NA TURE 



{^Nov. 5, 1885 



effects of stress on the physical properties of matter lead me to 

 infer that the critical tension will be lower the higher the tem- 

 perature. Herbert Tomlinson 

 King's College, Strand, October 31 



The Resting Position of Oysters 



As your correspondent, Mr. J. T. Cunningham, expresse-; a 

 doubt as to the evidence on which the current belief of concho- 

 logists is founded that oysters rest on the convex valve, I beg to 

 inclose a cluster of three, brought to me among others from 

 Torbay this morning. Th':y are all attached by their convex 

 valves, and confirm the descriptions of Messrs. Woodward, 

 Jeffreys, and Huxley. 



Mr. Cunningham's Sertularia and Thuiaria go to prove that 

 he has seen oysters from the Firth of Forth that rested on their 

 flat valves. This is easily accounted for. Solitary, unattached 

 oysters, resting on the sea-bottom, would easily, from their 

 peculiar form, be turned over by wave-currents (if exposed to 

 them) ; or they might fall on their fiat valves when thrown 

 overboard by dredges as too young for market. In either case, 

 once overturned, tiiey would be powerless to regain their natural 

 position. 



With regard to the Pectens, Mr. Cunningham does not specify 

 the species found covered, as to the convex valves, with Balanus, 

 &c. In two such common sorts as P. maximus and P. opercu- 

 laris, we find in the one the under-valve more convex, in the 

 other the upper valve. In each case the moUusk rests on the 

 same valve. Arthur K. Hunt 



Torquay, October 27 



Salmo salar and S. ferox in Tasmania 



In your issue of October 29 is a communication from Mr. 

 Saville Kent, in which he "concludes that no true salmon has 

 yet been established in the lakes and rivers of Tasmania. The 

 fish of large size which abound in the great lakes and other large 

 sheets of water are really essentially the same as the great lake 

 trout, Salmo ferox, of Great Britain. " 



Respecting the jalmon, although very possibly Mr. Kent has 

 not yet seen a true one in Tasmania, such does not abso- 

 lutely prove their absence. In the Field of last May I drew 

 attention to an undoubted salmon smolt, 9 inches long, which 

 was sent home from Tasmania by Mr. Robins, on January 3, 

 1880, and is now in the national collection. 



As regards the great lake trout, I observed in the Proceedings 

 of the Zoological Society, January 15, 18S4, that the original 

 stock of British fresh-water trout from which ova were procured 

 to send to Tasmania, were solely obtained in Hampshire and 

 Buckinghamshire, localities where the great lake trout is not 

 found, unless it is merely a variety of the brook trout. 



The late Mr. W. Arthur, whose recent death at Dunedin 

 will prove an irreparable loss respecting these investigations, 

 sent me two specimens in ice in July 1883. One was a male, 

 ■yi\ inches long, the other a female, one inch less. I remarked 

 that "these two beautiful specimens of trout are so exceedingly 

 similar to so-called lake trout, that any ichthyologist who be- 

 lieved in the numerous species of this fish, and was unaware 

 from whence they came, would undoubtedly term them Salmo 

 ferox." 



Whether Mr. Saville Kent in the note in question considers 

 the great lake trout, S. ferox, a distinct sjiecies from the brook 

 trout, S. ferio, seems left to the reader to surmise. Should he 

 be correct in his identification (as I believe him to be), then the 

 great lake trout has been raised from the eggs of the small brook 

 trout, showing it to be merely a variety which, under favourable 

 conditions, will attain to a large size. Francis Day 



CheUenham, October 30 



A Right-footed Parrot 



If my memory does not deceive me, Mr. Romanes asked some 

 months ago for an account of any peculiarities shown by parrots, 

 in which case you may be able to find a corner for the following 

 incident : — 



Last Sunday I gave our parrot— an ordinary grey bird— the 

 hardest walnut I could find, as when busy cracking the shell she 

 is less noisy. After struggling for a long time in vain, at first 

 on the perch and then on the bottom of the cage, holding the 

 walnut as usual with tlie right foot, she changed feet, whether 

 because the right foot was tired or not I cannot say ; but now 



utterly failed to make the walnut reach her beak. Time after 

 time the walnut was raised above the bird's head, rather over 

 the neck. At the same time she was unable to stand steady, 

 but fell over and rested on her rijjht wing. After about a 

 dozen fruitless attempts, and by the time every one in the 

 room was shaking with laughter, she flung the walnut down 

 with a shriek and returned to her perch. C. V. Boys 



The New British Myzostoma 



Since recording the discovery of an encysting Myzostoma on 

 the Comatulfe of Milford Haven (Nature, August 27, p. 391) 

