206 DEVONIAN FAUNA. 



of the arms almost half-way to the centre of the disc. Arms rather longer than 

 the width of the disc, slight, composed of rows of few long and level ossicula, 

 bearing on each side at long regular intervals a single large, long, thorn-like spine 

 (which in the fossil is occasionally bent, possibly from accidental causes). 



Size. — Total width of specimen 8 mm. (If perfect and untwisted it probably 

 would measure 9 or 10 mm.) Disc 2*5 mm. Arms between 3 and 4 mm. long. 



Locality. — A single specimen from north-east of Harford Landkey is in 

 Mr. Handing's Collection. 



Remarks. — It was only after the description of the last species was in print 

 that I found this interesting little fossil in a slab sent to me by my friend 

 Mr. Hamliug. Though minute, and in such defective preservation that it is 

 impossible to make out the arrangements of its plates, it is sufficiently clear to 

 leave no doubt whatever as to its general character. Its sixteen arms can be 

 definitely counted, and the few long distant spines that margin them are evident, 

 though sometimes they seem curiously bent. The plates of the arms have the 

 appearance of being remarkably long. 



Affinities. — This species appears to be congeneric with M. Rhenanus, Sturtz, 1 but 

 is distinguished from it by its small size, its much larger disc, its more numerous 

 arms, and several other particulars. 



Helianthaster Rhenanus, Ferd. Romer, 2 is very much larger, its disc is relatively 

 smaller, the plates of its sixteen arms more numerous and differently arranged, 

 and the spines much more numerous. 



3. Class— OPHIUROIDEA, Wright, 1857. 



1. Order— OPHIUREA, Zittel, 1879. 



I. Family — Ophio-encrinasteri,e, Sturtz, 1886. 



1. Genus— Protaster, Forbes, 1849. 



Stiirtz 3 and Dr. Gregory 4 have both pointed out that various species, differing 

 in important particulars from each other, have been referred to this genus, and that 

 it greatly needs revision. "While, therefore, until this be done, it may be necessary 

 still to refer species of unlike aspect to it, it is best to remember that neither 

 F. Miltonii, Salter, nor P. Forbesii, Hall, nor P. brisingoides, Gregory, 4 but 



1 1890, Sturtz, ' Palseontographica,' vol. xxxvi, p. 229, pi. xxxi, figs. 34, 35. 



2 1863, Ferd. Romer, ' Palaeontographiea,' vol. ix, p. 147, pi. xxviii, fig. 1. 

 s 1886, Sturtz, ' Palseontographica,' vol. xxxii, p. 79. 



4 1889, Gregory, ' Geol. Mag.,' Decade 3, vol. vi, p. 24, woodcuts 1 — 4. 



