158 



HARDWICKE'S SCIENCE-GOSSIP. 



[July 3, 1SG9. 



formed of twigs and fibrous roots, and looks as if 

 a sudden gust would at once scatter all the mate- 

 rials ; but they are so cleverly woven together, and 

 the interior is so compactly lined with fine fibre, that 

 the outside twigs, which appear so loose, are all held 

 firmly in position. 



The eggs are five or six in number, of a pale blue 

 ground-colour, spotted and blotched towards the 

 larger end with purplish brown. Not unfrequcntly 

 these spots are so regularly dispersed over the sur- 

 face as to resemble a crown of thorns. The young, 

 when hatched, are curious little fellows, their heads 

 and bills seeming so disproportionate in size to the 

 rest of the body. They are wonderfully clamorous 

 for food, and the energies of the old birds must be 

 severely taxed in flying to and fro all day with their 

 mouths full. 



We have sometimes felt inclined to leave a Bull- 

 finch undisturbed on a fruit-tree, in consideration 

 of the amends he would ultimately make by destroy- 

 ing insects for his family. But in this case we are 

 not prepared to say that the good would quite 

 counterbalance the evil. "We fear it would not. 

 Nevertheless, we prefer to treat our little friend 

 like a spoilt child, .and would rather miss a few 

 cherries and plums than lose the pleasure of seeing 

 him in the garden and of listening to his cheerful 

 song. J. E. Harting. 



EBAGILLABIA CROTONENSIS (7? Kilton). 

 By E. C. S. Boper, E.L.S., &c. 



N the May number of Science - Gossip some 

 notes appeared by Mr. Kitton on the diato- 

 macere occurring in the water supplied to the city of 

 New York, called, from the river which supplies it, 

 " Croton water," and forwarded by Dr. Edwards to 

 my late friend Dr. Walker Arnott, of Glasgow. 

 Erom samples I have myself received of these 

 Croton-water gatherings, I have no doubt Mr. 

 Kitton is perfectly correct in his determination of 

 the majority of the species that occur, and I fully 

 concur with him in thinking that Asterionella gracil- 

 lima, Hantzsch, is merely what is known here as 

 Asterionella formosa, Hass., or at most a slight 

 variety of that species. But I regret to find that 

 he has been induced to give a new name and specific 

 character to the form called Fragillaria crotonensis, 

 especially as I know lie strongly objects to this 

 l>eing clone without full and satisfactory evidence. 

 At the same time there is no doubt the species of 

 Fragillaria are extremely variable in form, and with- 

 out a very extensive suite of specimens any one may 

 well be led astray. 



Through the kindness of Dr. Arnott and other 

 friends, I have a very complete collection of gather- 

 ings of this genus, including" fifty slides of F. captc- 

 cina and its varieties alone, from various localities ; 



and this very form figured as a new species was 

 one on which I had some considerable correspon- 

 dence with Dr. Arnott only a few months before his 

 death. 



Erom a most careful consideration of all these 

 gatherings, I have no doubt that the form in ques- 

 tion is a Fragillaria, as Mr. Kitton supposes, but it 

 is F. capucina, var. y, of W. Smith's " Synopsis," 

 vol. ii. p. 22, but of which he gives no figure, and 

 states that it has only occurred to him in the Bos- 

 thorn Mere gathering supplied to him by Dr. 

 Arnott. I have a slide of this; and the same variety 

 occurs in another slide from Mr. Hardman, of Liver- 

 pool, and also in one from "Tol'-y-Llyn," in Wales, 

 from my friend Mr. Groves, and in all combined 

 with the true F. capucina. The passage from the 

 typical form to the variety is best marked in the 

 last gathering. 



Mr. Kitton describes his species as "Erustules 

 linear, inflated at the central part, where they cohere 

 and form a ribbon-like filament." Smith describes 

 F. capucina as with "Valves linear," and says of 

 var.y, "Frustule subsilicious, adhering imperfectly;" 

 and in his note on the species he says, " When dry, 

 the frustules in this variety shrink, except in the 

 central and extreme portions, and remain loosely 

 attached by these parts." Erom the slides I have, 

 I agree with Dr. Arnott in thinking that the frus- 

 tules frequently occur quite as strongly silicious in 

 this variety as in the typical form, but it may pro- 

 bably be as Professor Smith suggests, a sporangial 

 state of the species, though Dr. Arnott considered 

 this doubtful; but it certainly is not entitled to rank 

 as a distinct species. 



THE MAY-ELY. 



(Fphemera vulgata.) 



rpilE May-fly has been, historically,' very badly 

 -*- treated, and made appear a much poorer 

 creature than it really is. As children, we were 

 told, on the best nursery authority, that there was 

 a poor gnat that lived a single day and then died ; 

 a story ..which filled our little minds with wonder 

 and pity. It was a relief afterwards to learn that 

 this one day of winged existence was preceded by 

 three years of aquatic life ; but this was qualified 

 by the intelligence that through this long period it 

 lived on mud. Such, indeed, was the assertion of 

 Swammerdam, and this strange opinion, stamped 

 with his great authority, has been received and 

 handed down for more than two hundred years, 

 almost to our own day. Mud was always found in 

 the larva on dissection, therefore it must eat and 

 live on it. Messrs. Kirby and Spence had some 

 misgivings on the subject, and thought it must eat, 

 in addition, decaying vegetable substances. The 

 Bev. J. G. Wood, with his usual sagacity, while 



