Aug., 1891. history of the county botany of Worcester. 185 
of plates in the Thenarocrinus callipygus , a new species from 
the Dudlev limestone, as 48,290. 
Orinoids are gregarious in their habits, and frequently 
form vast colonies. Dr. Carpenter states that 10,000 have 
been brought up by a single haul of the dredge, and the 
swarms of Extracrinus that are found in the Lias beds of 
Lyme Eegis, together with the innumerable stems found in the 
Derbyshire limestone, of which they form almost entire beds, 
testify that this habit was common to them in ancient 
geological periods. 
They can live apparently only in clear water, and an influx 
of muddy water seems to be fatal to them. As an instance 
of this fact, I may say that a few years ago, in working the 
upper bed of limestone at Dudley Port, an immense number of 
crinoids were found, more than have been met with anywhere 
else in the district, lying on a thin seam of fine shale, inter¬ 
calated with the crystalline limestone. 
The food of the crinoids consists of foraminifera, diatoms 
and small Crustacea, with the lame of larger ones, and I may 
mention, in this connection, that a serious mistake was made 
by former palaeontologists in mistaking the anal tube for a 
proboscis or mouth ; and Mr. J. W. Salter, in Murchison’s 
“ Siluria,” gives an exaggerated figure of a Marsupiocrinus 
with the proboscis, as he calls it, inserted in the chamber of 
a gastropod, and, as he says, feeding on it. It is now known 
that the gastropod is feeding on the excreta of the crinoid, 
instances of which have also been met with on American 
fossil crinoids. 
The geological range of the crinoids is very extensive, for 
specimens of stem joints are recorded from the Cambrian 
rocks, and they are distributed in subsequent formations in 
most countries. Though the recent crinoids affect mostly 
warm latitudes, and a sea depth less than 500 fathoms, they 
are capable of supporting existence apart from these two 
conditions, for Dr. Carpenter states that specimens of 
Autedon were dredged by the “Challenger” at a depth of 
nearly 3J miles in the Pacific Ocean, and at almost three 
miles in the South Sea ; and that Comcitulce were found at 
from 81° N. to 52° S. latitude. 
In conclusion, let me add that the fossil crinoids are 
among the fairest ornaments of the geologist’s cabinet, and 
that Dudley is pre-eminent for the variety of species found 
in the Wenlock Limestone of that neighbourhood, and also 
for the wonderful state of their preservation, enabling the 
student to work out very successfully the minutest details of 
their marvellous structure. 
