138 Mr. H. J. Carter on Sponges from the 
horizontal diameter, and 2 inches in vertical diameter between 
the circumference and the centre, where it is thickest (fig. 1). 
Hab. Marine, associated probably, according to Mr. Thom- 
son, with “ reef-building corals.”’ 
Loc. Arbigland, 14 miles south of Dumfries, on the Solway 
Firth, Scotland, 8.W. In dark grey shale interstratified with 
thin bands of limestone characterizing the upper part of the 
Lower Limestone series of the Carboniferous system. 
Obs. On account of the presence of the spicules above de- 
scribed, presenting themselves throughout the fossil s¢dewise 
in the vertical section and endwise in the large excavation, 
which would be tantamount to a horizontal section, there can 
be no doubt that this is a fossil sponge, and, on account of the 
spicules being of one form only and of different sizes, as above 
mentioned, that the sponge belonged to my order Holorhaphi- 
dota and family Renierida, where it would, according to its 
spiculation, come in well with the first group, viz. Amorphina, 
and the species Halichondria panicea, whose spicules in the 
deep-sea form &c. (‘Ann.’ 1876, vol. xvi. p. 470), where 
they are larger than in the shore one so common on our 
coasts, are almost identical. It may also be inferred from 
the spicules appearing abundantly and longitudinally in the 
vertical, while they are seldom seen in the horizontal section, 
together with the broken ends themselves in the large excava- 
tion, that the direction of the spiculation was more or less ver- 
tical. ‘This would have been more satisfactorily confirmed 
could the transverse section of the bundles have been seen in 
the horizontal section, as they thus appear in Pharetrospongia 
Strahant, Soll.; but the opaque crystallization of the calea- 
reous material in the “ granules ” seems to obscure this, since 
the transverse sections of the scattered spicules in the large 
excavation, where the crystallization is transparent, are plain 
enough, with acommon lens of two inches focus: and under a 
magnifying-power of 100 diameters, their axial canal respec- 
tively is distinctly seen, which does not exist in the spicules 
of the Calcispongiz, except in Hiickel’s fertile imagination. 
For the deep-sea variety of Halichondria panicea I have 
proposed the specific name of ‘ cancellosa”’ (/. c.), from its 
areolar structure; and it may be that the “granules” of Pul- 
villus Thomsonii represent such spaces (fig. 2). 
Of course the pores of this sponge have disappeared, from 
their minuteness and situation in the dermal sarcode; while 
the excretory canal-system seems to be indicated by the vena- 
tion between the granules, which in its widest and most dilated 
parts may, in the section, be observed to be filled with hetero- 
geneous material composed of sand and the remains of organic 
