KONTNCK NEW PALAEOZOIC CRINOIDS. 
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preceding, rather thick, and separated from each other by a strong groove. 
The second radial plates are also pentagonal, and broader than long. The axillary 
plate is very thick, and furnished with a slight protuberance, and juts outwards. 
The brachial plates, which follow the axillary plate, offer nothing remarkable. The 
external surface of these plates is indented with little irregular tracings, which 
make it rough, and the test thus resembles shagreen. The arms — twenty in num- 
ber — are composed of cuneiform alternating articulations, and are joined together 
laterally. I have not observed any traces of pinnules. The little plates of which 
the dome is composed are all ornamented with a prominent tubercle in the middle. 
Their surface is apparently smooth, their number variable, and their form is 
generally hexagonal. I have not been able to discover any traces of a horn or 
proboscis, nor of any anal or buccal opening. It is probable these were situated 
between the arms, which were placed on the anal or irregular side of the bulb, 
and that these arms were capable of extension, and of admitting a passage for the 
food of the animal. The stem is rather stout, in comparison to that of most of 
the other species, among which it is often very slight. 
Dimensions — The total length of the bulb is about 40 millemetres ; diameter, 
25 mm. ; length of calix, 12 mm. ; diameter of stem, 4 mm. 
Affinities and Differences. — This species, by the form of its calix, 
approaches to H. graaulatus, Phil, and H. Phillipsianus, De Kon. It is 
distinguished from them by the thickness and convexity of its different 
plates, as also by the rugosity of its surface, which is granulose in the 
first, and perfectly smooth in the second. 
This species was discovered by my excellent friend, Mr. Edw. Wood, 
in the ferruginous beds of the carboniferous limestone in the neighbour- 
hood of Richmond, in Yorkshire. In dedicating it to him, I only feebly 
acquit myself of the debt of obligation which I owe to him for the mag- 
nificent specimens obtained through his indefatigable researches, and 
with which he has so kindly enriched my collection. 
Explanation of figures — PI. IV. : — 
Fig. 5. — Complete specimen, view of the anal side, slightly restored, and of the 
natural size. From the collection of Mr. Ed. Wood, of Richmond, Yorkshire. 
Fig. 5a. — Dome, slightly enlarged, from a specimen in my collection. 
2. Hydreionoerinus Scoticus. De Koninclc. PI. IV., fig. 6, 7. 
As yet I know of this species only the calix. This is rather small, very 
short, and saucer-shaped. Its basal plates are very small, plain, and quadrilateral 
in form. By their grouping they produce a regular pentagon, in the centre of 
■which may be observed the articular face of a small cylindrical stem. The sub- 
radial plates are rather large in comparison with the basal, which are a little less 
long than broad, very convex at the centre, thus forming a protuberance sufficient 
to produce a very decided depression at the base, which remains perfectly 
concealed when the calix is placed on a flat surface. The first radial plates are of 
pentagonal form, and nearly twice as broad as long. They are slightly less arched 
than the preceding plates, but in all the species of the same genus they are situated in 
