192 DEVONIAN FAUNA. 



2. Hexacrinus macrotatus, Austin. PI. XXII, figs. 3 — 8, and PI. XXV, figs. 1, 1 a. 



1841. Platycrinus tubebculatus, Phillips (not Miller, 1821). Pal. Poss., 



p. 134, pi. lx, fig. 39*. 

 1843. Hexacrinus macrotatus, Austin. Mon. Eec. and Poss. Crin., p. 50, pi. vi, 



figs. 3 a — d. 

 1849. Plattcrinus Phillipsii, d'Orbigny. Prodrome, vol. i, p. 103. 

 18S9. Hexacrinus macbotatus, Whidborne. Geol. Mag., dec. 3, vol. vi, p. 79. 



Description. — Dorsal cup large, rather elongate, obtusely pear-shaped or ovate 

 longitudinally, oval in section with diameters of about 4:5. 



Attachment of column very large. Basal circlet large, hexagonal, forming a 

 rather shallow cup composed of three hexagonal basal plates, of which two are 

 sometimes larger than the third, and which are short, being nearly twice as wide 

 as high. Radials five, very large, considerably longer than wide, subquadrate 

 or subpentagonal (according as they rest on the centre of a basal or on the sides 

 of two adjacent basals), increasing in width upwards, deeply excavated on the 

 upper margin. Primibrachs confined to a single row, minute, axillary, not filling 

 the excavation. First secundibrachs large, lunate. Anal plate resting on the 

 basals, similar to the radials (between which it is intercalated) but decreasing in 

 width upwards, followed by a smaller square interradial. 



Tegmen rather small, flattish, constricted, consisting of a few large central 

 polyhedral plates with some very small plates in the distal region. 



Ornamentation coarse and confluent ; three or four rows of sharp but 

 confluent nodules on the basals, the first of which forms an intermittent ring round 

 the attachment of the column. Radials with raised bevelled margins, and three or 

 four irregular transverse nodular bands. Suture-lines deep and widely angular. 

 Size of Calyx. — Height 33 mm., width 30 mm., breadth 32 mm. 

 Locality. — Wolborough. There are two specimens in the Museum of Practical 

 Geology, four specimens in Mr. Vicary's Collection, one in the British Museum, 

 and one in my Collection. 



Remarks. — One of the specimens in the Museum of Practical Geology is clearly 

 the original of Austin's fig. 3 a. The other is exceedingly fragmentary ; but from 

 the shape of the remaining matrix and from the fact that it shows a single secundi- 

 brach it appears in all probability to be the original of Austin's fig. 3b, but injured 

 after drawing, having lost its basal part. As the fossil was evidently fragile, such 

 an accident might easily have occurred. If this be so, it is also in all probability the 

 original of Phillips's Devonian figure of PI. tuberculatus, which, although the matrix 

 is unrepresented, shows the single remaining brachial, and of which he writes, 

 " it has the air of PI. tuberculatus, Miller, but its surface is perhaps only rough by 

 the weathering of the stone; its scapular plates are longer and its pelvis more 



