194 DEVONIAN FAUNA. 



Crinoids, but it seems to have a more conical dorsal cup, a more expanded and 

 shallower basal circlet, and a coarser and more nodulose ornament. Its anal 

 plates seem narrower, and of a different shape. H. elongatus 1 seems a much 

 smoother and more conical fossil, with larger basals. 



3. Hbxacrinus peraematds, Whidborne. PL XXII, figs. 9, 10. 



1889. Hexacrinus perarhattjs, Whidborne. Geol. Mag., dec. 3, vol. vi, p. 79. 



Description. — Dorsal cup small, rather elongate, with slightly convex base, 

 and nearly erect sides. Basal circlet small, nearly flat, hexagonal, formed of 

 three plates. Radials five, rather unequal in width, elongate, very large, 

 subquadrate, sometimes (but not always) expanding upwards, with a large notch 

 or excavation occupying the whole of the upper margin. Anal large, oblong, 

 rather broad (breadth =§ height), surmounted by a subcircular second anal plate, 

 above which appears to be the anal opening. Primibrachs small, axillary, filling 

 only a small part of the radial notch. First secundibrachs large, stout, lunate. 

 Tegmen flat and rather contracted, with a large plate in front of the anus, 

 which is surrounded by about seven other largish plates, most of the other plates 

 of the dome being small, very nodulose, and indistinct. Suture-lines rather deep. 



Ornament consisting of coarse, sharp, elevated pustules, radiating in lines 

 from the tops of the radials, each plate being bounded by a row of rather larger 

 pustules. 



Size of Calyx. — Length 25 mm., width 25 mm., breadth 20 mm. 



Localities. — A finely preserved calyx is in Mr. Vicary's Collection, and another 

 in the Museum of Practical Geology from Wolborough. The cast of a calyx in 

 my Collection from Lummaton seems to belong to the same species. 



Remarks. — The plates of the tegmen are so confused in the only specimen in 

 which they are shown that it seems impossible to decipher them. There seems 

 among others to be one large interainbulacral resting on the upper angle of 

 each pair of radials. In front of the anal opening is a large plate, which seems 

 surrounded by a ring of seven or eight plates, the rest of the plates of the dome 

 being very small. 



Affinities. — It seems rather doubtful whether this is more than a variety of 

 //. macrotatus. It appeal's, however, to differ in the character of its ornament, 

 which does not run into transverse ridges or become confluent, as in that species. 

 The shape of the anal plates is also different; the first plate being larger and 

 squarer, and the anal above it much smaller and shorter than in Austin's species. 



1 1867, Schultze, ' Denksch. kais. Akad. Wissensch. Wien,' vol. xxvi, p. 18G, pi. ix, fig. 1. 



