98 



KNOW^LEDGE 



[JuiY 7, 1882. 



rfstraint from the hip. Ami though in tho shop it may seem that 

 « •• scat " ia much easier whcu used as one might use au onlinnry 

 chair, and sat " siiuub " U|>oii, when ritling this cannot bo done, 

 and at tho same time permit the legs to move from tho hips (ag in 

 «Talking>, which is a sine <]iiti noii for comfort in riding. A man on 

 a seat must have his legs bent at an acwto angle at the knocs, and 

 he then presents a Tery unsightly appearance, with his kucos iioji- 

 ping up and down almost up to his chin, besides the extra fatigue 

 invoh-cd. Saddles arc made with a broad seat, and also with backs, 

 and they are really most comfortable, and tho pommel so divides 

 the fork as to avoid all dialing. Ex-Bicyclist. 



[460] — It may interest those of your readers who arc trioyclists to 

 loam that Mr. Marriott, of Nottingham, has ridden from Derby to 

 Uolyhcad, through Burton, Lichfield, Shifnal, Shrewsbury, Corwon, 

 Bettw8-y-Coed, and Bangor, a distance of one hundred and eighty 

 miles, in iwenty-threo hours and three cjnarters on a tricycle. Tho 

 road for quite half the distance was mountainous, .some of tho hills 

 being six and scren miles long, and in many parts tho roads were 

 so rough that it was like riding through the bed of a stream dried 

 up. For a tricyclist. this is the longest journey in twenty-four 

 hoars on record. Jon.v Bh6w.ni.so, L.T.C. 



INFLUENCE OF CLIMATE ON PLANTS. 



[461] — In a number of Kxowledoe on which I cannot at present 

 lay my hand, I noticed some facts with regard to the influence of 

 climate on plant.". It way interest your readers to know that plants 

 foci severely the change in their usual habits which takes place 

 when they are transplanted from Europe to South Africa. Tho 

 Curator of tho Botanical Gardens here, who has, perhaps, more 

 practical knowledge of tree-planting than any man in tho country, 

 informs me that this is markedly the case with regard to fruit- 

 trees. The reversal of the season.'), occasioned by tho change of 

 l:emispherc, bewilders tho plants, which are in some sense " edu- 

 cated " to such a degree that they arc not able to survive the shock. 

 Tho only chance of getting them to grow is by grafting, when they 

 borrow tho constitution of tho tree on which they are grafted, and 

 acclimatise readily. Ordinary deciduous trees bohavo very ii-rc- 

 gularly also. Sumctimes they will pull through, sometimos they 

 die, but the first i uttings never appear to thrive. I understand that 

 evergreens are not affected. 



Birds take to tho change of season well, if one may judge by 

 the few European sparrows which have beeri introduced. European 

 dogs generally die. Imported oxen and horses appear to do well, 

 provided they receive tho same amount of care which they expe- 

 rience at home. Cats thrive. 



Perhaps I may bo pardoned if I suggest that tho appearance of 

 nnmerous articles from upholders of Darwinism in your capital 

 magazine, must not lead your less scientific readers to imply that 

 Darwinism is by any means universally accepted. It is, admittedly, 

 only a hypothesis. 1 use tho word hypothesis in tho sense to which 

 yon restrict it in " Pleasant Ways in Science " (p. 315), as an opinion 

 not based on phenomena. Dr. Mivart, one of tho greatest of living 

 anatomists, terms it, with all due solemnity, " a jmerilo hypothesis." 

 May I be allowed to recommend to those of your readers, who are not 

 terrified by mero weiglit of names on the other side to road care- 

 fully Mivart on the ' Genesis of Spcnies," Dr. Elam's " Winds of 

 Doctrine," and Dr. Beale's " Protoplasm," in which they will find 

 refreshing antidotes to the works of Danvin, Iluxley, and Uacckel, 

 the positive, comparative, and superlative exponents respectively of 

 the faiihionablo doctrines in trancendental doctrine. Especially let 

 them study well the history of " Batbybius Uaockelii," two unfit 

 evolutions from tho original Darwinic idea, which have ceased to 

 survive. 



As a last suggestion (1 hope yon will forgive the space) moy I 

 remark that your magazine is extensively read this side the 

 equator, and that some good map.i of tho southern sky would bo 

 appreciated both here and in Australasia. j! Nixox. 



Omhamstown, Cape Colony, ilmj i, J882. 



THE SPAWN OF " DOIUS TUBEHCULATA" (COV.). 



[462] — I have lately obtained a largo mass of the riband spawn 



of tho largo Nudiliriinoliiato Mollusc, Dnria tubeyeulata, which, I 



think, worth mentioning in your columns. While on a visit last 



week with a relative at West Kirby, near Iloylake, Cheshire, I 



availed myself of the oji|)ortunity which a tide of about 18 ft. 



fTordcd, of a visit to the Uilbrc inland, at tho month of tho Dec. 



