June ], 1869.] 



HARDWICKE'S SCIENCE-GOSSIP. 



131 



poda. The lack of branchia is against its belonging 

 to Crustacea; while if those long tortuous canals 

 are indeed respiratory (as you call them), they look 

 more like the tracheal apparatus of Insecta. But 

 then the limbs— no insect has more than six; no 

 crustacean more than fourteen; but here are six- 

 teen. The structure wnich you describe in these 

 organs reminds one much of the organs called pro- 

 legs in most of the Lepidopterous larvse, especially 

 in the circle of little hooks surrounding the ex- 

 tremity; but this analogy is belied by everything 

 else in the creature. The anal (or cloacal) orifice, 

 situated just where it would be in a lizard, with a 

 long-developed tail behind it, is totally unlike any- 

 thing I know in the Annulose classes. 



Altogether the creature is most puzzling. I in- 

 cline to think it is a larval or immature state of 

 some animal in this great division ; but I cannot 

 conjecture what are its affinities. As you intend 

 getting more specimens, if possible, I recommend 

 that you (or if transmission alive so far is out of the 

 question, some one at the spot) should endeavour 

 to keep them alive in the native water till either the 

 transformation occur, or it be disproved. 



Of course all that I have said above rests on the 

 traced sketch. Possibly if I saw a specimen I 

 could speak more positively ; at all events, certain 

 points could be tested on which there is at present 

 no evidence. 



The occurrence of an Artemia in the Salt Lake is 

 very interesting : are you quite sure the species is 

 identical with our A. salina? There is another 

 species found iu Algeria,— A. Oudnayi. 

 Believe me, &c, 



P. H. Gosse, E.R.S. 

 S. A. Briggs, Esq., 

 Chicago. 



ERESH-WATER POLYZOA. 



THE writer of the article on "The Wheel 

 Animalcule" in the May number refers to 

 " the statement of a correspondent, in the ' Annals 

 of Natural History,' to the effect that he never 

 failedto stock his aquarium with fresh-water polyzoa, 

 if he obtained for that purpose the statoblasts on 

 some fine winter's day or early in the spring, but 

 could not succeed with the mature animals." 



I have had no difficulty in stocking with the 

 mature animals in case of Plumatella repens, which, 

 in May last year, I took from a pond at Tipton, and 

 placed in my aquarium. They were" attached to stones 

 in considerable numbers. They continued in perfect 

 health during the whole of the summer and autumn, 

 but as winter approached their plumes gradually 

 disappeared, until at last only dead cells remained. 

 The pond was visited from time to time, and the 

 same changes took place there. The upper sur- 

 faces of the dead cells in the tank soon decayed, 



exposing statoblasts attacked to the stones, in evi- 

 dently the same position they occupied before the 

 death of the parent form. 



On the surface of the water of the tank also 

 statoblasts were abundant ; these are what Pro- 

 fessor Allman designates the ordinary statoblasts, 

 which lie loose in the cell, and ultimately become 

 free. He describes the attached statoblasts as fol- 

 lows : — they " never lie loose in the cell, but are 

 invariably attached to the internal surface of the 

 walls, to which they adhere by means of a peculiar 

 cement. . . . After the decay of the ccencecium, many 

 of these attached statoblasts may be seen adherent 

 to the stone or other object on which the specimen 

 had developed itself, and to which they are now 

 connected in lines through the medium of a portion 

 of the old cell in which they had been produced. I 

 am unable to state whether the origin and destination 

 of the last described bodies is similar to that of the 

 others, and I have not succeeded in witnessing the 

 escape from them of the young." (Monograph 

 Eresh-water Polyzoa, Ray Soc.) 



I have just been so fortunate as to observe the 

 escape of the young from the attached statoblast. 

 In March last I detached from one of the stones in 

 the tank before mentioned a fragment, upon which 

 were two of the adherent statoblasts, and placed it 

 in a zoophyte trough. These were watched daily, 

 and in about three weeks I was delighted to witness 

 the budding forth of a young polyzoon from one of 

 them. When first observed its tentacles drooped, 

 as if they had not yet been expanded, but soon the 

 entire crown was in full activity. I was able to 

 count twenty-four tentacles. It continued attached 

 to its native spot with the valves of the statoblast 

 adhering to its body, "the admiration of all be- 

 holders," for about a week, when it was accidentally 

 killed. 



This directed more watchful attention to tb,e 

 tank, and the pool was again visited. Many of the 

 statoblasts on the stones in the tank were just 

 showing a white tip through the opening valves, 

 and in a few days, by 24th April, several were fully 

 developed; these also, like that in the zoophyte 

 trough, occupied the position of the statoblasts, 

 with one or both valves adhering to the body of the 

 polyzoon. Some brought from the pond, about the 

 same time, exhibited the same changes,', and are 

 now flourishing side by side with the natives of the 

 tank. Charles Ketley. 



Smeihwick. 



British Association.— The meeting for this 

 year will be held at Exeter under the Presidency of 

 Professor Stokes, of Cambridge. The opening day 

 will be Wednesday, the 18th of August next. Great 

 preparations are being made at Exeter to give the 

 Association welcome. 



