256 | Mr. H. J. Carter’s Contributions to our 
family Suberitida of the order Holorhaphidota (No. 23, 
pp. 182 and 184), there is a thick cortex composed of elastic 
tissue (charged, of course, with the spicules of the species), 
so densely developed that in consistence it is almost semi- 
cartilaginous, with no “ evident skeleton ;” while the same 
sponge, as before stated, grows here over shells in the form of 
an incrustation in which hardly more than the cortical layer 
is developed, thus simulating Schmidt’s Columnitis squamata 
so closely that I cannot help thinking that one and all must 
be the same, and that therefore, if Columnitis squamata is, 
according to Schmidt, to be placed among his Gumminee, 
Donatia lyncurium also ought to come under our Gumminida. 
That Donatia (originally called “ Tethya” by Lamarck) has 
no specific alliance whatever with Tethya cranium, Johnston, 
which is the type of my group ‘“ Tethyina,” may be easily 
seen by an examination of both species. Hence there seems 
no reason whatever why Donatia should not join Columnitis 
squamata among the Gumminida; so it may fairly be inserted 
in my tabulated enumeration of the Carnosa, p. 252, antew. 
It would have been satisfactory to have had a description of 
the form of the skeleton-spicule of Columnitis squamata in 
the text as well as in the illustration, in which the anteterminal 
inflation makes it differ from that of Donatia lyncurtum ; but 
in the Polymastina, which, not only in the tender but in the 
compact and hard forms, are in spiculation closely allied to 
Donatia (No. 25, p. 892), the head of the spicule constantly 
varies, even in the same species, between a simple fusiform 
acuate and an anteterminally-inflated shatt. 
Lastly, in Axos spinipoculum (No. 28, p. 286, pl. xxv. 
figs. 1-9) there is an unusual development of the elastic tissue 
in the cortex as well as about the excretory canal-system (J. c. 
figs. 6-8) ; so that, but for the presence ot an “ evident skele- 
ton,” dendriform and spiculo-fibrous, it also, would be placed 
among the Carnosa instead of the Holorhaphidota, where, 
perhaps, after all it should form a distinct genus in the group 
Axona (No. 32, p. 881). I mention this imstance chiefly to 
show that the elastic tissue may be developed to a great extent 
in sponges which, possessing in addition an “ evident skele- 
ton,” cannot therefore be admitted into the order Carnosa, 
The soft, slippery, velvet-like dermis of the common black 
sponge of this coast, named Dercitus niger by Dr. Gray, and 
described by myself (No. 14, p. 3, pl.iv. figs. 1 &c.),= Hyme- 
niacidon Bucklandi, Bk., of 1866 (No. 6), =Battersbya 
Bucklandi, Bk., of 1874 (No. 21), =Lachastrella, Sdt., of 
1868 (No. 9), aptly compared by Dr. Bowerbank to “ bullock’s 
liver’ when fresh, i which the elastic tissue is powerfully 