 I have examined a large number of oiher examples oi Antedon 

 rosacea from different British localities ; and I have found 

 Myzostoma cysis or other modifications of the pinnule-joints on 

 individuals from Torquay, Cumbrae, Arran, and Oban, while in 

 one or two cases the arm-joints are also affected. Prof. A. C. 

 Haddon has kindly sent me some Comatute which he dredged 

 last summer in Berehaven, County Cork, and in Dalkey Sound, 

 County Dublin, and I have found slightly malformed pinnules in 

 one individual from each locality, though there are no traces of 

 definite cysts. It is clear, however, from what has been said 

 above, that this encysting Myzostoma has a tolerably wide distri- 

 bution in the British area ; and I shall be very glad to hear of 

 its discovery on Comatulae from other localities than those which 

 I have mentioned. 



The cysts are fairly conspicuous on the Cumbrae specimens 

 (dredged by Mr. Sladen), though nothing like the size of those 

 which occur on the Crinoids of more tropical seas ; and I sup- 

 pose that this is the cause of their having so long escaped the 

 notice of the many naturalists who have dredged at this locality. 

 Now, however, that attention has been directed to them, it is 

 quite possible that they may be discovered at Roscoff and at 

 various localities in the Mediterranean, where .Aniedon rosacea is 

 equally abundant. P. Herbert Carpenter 



Eton CoUcsje, October t,i 



Tertiary Rainbows 



The following extract from my journal may be of interest 

 with regard to the subject of "Tertiary Rainbows " : — 



"May 5, 1SS5. — Extraordinary display of rainbows at 4.30 

 p.m. on Grand Trunk Railway between Knigston and Montreal. 

 Six bows in all were seen. The primary was flanked on the 

 inside by four bows quite near, and on the outside at some 

 distance by a fifth." 



The bows were all quite distinct, but of c lurse of decreasing 

 brightness in passing from the primary inward. They were 

 noticed by several persons besides myself. 



W. L. Goodwin 



Queen's University, Kingston, Ontario, October 15 



"Furculum" or "Furcula" 



Dr. Sclater in his letter to Nature (vol. xxxii. p. 466) 

 calls attention to a very interesting point in regard to the use of 

 the wordfiirculiim, asking, as he does so, for its authority. Not 

 only are the eminent anatomists — Balfour, Huxley, and RoUeston 

 — mentioned by him, authorities for it, but the majority of ana- 

 tomical writers, both of the Continent and Great Britain ; they 

 having also lent their influence, through custom, to the intro- 

 duction of this word. In this country the same holds true, and 

 the use of the term furculum for furcula receives the support of 

 such high authority as Marsh (" Odontornithes," p. 58, Fig. 14/) 

 and many others. 



Dr. .Sclater further states that he has failed to find its use 

 sanctioned by any dictionary. For the large dictionaries of the 

 language this no doubt is true, but in quite a number of works 

 upon anatomy that present us with a " glossary of terms," we 

 find the wio\i\ furculum given, and not furcula, as, for instance, 

 see " Elements of Zoology," by M. Harbison, Head Master, 

 Model School, Newtownards, and " Handbook of Vertebrate 

 Dissection," Part II., by Martin and Moole. More than this, 

 furculum is the only word given in certain scientific dictionaries, 

 as Dunman's "Glossary of Scientific Terms," London, 1878, 

 and published by D. Appleton and Co., New York, 1879. 



I find myself also in the same category, deserving the censure 

 of your correspondent, and agree with him entirely in the incor- 

 rect use of the word furculum for furcula, or still more properly 