■I;ivingon a previous occasirm been fortunate enough to secure 



vemi fine sfiecimcns of tho beautiful Dcndronotiiit arliorc/ccnii, 1 



' ioaght I would trj- my luck again. I may mention that Ililbro 



i-ilaotl during tho tides of the spring and aotamn equinoxes is well 



worth visiting for specimens of marine zoology. Tho tides of last 

 week, however, were not sutficiontly low to expose at their full ebb 

 tho most promising places. At one spot 1 CBi>iod a largo white 

 mass of something hanging from a rock, and this I found to bo tho 

 riband spawn of Doris tiihciculata ; it was hanging from tho undcr- 

 lodge of a rock of red sandstone, to which it was firmly fixed, 

 except nt one end of the mass, where, for about three or 

 four inches, it hung loosely from tho rest. On detaching tho 

 mass and unfolding it, I was astonished at its great length. 

 1 did not measure it, but 1 am sure lliat it was more than a mile 

 long, and being in one uniform, uninterruptod band, it must have 

 been tho product of a single parent. Tho breadth of tho band I 

 afterwards found to measure one inch and four-tenths. Not far 

 from this spot, a Iloylake fisherman, who was after prawns, scooped 

 out in his net from under the ledges of the rock two creatures, 

 which ho politely gave to me ; these were two fine specimens of the 

 Nudibranch itself. The largest, which was of a beautiful lemon 

 colour, without a single spot of any other colour, measures — for I 

 have both specimens alive now — four inches in length and two-and- 

 a-half in breadth. Tho other is not so largo, and is handsomely 

 marbled with yellow, dark brown, and delicate pink. I do not 

 know whether this spawn-mass is of unusual size, but Alder and 

 Hancock speak of an unfolded coil of Doris spawn of nine inches in 

 Irnf^'tli and nearly ono inch broad as being ono of lai-go size. 

 .Spieiniens of Vuris tuherculula have been found measuring five 

 inches in length ; I should tliink that tho parent of the mass 

 I found must liavo been larger; for the riband must have 

 been fully forty inches long. This band, which is transparent, 

 and fairly tough, is full of countless numbers of ova or embtyos. 

 I have kept a portion of this spawn in salt water nearly a week; 

 on examining it under the microscope today, I find many of tho 

 embryos still alive and considerably developed. Very curious it is 

 to witness the constant activity of these baby-nudibranohs, as they 

 perform their rapid rotations within tho enclosing transparent mem- 

 branes. Jn some of these only ono embryo is scon, in many, two 

 are found ; and not unfrcquently, throo are seen to disport them- 

 selves in one membrane or chorion. Conspicuous aro tho two oval 

 lobes, which are thickly fringed with long, strong cilia, by means of 

 which the little creature rows itself rapidly within its circumscribed 

 " oval," and which aro destined to play the same locomotive func- 

 tion when it is liberated from its chorion. Now these cilia are in 

 motion, now they stop their machinery, and tho littlo croaturo 

 partially withdraws itself into an exceedingly thin, transparent 

 shell, somewhat resembling that of tho nautilus. Tho pedal process 

 (foot) is apparent, and careful focussing reveals the presence of a 

 delicate, transjiarent operculum on the under side of the foot. I 

 see clearly the two circular otoliths in the region of the mouth; 

 the stomach intestine and other viscera are evident enough, 

 in a mass, bat not easy to distinguish separately, owing to its 

 opacity. Tho muscle which attaches the embi-yo to tho bottom of 

 the shell is scon in tho shape of a senii-trnnsparont conical organ. 

 Nearly tho whole of tho rest of the body of tho embryo is separated 

 from the shell by a well-defined clear space. Tho figures in Alder 

 and Hancock's Monograph (Fam. I. pi. 3) are well shown, and what 

 is before nio convinces mo of their accuracy. Of the thousands of 

 thousands of ova contained in the spawn of tho nudibranchs, how 

 few aro destined to survive and reward the marine zoologists by 

 their presence as adult animals. I am reminiled ut what occurs in 

 oysters. Delicate locomotive larv;e, when free swimmers, aro 

 at tho mercy of tho rough waves, and in the troubled 

 sea of their infancy they have but littlo chance of settling 

 down to a quiet life, and developing the characters which 

 murk tho respective adult species; so that, I should suppose, tho 

 nudibranch babies require similar conditions to those necessary for 

 the development of the young collated oysters, vie., a calm soa and 

 a warm temperature, i secured one raoro nudibranch during ray 

 short visit at Ililbro, a fine JMis papillosa. But, beautiful in 

 colour and curious often in form as our nudibranchs are, it must be 

 confessed that they are, as adults, dreadfully sluggish in their 

 movements -painfully slow. This, 1 think, is especially true of 

 Dori.1 tnherruliita. " Do move on, sir," ono repeals in vain. I call 

 them " Cretans." Would you know why ? Because they are 

 " slow bellies." Even as Epimenides calls the people of that island, 

 in a lino quoted by St. Paul (Titus i., 12) : — 



Kp»}r«c «»< yl/ivarai, koki'i Sijpin, yaaripii; Apyai. 

 Of course it is only tho latter description that is applicable to 

 nudibranchs. W. UouurnoN. 



Hay 22, 1882. 



Coal Dndkb IvONDon. — .\t tho half-yearly mooting of tho pro- 

 prietors of the Sonthwark and Vauxhall Water CJompany, it was 

 mentioned incidentally that in sinking a now well at Streatham, 

 pieces of coal had been founri LjO feet below the surface. — Daily 

 Neivi. 



