184 
CRINOIDS. 
Aug., 1891 
Within the last fifty years naturalists have devoted great 
attention both to fossil and recent crinoids, and though it 
must be a matter of regret that British palaeontologists have not 
kept pace with their foreign confreres in this branch of geology, 
we may congratulate ourselves on the publication of the mag¬ 
nificent monograph, by Dr. P. H. Carpenter, on the crinoids 
dredged by the “ Challenger ” expedition during the years 
1878-1876, which is a work unsurpassed both for its scientific 
importance and completeness, and the beauty of the 
illustrations. 
Having thus imperfectly epitomised the history of the 
crinoids, for which I am chiefly indebted to De Koninck andLe 
Hou’s “ Keclierches sur les Crinoides du Terrain Carbonfere de 
la Belgique ” (1858), I will now speak briefly about the animals 
themselves. 
As you are all aware, they are placed in the division, 
Echinodermata, in which they form a separate class, Crinoidea. 
The body of the animal is supported, generally, on a stem, 
which is most frequently fixed either in the ooze of the sea 
bottom, or to seaweeds, zoophytes, &c., by root-like cirri, or 
by an expansion of the base of the stem. The stem consists 
of a number of circular or pentagonal ossicles, which are articu¬ 
lated together, and have a circular, five-sided, or five-lobed 
orifice in the centre for the purpose of holding nervous and 
muscular fibres. In many species a number of prehensile cirri 
rise at intervals from the stem, thus serving to help the animal 
to anchor itself when in any current. At the top of the stem 
is a cup formed of numerous or few plates, which give off 
arms. These arms are sometimes simple ; sometimes they 
divide into two parts, dividing again and again into a large 
number of fingers. These fingers and arms give off lateral 
pinnules, being all composed of calcareous plates, neatly 
articulated together. The soft parts of the animal are formed 
of a gelatinous integument which covers the whole skeleton, 
and which comprises the visceral and other organs, placed in 
the cup of the skeleton, and extending over the arms and 
pinnules. They possess a digestive canal with mouth and 
vent. The visceral organs are often protected by a disc of 
thin plates. The food is conveyed to the mouth by means of 
ciliated grooves in the interior of the arms. The marvellous 
complexity of the plates of the calyx and arms may be shown 
by the fact that in Encrinus liliiformis they number upwards 
of 13,000, according to a calculation made by Mr. F. A. 
Bather, of the British Museum, who is now writing a series 
of papers on British Fossil Crinoids in the “Annals and 
Magazine of Natural History,” and who estimates the number 
