division into transverse segments.” The author 
never succeeded in tracing these appendages to their origin. Besides these long exten- 
sile cirri, there is also an inner circle of short apparently non-extensile appendages. 
It was only occasionally that the author succeeded in getting a glimpse of these. “They 
appear to constitute a circle of slightly curved rods or narrow plates probably five in 
number, which arch over the centre and are provided along their length with two 
opposite rows of little tooth-like spines. They seem to be articulated to the upper or 
* Suites a Buffon. Zoophytes Echinodermes, par M. E. Dujakdin et par M. E. Htjpe. Paris, 1862. 
t Transactions of the Eoyal Society of Edinburgh, vol. zxiii. 
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