Mat 1, 1866.] 



SCIENCE-GOSSIP. 



105 



other locality known to me is so rich as this in 

 the particular objects under notice. The sub- 

 stances to which the Serpuke adhere are stones ; 

 old shells, both bivalves and univalves ; broken or 

 whole wine or beer bottles, — these bottles, espe- 

 cially, are very full of various things, both inside 

 and out, — and broken crockery. Not merely Serpula 

 of two or three species are on these masses, but 

 several species of Sabelke, and other tubiculous 

 worms, such as Spio, TerebelUe, and others; and 

 adhering to them, in considerable abundance, are 

 small sea-cucumbers (Oaius), and within the empty 

 univalve shells, such as those of Buccinum, are fre- 

 quently found specimens of a somewhat rare vermi- 

 form echinoderm, Syrinx Harveii. But the great 

 value of these dredged masses does not consist 

 merely in what is found upon them when first got, 

 but also in the highly-interesting things which will 

 grow upon them, from germs not at first seen, when 

 they are properly treated in an aquarium. Here I 

 have one large tank, of 300 gallons capacity, with a 

 stream of sea-water running through it day and 

 night, at the rate of 100 to 500 gallons per 21 hours, 

 according to circumstances, and which is stocked 

 mainly with Weymouth Serpula:, and other creatures 

 naturally associated with them, or grown here on 

 the same masses : I even grow Alcyonium on them. 

 The animals, however, which spring up with greatest 

 vigour in confinement, attached to the same stones, 

 shells, and broken glass and crockery, are Tunicated 

 Mollusks, of various sizes. These are without any 

 shell, but are covered with a leathery tunic, — hence 

 their name. Some of those I grow are of the simple 

 or solitary kinds, i. e. which are not organically con- 

 nected in masses, like the compound species, and 

 look, as they stand up, permanently fixed to foreign 

 bodies by their base, like miniature semi-transparent 

 double-necked bottles. (See Hardwicke's Science 

 Gossip for February, 1866, pp. 30—32.) These are 

 Ascidians, and iu the Serpula tank No. 6 of this 

 establishment, and in all other tanks where Ser- 

 puke are contained, they swarm by hundreds, nearly 

 all of them having made their appearance in situ ; 

 and these specimens are much cleaner, and are 

 therefore better for examination, than those ob- 

 tained grown in the ocean. The simple kinds I 

 mostly grow are, — Ascidia virginea, A. mentida, 

 Molgula tnbulosa, Cynthia quadrangularis, C. gros- 

 sularia, and others ; and the compound kinds 

 which spring up are of two species, namely, Botryl- 

 lus polycyclus and Clavelina lepadiformis. The Bo- 

 tryllus comes in patches, in twenty or more places 

 at once ; and it looks like groups of brilliantly- 

 coloured violet stars set in firm jelly of a darker 

 hue, and after a time it goes away. I have reason 

 to suppose that excess of light is one great cause of 

 their disappearance, for the only colony I now 

 (February 1st, 1866) possess (and which I have pre- 

 served all last summer, after all the rest went away 



in the spring) covers a surface of Portland cement 

 in a corner of a tank which has been purposely, 

 for another purpose,* closely covered by a board. I 

 have often obtained Botryllus from the sea, but 

 have never been able to keep it long ; and I remem- 

 ber that, about twelve years ago, after many at- 

 tempts were made to acclimatise it in the Regent's 

 Park aquarium, London, a great patch, larger than 

 one's hand, and containing several hundreds of indi- 

 viduals, made its appearance, unbidden, on the slate 

 end of one of the tanks. 



Clavelina comes similarly in great colonies, chiefly 

 in spring and early summer, standing up like groups 

 of little clear vases, much less opaque than when I 

 obtain them from the sea ready grown, and less 

 liable to die. But, whether grown or introduced 

 as adults, they disappear after a time, being killed 

 off, as I believe, by the great enemy of most of these 

 beings, light. Clavelina is small enough to be placed 

 j iu a zoophyte trough on the stage of the compound 

 i microscope, and the circulation of its fluids produces 

 a beautiful spectacle, which is figured in one of the 

 ■ plates to Mr. Gosse's book, " Tenby ; a Seaside 

 j Holiday." 1856. I should mention that the two 

 ! compound Ascidians named do not commonly grow 

 ' upon the Serpula masses, like the simple kinds, but 

 rather through their influence ; not only because 

 of the germs introduced with or upon them, but 

 because, as well, of the healthy influences of the 

 numerous forms of alga also growing upon them ; 

 and their roughness of surface, or some other con- 

 ditions, seems peculiarly adapted for encouraging 

 the growth of other kinds of seaweeds, so that our 

 Serpula tank is eminently a very healthy one, not 

 easily put out of order, and with its water ever 

 i brilliantly clear. Sponges, too, like the Ascidians, 

 i are things which are not easily kept when intro- 

 duced in aquaria when ready grown ; but they may 

 be maintained for long periods when they grow up 

 by chance ; and upon the Serpuke masses here, or 

 in the Serpula tank, I have now growing (and bred 

 here) five or six species in a state of great vigour, 

 as, e.g., Sycon ciliatum, Cliona celata, Grantia bo- 

 tryoides, Halichondria panicea, Leitconia nivea, and 

 two others which I cannot name from any books in 

 my possession. Some one, in Hardwicke's Science- 

 Gossip, a little time ago, asked how to keep the 

 Freshwater Sponge [Spongilla fluviatilis). I do not 

 know, as I have often tried, and always failed ; but 

 here, at any rate, is evidence that the dredged 

 masses I am writing of, will, if placed under favour- 

 able conditions, produce many things, and, among 

 others, marine Sponges. At the Birmingham meet- 

 ing of the British Association, last summer, I saw 

 reported in the Athenaum, that Mr. W. R. Hughes 



* February 25th. I have just discovered another small 

 colony, on the under part of the shell, of a large living spider- 

 crab — Mni a Squinudo. 



