15° 



HARDWICKE'S SCIENCE-GOSSIP. 



H.M.S. "HYDRA" AND MARINE ZOOLOGY. 



FROM the study of fossil remains, I have recently 

 become greatly interested in natural history. 

 Marine life at present is that to which I devote as 

 much time as a retail tradesman can afford in this 

 co-operative age. 



The littoral zone of the Sheppey coast yields a 

 great variety of microzoa, as well as plenty of larger 

 forms. I do but refer to these now, as I wish 

 ■principally to call attention to the rich zoological 

 harvests that may be gathered from the hulls of 

 vessels when in dry dock. In Sheerness Dockyard, 

 opportunities of this nature often occur, and by the 

 kindness of the resident officials, I have been enabled 

 to observe and search as closely as I pleased. H.M.S. 

 *' Hydra " — a very powerful turreted iron-clad, 

 sometimes irreverently called a "flat iron" — was 

 recently taken into dock here, and I, loaded with 

 bottles and jars, was on the spot when the 50-horse 

 power engine began to pump out. First of all, as the 

 water lowered, I observed that crustaceans and other 

 small fry in abundance were leaving the ship's side 

 and going with the stream, evidently aware that their 

 surroundings were abnormal and that something 

 unusual was about to happen, 



A rough glance at the exposed portion of the hull 

 below the water line showed immense patches of 

 good sized mussels (Mytilus edulis), from amongst 

 which protruded the straw-like horny stems of 

 Tubularia in such quantity as to present somewhat 

 the appearance of a grass meadow scorched by 

 summer heat, or perhaps more nearly that of a 

 stubble-field. The polypites that had formerly 

 crowned each stalk had nearly all disappeared, 

 though it may not be before having thrown off hosts 

 of medusiform buds that had started on their own 

 account as "Jelly-fishes." Still some remained, and 

 it certainly seemed to me to be a fitting arrangement 

 that the " Hydra" should have carried a full comple- 

 ment of Hydrozoa parasitic upon her sides. 



In gaps here and there, and also in places where 

 there were no mussels, I noticed large cakes of mud 

 about an inch thick, that had the appearance of having 

 been kneaded and plastered into position. Looking 

 closer with a lens, I found that this mud was closely 

 pierced with holes. Therefore I concluded that it 

 was inhabited, and consequently put a good handful 

 into a jar with some water to take home for after 

 observation. As I glanced along the ship's side, I 

 noticed a continual waviness, as of something agitated 

 by the wind. This I found was caused by a multi- 

 tude of the singular-looking Caprella linearis, which 

 were holding on by their hind claspers, and swinging 

 their gaunt forms about as if in an extremity of grief. 

 Every spot was alive with them, I put a few hun- 

 dreds into a jar, and they gripped one another so 

 tightly that in a few minutes they were all dead in an 

 almost solid mass. 



Of course there were plenty of barnacles, but 

 being very young they were scarcely to be perceived 

 by the unassisted eye. 



Then there were some very interesting Annelids,. 

 Polynoe being the most abundant, 



A species (probably new) of Phoxichilidium, as- 

 well as some other sea-spiders, were crawling about 

 in their usual lazy way. These creatures, which are 

 really very nearly "all legs and no body," present, 

 in their movements, a very striking contrast to their 

 terrestrial relatives. 



Let me now revert to the mud that I brought away. 

 When it subsided, I found that the water above was 

 crowded with a small species of crustacean, that 

 apparently combined in itself the characteristics of 

 the woodlouse and the shrimp. These then were 

 the creatures that had coated the ship with mud in 

 spite of the patent anti-fouling composition laid on. 

 less than a year before. They must have caught 

 mineral particles floating by and used them in the 

 construction of their homes and hiding-places. I 

 was afterwards confirmed in this opinion by finding, 

 that all of them I put into an aquarium at once made 

 places in which they could hide. 



Some took small filamentous Algae and felted them 

 into a neat tube which they attached to the glass. 

 Others appropriated spaces between pebbles, over 

 which they fastened a vegetable covering in default of 

 anything else to work with. 



In whatever way they were housed, they kept up 

 a ceaseless current with their false feet, and thus 

 obtained all that was necessary to existence. This 

 ship, on which there must have been an almost 

 incalculable number of these crustaceans, had only 

 been out of Sheerness harbour for a few hours since 

 her hull was thoroughly cleaned less than twelve 

 months before. 



In the face of this fact, it is amusing to find it 

 stated by Spence Bate and others that this little 

 creature, identified as CoroJ>hij(m crassicorne, is " a 

 rare species in British seas " ! 



It is remarkable that there was no vegetation, 

 associated with this mass of marine life. I expected 

 to find some diatoms, at least. There is much more 

 that I should like to say ; but perhaps I have written 

 enough to induce some others, who may have the 

 opportunity, to look for themselves. , 



I shall be glad to send specimens of the Caprellce 

 taken from the "Hydra" to any who care to send 

 a tube and a label, with address and stamp. 



W. H. Shrubsole, F.G.S. 

 Shecrness-on-Sea. 



Funeral Plants.— Can any of the readers of 

 Science-Gossip tell me the name of the plant the 

 Jews used to carry at funerals, and to stick in the 

 grave when the burial took place hastily, and whea. 

 the body was not interred in stone ? — E. Edwards. 



