OCCUERENCEOF STARFISH IN UPPER SILURIAN SERIES — ETHERIDGE. 129 



With Palasterina* there is a resemblance in the quadrangular 

 adambulacral ossicles bordering the ambulacra, but the difficulty 

 is increased by the absence of certainty as to the presence or not 

 of a second row of plates, Plasterina having but one row, whilst 

 PalcBocoma possesses two. At the same time there are unquestion- 

 ably combs of spines along the edges of the ambulacra, which would 

 favour the presence of a second row of plates as in the latter genus. 

 Furthermore, the appearance of the disk is much more akin to 

 that of Falnocoma than Palasterina, and on the whole it appears 

 to me preferable to refer the Bowning fossil to the former genus 

 rather than to the latter. 



A difficulty now presents itself with regard to the name Falceo- 

 coma. Salter proposed it in 1857,t although D'Orbigny had 

 previously suggested itl for the Lias Ophiura inillleri, Phillips • 

 but, according to Zittel,§ even D'Orbigny's name is in part a 

 synonym of Ophioderma, M. ifc T. No other reference to this 

 double use of Paloiocoma, except that of the late Dr. Thomas 

 Wright, Jl has come under my notice, not even in Dr. B. Stiirtz's 

 excellent review of "Fossil and Living Starfish."^ 



Under these circumstances, and with the object of avoiding 

 this confusion, I propose to substitute the name Sturtzaster for 

 that of Paheocoma, Salter, in honour of Dr. B. Sturtz, of Berlin. 

 To the present fossil I propose applying the specific name of 

 mitchelli, and if therefore it be correctly referred to Palceocoma 

 in the first instance, in the future it must be known as Sturtzaster 

 mitchelli. 



The specimen is from the Upper Trilobite bed of the Wenlock 

 Series at Bowning, N.S. Wales. 



In 1880, the late Prof. Alleyne Nicholson and the Writer pro- 

 posed** the genus Tetraster to take the place of Palceaster, Salter 

 {non. Hall), Salter's conception of this genus being antagonistic to 

 Hall's later definition. ff More recently Dr. Sturtz has proposed,! J 

 apparently for a similar reason, the name Salteraster in the same 

 sense, and to which the date 1886 is attached; it is clear that our 

 name has precedence. 



* Brit. Pal. Foss., Fas. i., 1851, p. 59 ; Salter— Anu. Mag. Nat. Hist., 

 (2), XX., 1857, p. 327. 



t Salter— Brit. Assoc. Report 1856 (1857), pt. 2, p. 77; Aun. Mag. Nat. 

 Hist., (2), XX., 1857, p. 327. 



X D'Orbigny— Prodrome, 1850, i., p. 240. 

 § Zittel— Handb. Pal. i., Abtb. 1, p. 445. 



II Wright— Mon. Brit. Foss. Echinod. Oolitic Form., ii., 1, 1863, p. 29 ; 

 lUd., ii., 2, 1866, p. 143. 



% Sturtz— Verhandl. Nat. Vereins Eheinlande, L., 1893, p. 1. 

 ** Mon. Sil. Foss. Girvan in Ayreshire, 1880, pt. 3, p. 324. 

 tt Hall— 20th Ann. Report N. York State Cabinet Nat. Hist., 1867, p. 

 282. 

 itl Sturtz— Verhandl. Nat. Vereins Eheinlande, L., 1893, p. 42. 



