September 29, 1910] 



NATURE 



397 



yellow straw-colour, as in the nyala and situtunga. They 

 have also a more distinct back ridge than in other kudu 

 horns, and thereby again approximate to those of the 

 two last-named species ; while the bony cores have no ridge 

 corresponding to that on the sheaths. The skull has a 

 transverse diameter of 43 inches across the orbits, and a 

 contour length of 15I inches, the corresponding dimensions 

 in a skull of the typical species with horns of the same 

 length being 51 inches and 14J inches. 



The spotted kudu, as 1 have called the new species, 

 is in great degree intermediate betw'een other kudus and 

 the situtunga and nyala. It agrees appro.ximately in size 

 with the typical kudu, but in horn-characters is to a 

 certain extent intermediate between that species and the 

 situtunga or nyala. In the presence of a white patch on 

 the throat and a second on the chest it resembles the 

 lessrr kudu and situtunga, as it also does in the absence 

 of a neck frill ; but in its long, coarse, dark, and white- 

 spotted coat it comes much nearer male situtungas and 

 nyalas than to either of the striped kudus. The ears are 

 rather narrower and more pointed than in the typical 

 kudu. 



I propose to name the species Strepsiceros 

 reserving for 'future consideration the question wheth 

 this species does not render it advisable to merge the 

 genus Strepsiceros in Tragelaphus. If that course were 

 adopted, the typical kudu would become Tragelaphus 

 strepsiceros, the lesser kudu T. imberbis, and the spotted 

 kudu T. buxtoni. R. Lvdekkek. 



The Habits of Worms. 



So little is known about the habits of worms that it 

 seems desirable to place on record any new observa- 

 tion calculated to throw light on the subject. On Sep- 

 tember 17 I received from Mr. Edwards, curator of the 

 Worcester Museum, a small tube containing about half 

 a score of living worms. The letter which accompanied 

 the tube informed me that the worms were found in a 

 lavatory basin. It was assumed that they had found 

 their way up through the waste-pipe, as none had been 

 found w-lien the plug was fixed in the bottom of the basin. 

 The worms were taken in the morning when the plug 

 ■was not inserted, and when the water had been very 

 slowly dripping all night. They were found singly, but 

 when placed in a tube coiled themselves into a ball, and 

 were difficult to separate. Each worm was about three- 

 quarters of an inch in length, possessed of red blood, and 

 having five to eight seta; in each bundle. These features, 

 together with the shape of the brain and spermatheciv, 

 show the species to be Pachydrilus subterraneiis, 

 Vejdovsky. It was first described in 1889, and on .April 

 8, 1892, I received it from the late Dr. Plowright, of 

 King's Lynn. This was the first British record ; but it 

 has since been found by Mr. Southern and myself in 

 various parts of the British Isles. It was obtained by 

 Prof. Vejdovsky from the underground waters of Lille 

 and Prague, and has more than once been sent to me 

 by irate persons who complained that it had been found 

 in their drinking water. 



Pachydrilus (Lumbricillus) belongs to the large and 

 important order of enchytrjeids, some of the species of 

 which are parasitic upon plants, while others feed on 

 decaying leaves and vegetable matter, and yet others live 

 in the water. As I am preparing a monograph of 

 British annelids for the Ray Society, I am exceedingly 

 anxious to obtain information and materials for making 

 the work complete, and shall be grateful if observers will 

 submit specimens of annelids of all kinds for identifica- 

 tion, together with observations of their habits. 



HiLDERic Friend. 



Swadlincote, Burton-on-Trent. 



Erasmus Darwin on Flying Machines. 

 Prof. Meldol.a's reference to Erasmus Darwin's pro- 

 phecy of flying machines (p. 370) omits the most remark- 

 able proof, as it seems to me, of his insight into the 

 future. The verses w'hich he quotes are from Canto I., 

 lines 289-96, of the "Botanic Garden"; on line 254 



NO. 2135, VOL. 84] 



there is a note in which occurs the following passage (the 

 italics are mine) ; — 



" .As the specific levity of air is too great for the sup- 

 port of great burthens by balloons, there seems no prob- 

 able method of flying conveniently but by the power of 

 steam, or some other explosive material, which another 

 half-century may probably discover." 



University College, London. Arthur Platt. 



CAUSAL GEOLOGY ^ 



IN science there can be no orthodoxy, and conse- 

 quently there are no heresies. Prof. Schwarz's 

 book will be read and circulated, instead of being 

 burnt as a danger to established modes of thought. 

 It will bring, in consequence, a freshness to those who 

 have repeated, year after year, the same explanations 

 of phenomena in their courses of instruction. They 

 will feel much like the humdrum banker, who thinks 

 that he really understands his business, until his son 

 biixtoni, . ..^akes him one evening to the theatre, and he meets 

 for the first time with the ide;d villains of finance. 

 The planetesimal hypothesis of Chamberlin is held by 

 the present author to enable "one tu build up a system 

 of geology without an appeal tu the unknown and 

 the unknowable " (p. v). " Unknowable " is a rash 

 word ; but there is a good deal more of the unknown 

 than of the known in the explanations of earth- 

 structure put forward by Prof. Schwarz. We remem- 

 ber a paper of his, in Which the former boundaries 

 of continents and oceans were ingeniously dediiced 

 from a rock-fragment discovered in a southern isle. 

 The present work includes speculations of a similar 

 order of magnitude, but the underlying facts are mar- 

 shalled more strategically, and far bigger battalions 

 are brought into the field. 



The planetesimal hypothesis, as developed by Prof. 

 Schwarz, leads him to the conception of a cold earth, 

 steadilv growing in bulk by the accretion of meteoritic, 

 or, as he prefers to write it, meteoric matter. The 

 phenomena of the surface cannot, then, be caused by 

 shrinkage of the interior, nor can volcanic action be 

 ascribed to general internal heat. Earth-movements 

 (p. iSq) are said to develop sufficient heat to vaporise 

 water in the crustal layers affected by them ; all this 

 water has crept down by capillary action from the sur- 

 face, and may form outbursts of steam, shattering the 

 sedimentary rocks around the orifice. If the heat 

 generated is sufilicient to melt the sediments, the pro- 

 duct, with the water in it, appears as an ordinary 

 upwelling of lava. 



From the author's point of view, all gneisses and 

 granites are derived from sediments by metamorphism 

 in dissolving waters, or bv actual melting (pp. 40, 

 221, &c.). The ultrabasic vents of Kimberley and Pre- 

 toria, so well known as the diamond-pipes, contain 

 "meteoric matter of the centrosphere " (p. 198), since 

 here faultiner was sufficiently profound to melt up the 

 ferriferous masses that underlie the ordinary crust. The 

 faulting is accounted for by the transference of sedi- 

 mentary matter from one part of the surface to 

 another, the overladen rocks flowing away under the 

 pressure ; and we are given to understand that melt- 

 ing, with production of granite domes, or of lava 

 ready to arise in fissures, takes place where water_ is 

 present, and where the pressure is most intense, in- 

 stead of where pressure is relieved. A fine instance 

 of revivalism in geology appears on p. 227, where 

 Prof. Schwarz, rejecting Darwin's observations in 

 South .Africa, and lit 'par lit injection generally, 

 urges that "thin laminae of granite substance bedded 

 in between metamorphosed sediments " may result 



1 "Causal Geology." By Prof. E. H. L. Schwarz. Pp. viii+248. 

 (London : Blackie and Son, Ltd., igio.) Price js. 6rf. net. 



