148 BRITISH PALAOZOIC SPONGES. 
washing his specimen, and which were supposed to have been incorporated in its 
fibres, were most probably derived from the débris infilling the interspaces between 
the fibres, and did not form part of the fibres themselves. In Dr. Hunter’s type 
specimen of H. Armstrongi, the interspaces between the fibres were similarly filled 
with spicules and other débris ; but in none of the specimens which have come 
under my notice is there any structural connection between these extraneous 
spicules and the fibres. 
At the time of describing Haplistion fractum I had not seen an authentic 
specimen of H. Armstrongi, but a comparison with those forwarded to me by Dr. 
Hunter and Mr. J. Smith leaves no doubt that the fragments I named belong to 
Messrs. Young’s species. 
Distribution.—Carboniferous. Upper part of Lower Limestone series: Cun- 
ningham Baidland, Law Quarry, Dalry, Ayrshire. 
29. HaplisTION VERMICULATUM, Carter sp. Plate V, figs. 2, 2 a. 
1878. RuapPHipHistra VERMICULATA, Carter. Ann. and Mag. Nat. Hist., ser. 5, 
vol. i, p. 140, pl. ix, figs. 15—19. 
1883. — — Hinde. Cat. Foss. Sponges, p. 208. 
Small, depressed convex, or irregularly rounded Sponges, apparently free. 
The type-specimen is 12 mm. in width. The fibres either anastomose irregularly, 
or in some specimens are vertical with transverse connections. At the surface 
they terminate in blunt conical processes. The fibres vary from °67 to ‘9 mm. in 
thickness. As in the preceding species they are solid, and are composed of 
straight and slightly curved spicules, which are interlaced with each other. A 
fairly long spicule measures *3 mm. 
The typical specimen described and figured by Mr. Carter, now in the collection 
of Mr. J. Thomson, who kindly forwarded it to me for examination, is depressed 
convex, with a flattened basal portion, which appears to me to be, in part at least, 
a fractured surface, but which Mr. Carter regards as a continuous membranous 
attachment, now lapidified. Mr. Carter further described the fibres as belonging 
probably to a fossil example of Hydractinia on which the Sponge was parasitic. 
It seems to me, however, more probable that, as in H. Armstrong, the fibres of 
this species were throughout composed of interlacing acerate, siliceous spicules, 
which are now, with the exception of those weathered out on the surface, indis- 
tinguishably fused together. I do not think the fibres were originally hollow as 
stated by Mr. Carter; the cavities in them appear to result from erosion. The 
spicules in the type-specimen, as well as in others sent to me by Mr. J. Smith, 
