Miscellaneous. 257 



increase our latitude, it would seem probable that we are traver- 

 sing their smallest diameter, as it is most likely that they would 

 spread in the direction of the latitude, and it is then easy to com- 

 prehend what a vast extent of surface they must cover, and the count- 

 less multitude of the individuals. The temperature of the water to- 

 day is 59°, the air remaining at 65°. — 28th. The Anatifa ceased as 

 above. The Velella still continues, and are generally very line spe- 

 cimens. We have travelled eighty miles since midday yesterday and 

 have not missed them. Some BeriJe are among them. The Anatifa 

 has partially reappeared, but is scarce. I have also discovered a group 

 of them attached to the skeleton of a Velella : they have evidently 

 been here a long time, as some had attained a good age. — '29th. The 

 Velella ceased last night, having continued around us for 101 miles. 

 Yesterday we passed through a compact bed of them, which at a di- 

 stance had a hne grass-green colour. 



On July 27th, when going to the southward, in lat. N. 47° 54', long. 

 W. 127° 1', we passed through the same Velella for several miles, 

 though not so numerous as on the previous occasion. — Hinds, MSS. 



CECONOMY OF THE WHALE. 



To the Editor of the Annals of Natural History. 

 Sir, — The following questions have, I believe, been only imper- 

 fectly answered by physiologists. How does the Whale support the 

 immense pressure he must bear at the depth in the sea to which he 

 often dives } and what is the end to be answered by the blow-holes 

 on the back of his head ? It appears to me that both questions may 

 be solved by one short answer, viz. he permits the water to enter his 

 lungs as he dives to balance the pressure without, and spouts it out 

 through the blow-holes by the aid of the air which expands in the 

 lungs as he rises ; the jet of water would impede his rising were it 

 to pass from his mouth. — Yours, &c. J. D. C. Sowerby. 



NOTES ON SOME LIBELLUL^E. BY J. C. DALE, ESQ., F.L.S. 



In your last Number (LVL), p. 1 63, reference is made to the figure 

 of the wing of a fossil Dragon-fly found in Warwickshire, Mag. N. 

 Hist. vol. iv. New Series, p. 302, as the jEshna liassina, Strickl., 

 where the wings oiJEshna grandis and Libellula depressa are also given 

 to show the difference in size and structure. The stigma on the 

 wing shows it to be nearer to Cordulegaster and still more to Petalura 

 ' Zool. Misc.,' vol. ii. plate 94, where it is stated to be a native of 

 New Holland ; and I have a female of the same from Mr. Children's 

 cabinet, which on comparison bears a close resemblance to the 

 fossil fly. 



I take this opportunity of making known as British the Agrion 

 pumilio, Charj)., having taken specimens in this neighbourhood many 

 years ago ; and although it may be mistaken for a variety of A. ele- 

 gans, Vand. Lind. {tuberculatum, Charp.), at first sight, it is easily 

 distinguished by the absence of the tuljcrcle on the collar, imme- 

 diately behind the head, so conspicuous in that species, and other 



