Carboniferous of the S.W. of Scotland. 129 
fast (vol. xx. p. 176), since which Prof. J. Young and Mr. 
J. Young have conjointly published an account of the sarco- 
hexactinellid sponge to which I have therein alluded, under the 
name of ‘ Hyalonema Smithii” (‘ Annals,’ vol. xx. p. 425, 
pls. xiv., xv.). Their right of priority is undisputed; at 
the same time my promise to Mr. Thomson, F.G.S., to 
describe his fossils must now be fulfilled. 
It is not, however, necessary for me to do this at length with 
Hyalonema Smithi2, as this has already been done (J. c.) ; hence 
what I have to state will be chiefly confirmatory of what has 
gone before, having from the commencement, viz. Sept. 1876, 
been plentifully supplied with fragmentary remains of its 
accompanying spicules by Dr. J. Millar, who obtained them 
from Mr. J. Armstrong of Glasgow, in addition to the speci- 
mens subsequently sent me by Mr. J. Thomson of the same 
city. Mr. Armstrong obtained these fragmentary remains, 
which in many instances are nearly perfect spicules, in great 
numbers from the rotten detritus with which the crevices of 
the limestone where Hyalonema Smithit abounds are filled ; 
hence my figures must be regarded as partly restored. 
Besides Hyalonema Smithii, Mr. Thomson has sent me 
specimens of other fossil sponges from the same system, viz. :— 
one for which I propose the name of “ Pulvillus Thomsonti,” 
from Arbigland ; and two others, which will be named respec- 
tively “ Dysidea antiqua” and “ Rhaphidhistia vermiculata,” 
from the same beds as the Hyalonema. These will now be 
described and illustrated successively. 
Hyalonema Smithii, Y. & Y. 
Of this sponge the separate spicules which I possess were 
furnished, as before stated, by Dr. Millar; and those which 
appear to belong to Hyalonema Smithii have been identified 
in situ through specimens supplied by Mr. Thomson; while 
there are others which appear to have belonged to other species 
of the Sarcohexactinellida, as will be seen hereafter. 
Of the cord or stem three fragmentary specimens have been 
sent to me by Mr. Thomson, two of which are about the same 
size and also close together in the same piece of limestone. 
The largest is five inches long and about one inch wide by one 
sixth of an inch thick, composed of spicules, once long and 
continuous, but now much fractured transversely, indeed com- 
minutely in some parts; varying in diameter from one twenty- 
fourth of an inch downwards and presenting distinct although 
slight undulation (Pl. 1X. fig. 1). Moreover the cord is coin- 
pressed so that in the end view from which the proximal or 
upper portion has been broken off, and it has thus become ex- 
