130 



HARDWICKE'S SCIENCE-GO SS1P. 



[June 1, 1S69. 



THE CROWN ANIMALCULE. 



I HAVE been very much interested in reading 

 Mr. W. H. Hall's remarks upon Stephanoceros 

 Mchhornii and its allies, and the more so as my 

 experience very much corresponds with his. Some 

 years ago, I kept an aquarium well stocked with 

 fine-leaved water-weeds and a few minnows, chiefly 

 as an adjunct to the microscope. As a rule, it 

 swarmed with Stentors ; but I found, in addition to 

 these, many species of rotifera, vorticcllids, and 

 other animalcules. In the summer of, I think, 1862, 

 in looking casually over a bit of conferva, I found 

 what I had long looked for in vain,— a specimen of 

 the Crown Animalcule. My pleasure in making the 

 discovery was, perhaps, equal to your correspondent's. 

 An occasional dip into the tank rewarded me with 

 other specimens, and I soon found that to catch 

 them was no haphazard matter, for they were clearly 

 perceptible to the naked eye through the plate glass 

 sides, even though situated in the remotest corner. 

 The majority of the specimens (although that de- 

 pended very much upon their age) were extremely 

 fine. Some were so large as to be visible — if favour- 

 ably situated with regard to the light— without 

 artificial aid, at a distance of two feet. I saw them 

 covering the stems and leaves of plants, as well 

 as the sides of the aquarium, in hundreds. To the 

 eye each Stephanoceros looked like a particle of 

 jelly depending from the object to which it was 

 attached, and swayed to and fro with every current. 

 Even the crown, the creature's chief ornament, was 

 visible, like a delicate film, protruding from the 

 apex of the gelatinous envelope. I did not notice 

 the formation of statoblasts. If there were these at 

 any time, they escaped observation. The Stephano- 

 ceri, however, were prolific. Young were rapidly 

 hatched, and, in at least one instance, I observed 

 the escape from the parent of an infant Stephano- 

 ceros, as described by Mr. Gosse {Popular Science 

 Revieic, vol. i. p. 39). They increased and multi- 

 plied throughout the winter, and at no time, so long 

 as I kept the aquarium together (some two or three 

 years), were they altogether abseut from it. Although 

 very many specimens of the Floscule tribe, includ- 

 ing Floscularia ornata, F. campanulata, and F. cor- 

 nuta, were found, as well as Melicerta ringens, there 

 was nothing like a "struggle for existence." There 

 is nothing in the nature of these creatures, so far as 

 I can see, leading to the conclusion that one species 

 is forced out of existence, or supplanted, by another. 

 If it does happen that one species is eclipsed by 

 another, in point of numbers, in any season, the 

 circumstance, I apprehend, is merely accidental. 

 Nor do I think that the food supplied to the fishes 

 had any bearing upon the development, as regards 

 size, of individual Stephauoceri. What I consider 

 of more importance is the aspect of the window in 



which the aquarium is situated. Mine had a north- 

 eastern aspect, and therefore got very little sun. Ro- 

 tifera cannot exist if exposed to the burning rays of 

 the sun, in a glass vessel, as they would be if placed 

 in a window with a southern aspect. Nor is such a 

 situation favourable to any kind of animal or plant 

 life in an aquarium. I therefore attribute the 

 failure of any attempt to stock aquaria with tube- 

 dwelling rotifers more to the improper situation of 

 the vessel than to the fact of their being introduced 

 in the fully-developed form. The disappearance of 

 a certain species of animalcule, which may for a 

 time have been abundant, is to me quite unaccount- 

 able. It is, nevertheless, a fact that they do disap- 

 pear. Stentors seem particularly liable to these 

 mutations. One winter my aquarium was literally 

 overloaded with Water-bears ; but on the approach 

 of spring they gradually died off, and I have never 

 seen one since. J. C. 



16, Ellesmere Place, Stockport Road, 

 Manchester. 



CURIOUS ANIMAL FROM SALT LAKE. 



THE following is the reply of P. H. Gosse, Esq., 

 E.R.S., to the letter published in Science- 

 Gossip for April, p. 79 :— 



Sandhurst, Torquay, Feb. 17, I869. 



My deah Sir, 



I am very much obliged by your courtesy in 

 sending me the duplicate sketch of your strange 

 animal from the Salt Lake, and the fuller particu- 

 lars of its known history. I wish I could give you 

 any information of value regarding it; but I am 

 utterly at a loss to what place in the Systema 

 Naturce to refer it. 



There appears to be no indication of a vertebral 

 column ; or else I had mused whether it were the 

 larval or tadpole condition of any unknown Batra- 

 chian. We may then consider it invertebrate. The 

 pairs of limbs furnished with claws seem to exclude 

 Molhisca, as does the absence of branchia or lungs. 

 The bilateral symmetry of the animal eliminates the 

 Radiate forms, and the Protozoa are manifestly out 

 of the question. 



Thus the creature must, I think, be referred to 

 the great division Annulosa; but to which of its 

 classes ? The size, the absence of a mastax, of 

 rotatory cilia, the number and position of the limbs, 

 exclude the Rotifera. The form of the body, of 

 the limbs, of the respiratory vessels, exclude the 

 Annelida. Myriapoda and Arachnida need not be 

 considered. There remain Crustacea and Insecta, 

 and to these I suspect it will prove to belong. Yet 

 everything suggests that not the perfected, but the 

 larval condition is thus presented. The absence of 

 segments in the body, and of joints in the legs, is 

 against its being a fully-developed form of Arthro- 



