May, 1902.] 



KNOWLEDGE. 



in 



death of the parasite withiu tho sac, the reniams became 

 calcified, .lud arnuud this nucleus the pearl was formed by 

 tlie secretiou of tlie epitlielimn liiiiufj the sae. The interest 

 i>{ this i>aper. to ornithologists, lay in the fact that the 

 adidt stage of the parasite v^as i)assed in the intestine of 

 the Eider Duck or the Common Scoter, both of which feed 

 largely on mussels. 



Loiigeoitii of the Eagle Oir/.— Mr. J. II. Gurney, in the Zoolor/isl 

 for March, records the death of one of his Eagle Owls on February 

 1st. It was Believed to be between thirty and forty roars of age. In 

 tlio fame communication he poinis out the fact that Mr. Meade 

 Waldo has iu his possession two birds of this species, one — a male — 

 which is seventy-one, and one— a female— which is fifty-sii years of 

 age, and the parent of ninety young ones. 



Earli/ Arrival of the Swalloii) and Sand-Martin—Ihe Field, 

 March 20th, records the arrival of the Swallow at Exeter on March 

 20tb, and of the Sand-Martin simultaneously at Batli and Exeter on 

 tlie same date (March 2titli) ; and remarks that this is at least a week 

 earlier than usual. 



All co)it)ibutions to the colwiin, either in the nay of notes 

 or photnijrai'hs, should be furuarded to W. P. Pycraft, at the 

 Xatitnil historii Museum, Cromuell Road, London, S.H'. 



Astronomical. — Dr. See has recently made an extensive 

 series of measurements of planets and satellites with the 

 aid of the great Washington refractor of 26 inches 

 aperture, giving special attention to the effects of 

 irradiation in increasing their apparent sizes. The 

 following are among the results obtained : — - 



screen consisting of a solution of picric acid and chloride 

 of copper iu water. — A. F. 



P)(>TANiOAL. — Torreija for February contains a paper bv 

 Mr. B, D. Halsted '' On the Behaviour of Mutilated Seed- 

 lings." The mutilation consisted of the removal of the 

 plumule. Seedlings of various plants were experimented 

 on, including some of the garden radish. On removing 

 the plumule soon after the plants were above the ground, 

 it was observed first that the cotyledons assumed a much 

 deeper green than usual ; then the petioles developed 

 extraordinarily, becoming three inches long, while the 

 cotyledons attained a bi-eadth of an inch and a half and 

 nearly double the thickness of those of a normal plant. 

 It was also observed that they were raised at an angle of 

 about 45° instead of being appro.\imately horizontal. A 

 microscopic examination showed that the greater thickness 

 of the cotyledons was due to the increased size of the 

 cells, and not to a multiplication of the layers. The roots 

 developed to nearly the ordinary market size. In seed- 

 lings of the common sunflower (Helianthus anniiiis), treated 

 in the same manner, a remarkable elongation of the hypo- 

 cotyl was noticed, this becoming twice as long as in the 

 unmutilated plants. 



Among the five plants figured in Ci(rlis's Botanical 

 Maqaxine for March is the first species of the numerous 

 Michaelmas Daisies introduced from North America into 

 European gardens. This is Aster Tradescanti. It is a 

 native of the eastern United States, and was first culti- 

 vated in this country by John Tradescant, gardener to 

 Charles I., iu the royal garden at Lambeth. Tradescant's 

 son travelled in Virginia, and to him is attributed its 

 introduction into Europe. Though this took place about 

 270 years ago, the present figure is the first to appear, 

 excepting a very rude cut in Morison's •' Historia." A. 

 Tradescanti has rather small white flower-heads, and is 

 far surpassed in beauty by many more recently introduced 

 species. Other plants figured in the Magazine are a 

 handsome new Passion Flower (Paggijfora amhiyua) from 

 Nicaragua, and a very fine Balsam {Impaliens grandijlora) 

 from Madagascar. The latter is remarkable for having 

 the largest flowers of all the numerous species of the 

 genus, so far as it is at present known. 



At the meeting of the Linnean Society on March 20th, 

 Dr. 0. Stapf exhibited some fruits of Melocanna hamhiis- 

 oides, a member of the grass family. It will be remem- 

 bered that the fruits of grasses are nearly always very 

 small, the largest commonly met with being those of the 

 wheat and maize. But in Melocanna the pear-shapjed 

 fruit attains a length of more than four inches. Melocanna, 

 moreover, deviates from the typical grasses in having 

 exalbuminous seeds, a peculiarity present in only three 

 species, so far as has been ascertained, in an order including 

 about 3500. Melocanna bainbusoides is a native of India, 

 from Assam to Tenasserim. — S. A. S. 



The effects of irrailiation were eliminated by making 

 observations about the time of sunset, and using a colour 



ZooiiOoicAL. — According to the preliminary abstract, a 

 paper of much interest and importance, dealing with the 

 evolution of horns and autlers, was read by Dr. Gadow, of 

 Cambridge, before the Zoological Society on March 13th. 

 The author is of opinion that the antlers of the deer, the 

 horn-like protuberances on the skull of the giraife, and 

 the true horns of the prongbuek and other hollow-horned 

 ruminants (Boouhe) are all different stages of evolution 

 from a single common type : the antlers of the deer being 

 the most primitive, and the horns of the Bovidx the most 

 specialised. From the fact that the bony horn-core of the 

 hollow-horned ruminants developis as a separate ossi- 

 fication, as do the horns of the giraffe, while the pedicles of 

 the antlers of the deer grow direct from the frontal bone. 



