56 BRITISH PALAXOZOIC FOSSILS. [ Ecu1nopERMATA. 
the outer of which continues simple, but the inner one branches again near its extremity; the outer finger 
of each hand continues simple for rather more than three lines, then branches once; all the fingers are 
densely tentaculated (of two rows of joints). 
Position and Locality—Numerous perfect specimens of this little species, with their rays and columns 
attached, are preserved on a thin slab of Upper Silurian flag from Nant-gwchwyd-uchaf, S. of Llangollen ; 
fragments of the remarkable column with the spine-like auxiliary processes in the Upper Ludlow quartzite 
of Shepherd’s Quarry, Kendal, Westmoreland. 
Explanation of Figures.—P1. 1. D. fig. 3. Part of large slab from near Llangollen, natural size, shewing 
three perfect cups with their rays, attached to their columns, and some portions of the older columns. 
Genus. PERIECHOCRINUS (Aust.) 
Ref. and Syn.—Austin, Ann. Nat. Hist. 1843, p. 203. = Geocrinus (D’Orb. 1847). 
Gen. Char.—Pelvis (of three plates) Ist and 2nd primary radial plates (costa/s) hexagonal; 38rd 
ditto (or scapula) pentagonal, supporting two nearly similar hexagonal, 1st secondary radial (arm) plates, 
each supporting a pentagonal 2nd ditto, from each of which proceed two rows of tertiary radials, that 
on the outer side ending in one very long simple finger, that on the inner side giving off two fingers, 
the outer one simple, the inner one soon dichotomising; all the fingers have two rows of joints, with 
long plumose tentacles; each of the five rows of primary, secondary, and tertiary radials (costals, scapule, 
and arm-plates) more prominent than the other plates of the cup (often keeled); none of the plates 
conspicuously radiated; above and between the two Ist secondary radials (arm-joints), is situated in each 
row one large hexagonal interbrachial plate, surmounted by two smaller, and so blending with the capital 
plates; the interradials are irregular, being apparently one hexagonal Ist interradial between the 2nd 
primary radials, surmounted by two or three 2nd interradials between the scapule, or 3rd primary 
radials, succeeded by more numerous polygonal plates, blending with those of the summit; co/wmn round, 
of alternately thicker and thinner joints. 
The remarkable characters of the secondary and tertiary radials or arm- and hand-plates being flattened 
and forming part of the walls of the cup, leaving only the fingers free, distinguish this complex crinoid 
from <Actinocrinus. The specimens I have examined are unfortunately crushed about the pelvis, so that 
I have doubts as to the propriety of separating Glyptocrinus of Hall from Periechocrinus ; the comparatively 
smooth plates in the latter, however, and the pelvic plates not being divided vertically under the middle 
of the Ist primary radial (or Ist costal), go to prove the correctness of the separation. 
PERIECHOCRINUS MONILIFORMIS (J/ill. Sp.) 
Ref. and Syn.—Actinocrinus moniliformis Mill. Crin. Id. Phill. Sil. Syst. t. 18. f. 4. = P. costatus 
Aust. Ann. Nat. Hist. Vol. XI. p. 204. 
Sp. Ch.—Cup from pelvis to base of fingers conoidal, little wider than long; a strong ridge extends 
from the pelvis up each of the primary radial rows, branching at an angle of 40° on the scapular or 
3rd primary radial plate, the two branches running up the secondary radials or arm-plates, and again 
dichotomising to the tertiary radials or hands; Ist, 2nd, and 3rd primary radials (or costal and scapular 
plates) as long as wide; joints of the column very tumid; fingers strong, nearly four times the length 
of the cup; average length of cup one inch ten lines. 
Position and Locality—Common in the Wenlock limestone, Dudley, Staffordshire. 
Genus. GLYPTOCRINUS (fHall.) 
Gen. Char.—Cup pyriform, pelvis of five, hexagonal or pentagonal pieces, alternating above which are 
five pentagonal 1st primary radials (first costals), each supporting a hexagonal 2nd ditto (second costat), 
on which rests a heptagonal 3rd ditto (scapula), bearing two rows of secondary radials or arms, of two 
