160 



• KNOWLEDGE ♦ 



[Sept. 7, 1883. 



not anticipate matters here. We may merely remark that 

 the presence of thread-cells detected Ijy Eimer* in certain 

 sponges (Eenieridtr) helps largely to support these con- 

 clusions. 



Before we leave the subject of the sponges let us look a 

 little more in detail at one of the beautiful siliceous forms 

 {Eitplectella), which finds so deservedly attractive a place in 

 the Exhibition buildings. The first specimen of this sponge 

 was brought to this country from the Philippines for the 

 Zoological Society, and was carefully described -with figures 

 by the distinguished Director of the British ^Museum in 

 the "Transactions" of that Society. t Dr. Owen sup- 

 posed that the upper broad end was buried in the sea 

 bottom, and that the smaller extremity, with its tuft of 

 fibres, was its upper free portion. It is now known that 

 the reverse of this is actually the ease, and that the 

 fibrous narrow extremity anchors the sponge to the sub- 

 stratum. In Lady Brassey's case there are also a few 

 examples of another beautiful sponge, commonly known 

 as the glass-rope .sponge (Ili/alonema), and, strange to re- 

 late, it also was long represented upside-down, with its 

 glassy rope of siliceous fibres spreading out above, instead 

 of serving to fix the sponge to the bed of the ocean. 

 Both of these lovely organisms, Euplectella and Ilyalonema, 

 belong to the same group of siliceous sponges, the Ilexac- 

 tinellida; so called because their spicules are primarily six- 

 rayed. 



Circumstances of great interest to naturalists may l)e 

 observed in l>oth Euplectella and Hyalomma. In the former, 

 it often happens that the body-cavity contains species of 

 curious crustaceans, and it was thought that the poor little 

 creatures were "the insects" which produced the exquisite 

 .sponge. The presence of the crab within the body-cavity 

 of the sponge, however, serves to illustrate a very peculiar 

 and important occurrence in Nature, known as com- 

 mensalism. The crab does not live at the expense of the 

 sponge, and is not therefore a parasite ; it merely lives 

 ivith the sponge at a place best adapted to the provision of 

 its wants. It commenced its existence within the sponge 

 as an egg or young animal taken into the body-cavity with 

 other food ; instead of being digested, it survived, and 

 grew there into an adult crab, living upon materials 

 brought to it by the sponge ; it received all the necessary 

 wants of life in a comparatively secure retreat, and trans- 

 mitted the peculiarities, whereby it was enaViled to survive, 

 to its offspring, fitting them to take up their abode within 

 the same or some other Euplectella. Here we have an ex- 

 cellent example of the survival of the fittest. Now, if we 

 look at Hyalonema, we shall observe in most specimens 

 that the glassy rope is covered over with a brown incrusta- 

 tion. When perfectly fresh, this outer brown coating is 

 resolvable into a number of closely adherent sea anemones 

 of the genus Palythoa. To Palythoa the fabrication of the 

 sponge was once attributed ; but careful researches into its 

 structural i-elations has shown that Palythoa, like Euplec- 

 tella's crab, is only a commensal. 



For many years Venus's flower-basket was considered to 

 be a very rare organism, and found a place only in the 

 cabinets of the wealthy ; specimens can now be procured 

 at from four to ten shillings each. The demand for speci- 

 mens made the fishermen of the Philippines very zealous 

 about concealing their hunting-grounds, and Professor 

 Owen, in descriliing the capture of the type specimen, J said 

 that it was reported to have been obtained off the island of 

 Bohol, at a depth of ten fathoms, and on a rocky bottom. 



All subseqiient experiences show that Euplectella lives only 

 on a soft muddy bottom, at depths, according to Captain 

 Chimmo, of from 120 to 140 fathoms.* In the voyage of 

 the Challenger, numerous examples were procured off the 

 island of Zebu, at from 95 to 100 fathoms, and only one 

 solitary form [Euplectella suherea), with fragments of others, 

 have been described liy the late Sir Wyville Thonisonf as 

 coming from a depth of 1,090 fathoms in the Atlantic 

 Ocean, ninety miles south-east of Cape St. Vincent. 



* " Nesseizellen und Saamen bei See-Schwammen," Arch, fiir 

 Mik. Anat., Bd. viii., 1872. 

 t Vol. iii. 18-11, p. 203. 

 X " Transactions of the Liunaean Society, 1857." Vol. xsii. 



The American Granite Cutters' Journal says : — " From 

 surveys and calculations made by Mr. J. A. Farrington, 

 civil engineer, the famous Washington boulder, near 

 Conway Corner, N. H., is found to measure 30 ft. in height, 

 46 ft. in length, 35 ft. in width, and to weigh 3,867 tons. 

 This is the largest known isolated piece of granite in the 

 world." 



The Washington correspondent of the Cleveland Leader 

 writes : — " The Washington monument is the wonder of 

 Washington, and its beauty the admiration of both 

 Americans and foreigners. Already over 350 ft. high, it 

 rises from the banks of the Potomac a great white marble 

 shaft, piercing the clouds, and backed against the blue of 

 the sky. It is already the grandest obelisk the world has 

 ever seen, and in the a>ons of the future, should the nations 

 of the day pass awaj', leaving no more records of their pro- 

 gress than the mighty ones of the Egyptian past, it will 

 surpass the Pyramids in the wonder of its construction. It 

 is already higher than the Third Pyramid, and within 

 100 ft. of the size of the second. It is taller than St. Paul's 

 Cathedral, and when finished it will be the highest struc- 

 ture in the world." 



Sport and Science. — Medical science has for centuries 

 experimented on live animals for the purpose of obtaining 

 increased knowledge of the laws of health and disease in 

 the human body. That often unnecessary researches of 

 this kind have been prosecuted is probable enough ; and, 

 unfortunately, it is but too certain that many who have, 

 perhaps, begun such researches with no other wish but to 

 extend knowledge, have grown not merely callous but 

 cruel. In other words, it is certain that the practice of 

 vivisection, which is a very old practice, has been subject 

 to abuses. Yet the legislation by which medical researches 

 conducted on the bodies of living animals have been re- 

 stricted, has not altogether commended itself to the approval 

 of men of science. In this country most of the restrictions 

 were not required, and were little short of insults to the 

 medical profession. Some of the restrictions also have proved 

 mischievous in their operation. Be this as it may, it has 

 been shown that the Legislature can deal with the wrongs 

 of animals when only the researches of a learned profession 

 are in question. It is otherwise when the sports by which 

 our idlers amuse themselves are involved. The wretched 

 sport of pigeon-shooting, as worthy of support as the street 

 lout's practice of flinging stones at cats and dogs, receives 

 protection from the House of Lords Temporal and 

 Spiritual ; the latter indeed not positively voting in favour 

 of the right of grown men to shoot at wretched half- 

 winged pigeons, but by carefully abstaining from voting 

 serving equally well the purpose of the wretched beings 

 who find sport in pigeon-shooting, whether in the cruel 

 work itself or in looking on at it. — Mr. R. A. Proctor in 

 the Neivcastle Weekly Chronicle. 



* "Natural History of Euplectella axpergillum." By William 

 Chimmo. (London. 1878.) 



f " Voyage of the Challenger, — The Atlantic," Vol. i., p. 133. 



