120 BRITISH PALAZOZOIC FOSSILS. (EcuinopeRMATA. 
radial or scapula; visceral plates very large, irregular, polygonal, some of them nearly equalling the 1st primary 
radials (seapulze) in size, they are moderately convex, and each rendered rugged by several small tubercular 
projections; mouth lateral, surrounded by small plates. Length of small specimens from pelvis to vertex six 
lines, width eight lines. 
The very large, bubble-like tuberculation of the visceral plates and the small, gibbous scapule give a most 
peculiar aspect to this species, quite unlike any other I am acquainted with. I find the characters very con- 
stant, 
Position and Locality.—Not uncommon in the carboniferous limestone near Bakewell, Derbyshire. 
Explanation of Figure-—Plate 3. D. fig. 3. Profile of specimen natural size. 
Genus. ACTINOCRINUS. See page 55. 
Actrnocrinus (Amphoracrinus) ATLAS (M*Coy). P1.3. D. fig. 5. 
Ref—Am. Nat. Hist. 2nd Series, Vol. i. p- 248. 
Sp. Ch.—Body elongate-oval, diameter between the arms little more than half the height of the body ; pelvis 
pentagonal, of three thick flattened joints ; Ist interradial small, pentagonal; five Ist primary radials hexagonal, 
nearly twice as wide as long; 2nd primary radials as long as the first, but only one-third wider than long, hexa- 
gonal or sometimes quadrate (according as the upper lateral angles are entire or slightly truncated) ; 5rd primary 
radials (scapul) short, pentagonal, as wide as the 2nd primary radials ; interradials hexagonal, exceeding the Ist 
primary radials in length ; arm-bases prominent, and over each is an elongate conical tubercle ; pectoral plates 
rather large, convex and irregularly polygonal ; vertex covered by a very large hemispherical plate, surrounded by 
six slightly smaller polygonal ones, each having a large conical protuberance in the middle ; mouth longitudinally 
oval, rather nearer the vertex than the arm-base over the pentagonal 1st interradial, to which it inclines; all the 
plates except the large ones of the vertex marked with minute vermicular wrinkles. Length from pelvis to 
plate on vertex one and a half inch, diameter between the arms ten lines. 
The enormous size of the visceral portion above the arms (nearly three times the height of the cup) has 
suggested the specific name for this crinoid, which resembles the A. (Amphoracrinus) Gilbertsoni and A. (Am- 
phoracrinus) amphora in its markings, prominent tubercles over the arm bases, and great plates on the vertex ; 
but it differs from those, besides the great size of the visceral portion, very obviously in the greater proportional 
length and less width of the radials, most remarkably of the second series. 
Position and Locality—Rare in the carboniferous limestone of Bolland. 
Explanation of Figure —Plate 3. D. fig. 5. Profile of specimen, natural size. 
ACTINOCRINUS GILBERTSONI (J7//.) 
Ref. and Syn.—Actinocrinus Gilbertsoni Mill. Phillips, Geol. York. Vol. II. t. 4. f. 19. 
Sp. Ch.—Cup very short, concave, conic ; arms large, the diameter at their base equal to the depth of the 
cup; prominent, abdominal portion of cup above arms very large, tumid, three times as high as the depth of 
the cup; near the vertex is a large convex plate, surrounded, except near the mouth, by a circle of smaller 
large convex plates; mouth small, longitudinally oval, half-way between the central plate and the bases of the 
two arms over the pentagonal Ist interradial; rest of abdominal plates small, convex, except one sharp conical 
one near the base of each arm; plates of the cup formed and sculptured as in the A. amphora, but the primary 
radials much wider and shorter, the length of the Ist and 2nd primary radials together, only two-thirds the 
width of the Ist primary radial, and the sculpturing more minute. 
The height considerably exceeds the width, which with the smaller and more lateral mouth, small spiniform 
arm-tubercles, smaller size, and the above-mentioned characters of the plates of the cup distinguish this from the 
A, amphora. 
Position and Locality.—Carhboniferous limestone, Bolland. 
