014 E. Thurlow Leeds—On Metriorhynchus. 
certain plates apparently distinct from the ambulacrals, and certainly 
distinct from the spine-bearing plates. Is it not, however, the case 
that the spiniferous elements are themselves the adambulacrals, 
and that the elements to which Mr. Chapman applies the term 
‘adambulacral’ are really processes of the ambulacrals, separated 
from the ambulacral body by a slight depression? Compare my 
interpretation of Bundenbachia, Grou. Mac., 1905, p. 164, Pl. VI, 
Fig. 5). If, however, this interpretation be correct, then the ambu- 
lacral ossicles of Sturtzwra leptosoma and S. leptosomoides are really 
boot-shaped, as in the typical Protaster. 
Until someone undertakes a comprehensive revision with proper 
diagnoses, it will save confusion to retain under Protaster all the 
species here mentioned. None of them, not even P. diforis, seems to 
me congeneric with P. Sedgwicki, the genotype of Protaster. It may 
well be that a subsequent reviser may separate P. brisingoides with 
P. biforis as one genus, and P. leptosoma with P. leptosomoides as 
another. In that event, the former genus will of course resume the 
name Sturtzwra. 
Mr. Chapman also establishes a new genus Gregoriura, with geno- 
type G@. Spryi, for a Protasterid with triangular ambulacrals, of which 
the three proximal pairs embrace the mouth-frames. A slender bar 
extending transversely from the outer point of each ambulacral is 
called an ‘adambulacral’ by Mr. Chapman; there are also spine- 
bearing plates. I would suggest that these elements might be 
interpreted in the same way as those in ‘ Sturtzwra’ are interpreted 
above. This would not affect the validity of the genus. 
It may be worth while to remind English geologists that in 1899 
Mr. R. Etheridge, jun. (Rec. Austral. Mus., vol. ii, pp. 128, 129; 
17th April), proposed the name Sturtzaster to replace the name 
Paleocoma, which Salter had applied to a starfish from Leintwardine. 
Paleocoma had already been used by d’Orbigny in 1849. 
May one, without offending several people of importance, express 
a hope that the future namer of Paleozoic Ophiurids will endeavour to. 
avoid such combinations as ‘‘Mr. Spry’s Gregory-tail”’ or ‘‘ Mr. Stiirtz’s 
tail shaped like Mr. Lightbody”? Whether the object aimed at be 
humour or euphony, few will seriously consider that either is attained. 
V.—Nores on Merrroruayncuus superciziosus, Dest. 
By E. Tuurtow Lzeps. 
Hisar commonest species of the genus etriorhynchus occurring in 
the Oxford Clay of the Peterborough district is Metriorhynchus 
superciliosus (Desl.). The species found in the above locality has 
been identified with that of Deslongchamps by the late Mr. J. W. 
Hulke, F.R.S., in his paper ‘‘ On the Skeletal Anatomy of the 
Mesosuchia”’ (Proc. Zool. Soc. London, November 20th, 1888), and 
also by Mr. Lydekker in the ‘Catalogue of Fossil Reptilia and 
Amphibia,” part iv, Suppt., p. 232. Mr. Lydekker, at the time he 
compiled the Catalogue, brought a cast of part of the skull of I. super- 
ciliosus to compare with the numerous skulls in the Eyebury Collection. 
ret a 
