60 BRITISH PALAXOZOIC FOSSILS. [ EcurnopERMATA. 
as if it were marked with three or four longitudinal furrows, crossed at regular intervals by transverse grooves. 
Under surface with short ambulacral plates and broad avenues. 
“This combination of characters gives a singular Ophiura-like aspect to this curious little star-fish ; 
possibly it may not belong to the same genus with the following. It is a gregarious species. Disk to ray 
as 1—4. Breadth of disk 04 inch. Length of ray 03. Greatest breadth of ray 055. 
URASTER PRIMAVUS (Forb.) 
Ref. and Syn.—Asterias primeva. Sedgwick, Letters on the Lake Country, 2nd Kd. Appendix. 
Mem. Geol. Surv. Dec. 1. t. 1. f. 2. 
“Sp. Ch.—Disk broad; arms triangular, short, acuminate. Upper surface irregularly reticulated, having 
probably been studded with tufts of obtuse spines, which were largest on the centre of the arms, so as to 
form a sort of keel. Under surface shewing the double series of linear-oblong, curved ambulacral ossicula, 
which are shorter in proportion than those of the U. Ruthveni. Breadth of disk to length of rays, as 
1—14. Breadth of disk 3 inch. Breadth of ray at base = inch. Length of ray 3 inch. 
Genus. PROTASTER (Forb.) 
“Gen. Char.—Body circular, covered with squamiform plates; genital openings in the angles of junction 
of the arms beneath; arms (simple) formed of alternating ossicula. 
PRoTASTER SEDGWICcKIL (/orb.*) 
Ref.—Mem. Geol. Surv. Dee. 1. t. 4 
“The remarkable fossil, of which, through the co-operation of Professor Sedgwick, we are enabled to 
give a figure, is unique of its kind, and has a peculiar interest in being the only representative of the 
tribe Huryales as yet discovered in the fossil state. I refer it to that tribe, and not to the Ophiure, 
with which at first sight it might be confounded, on account of the alternation of the ossicula of the arms, 
a conformation of which the Asfrophyton and other genera of the former group exhibit examples, whilst 
it is never seen in any genus, as yet discovered, of the latter division. Like many other Silurian fossils, 
this one affords but imperfect materials for an investigation, zoologically, of its characters; such, however, 
as are to be seen in the specimens hitherto procured, are sufficient to enable us to assert with certainty, 
that it is distinct both generically and specifically from any known starfish, whether recent or fossil. 
“The specimen figured consists of tolerably preserved impressions of the upper and under side of the 
disk or body, and of portions of the arms. The disk is circular, and shaped liked that of an Ophiura. 
The arms are five in number, very narrow, equidistant, and similar. 
“The upper and under surfaces of the disk were covered by small, similar, more or less regular, 
polygonal or crescentic plates, imbricated in scale-fashion, and having punctated surfaces. Those of the 
under side of the body are smaller and more regular than those of the upper. The mouth is central, 
* A specimen, ticketed, ‘Ophiura Salteri, Forbes, from the upper Ludlow rock of Shepherd’s Quarry, has been sent to the 
Cambridge Museum by Mr. Salter; on examination I find it to be a specimen of Protaster Sedgwicki, with the scaly circular 
disk very indistinctly visible, except in particular lights. On communicating this observation to my friend, Prof. Forbes, he 
wished his name Ophiura Salteri (which has appeared in some of Prof. Sedgwick’s lists of fossils, and been copied into 
Prof. Bronn’s Index Palxontologicus) to be cancelled. I might add from this specimen that the spinose appendages are 
at least twice the length of the ossicles, and that the ossicles seem to increase in length at a distance from the disk; with a 
high magnifying power some of these spine-like processes seem jointed; if this observation be confirmed by examination of 
more distinct specimens, it will be extremely interesting, as strongly supporting the above view of the general affinities of 
the fossil being with the Crinoids or Ewryales rather than with the Ophiure, in which the apparently similar processes are 
rigid spines for locomotion. —F. M°C. 
