338 



NATURE 



[November io, 1921 



graph of the Order of Oligochaeta, " 1895, p. 122 : — 

 "Genital setse associated with the male-pores only 

 occur in the Megascolicidae, the Eudrilidae, and (rarely) 

 in the Geoscolicidae, Lumbriculides ; in fact, they only 

 occur in those families of terrestrial Oligochaeta in 

 which the male-pores are provided with spermiducal 

 glands "; he notes (p. 688) that the clitellar setae of 

 the Lumbricidae are commonly modified in shape, being 

 very much longer and thinner than those on the non- 

 clitellar segments. Michaelsen, in the Tierreich 

 volume on Oligochaeta, 1900, p. 470, gives as a family 

 character of the Lumbricidae that commonly the setae 

 on certain segments of the anterior part of the body 

 are situated on papillae, and modified as genital setae 

 in the form of " Furchenborsten," with longitudinaJ 

 ridges and one or more intervening grooves at the 

 distal end. In Lumbricus terrestris (p. 512), "Usually 

 the ventral setae of segm. 26 or (less often) 25 and 26 

 are situated on broad papillae and modified as grooved 

 genital setae, slender, curved only at the proximal 

 end, 1-6 mm. long and 45/x thick." 



The above statements are not in all respects con- 

 cordant. The fullest of them, that of Borradaile, 



can apparently be traced 

 back, ^ through Vejdov- 

 sky's '"System und 

 Morphologic der Oligo- 

 chaeten," 1884, p. 156, to 

 Hering's paper in the 

 Zeitschrift filr wissen- 

 schaftliche Zoologie, .vol. 

 8, 1857, p. 418, who states 

 that peculiar setae are 

 found in Ltnnbricus agri- 

 cola (another synonvm of 

 L. terrestris) in the ven- 

 tral series in the tenth 

 segrnent, in the fifteenth 

 or one of the adjacent 

 segments, in the region of 

 segment 26, and, lastly, 

 in the clitellar segments 

 (3i-'?8); these peculiar 

 setae are thinner and 

 about double the usual 

 length. 



Some of the authors 

 quoted above do not mention any modification of the 

 setee near the male apertures ; of those who do men- 

 tion it some do not say in what the modification con- 

 sists, and those who describe it state that it is the 

 same as the modification in certain other segments, 

 e.g. those of the clitellum. 



I have examined three specimens of Lumbricus 

 terrestris, all with the clitellum and "ridges of 

 puberty" (on segments 33-36) fully developed; as 

 shown by the condition of the spermathecae, two had 

 copulated, one apparently not. For comparison, an 

 unmodified seta (a ventral seta of segment 17) was 

 taken ; this was of the well-known type, in length 

 074 mm., with the nodulus distal to the middle of 

 the shaft (portion distal to nodulus is to portion 

 proximal to nodulus as 2 is to 3). 



In segments 8-10 the ventral setae were much more 

 massive than usual, and about 124 mm. long, but 

 of the ordinary type (the larger size of the ventral 

 setae in the anterior segments can be appreciated on 

 examining the surface of the worm with a lens). Tn 

 segments 12-14 some setae were massive, like those 

 just described, while some were of about normal size 

 (082 mm. long) or slightly larger (0-91 mm. long). 



The ventral setse of segment 15 were not discovered 

 in one of the worms, perhaps because they had fallen 

 out ; in both worms which possessed them they were 



NO. 2715; VOL. I08I 



FiG.i.— (a) Clitellar seta of Z-ttwiftctts 

 terrestris (X30). (6) Ventral s,eta 

 of segment 15 (X64). (c) Tip of 

 ventral seta ot segment 15 (x 188). 



0-87-0-9I mm. long, with nodulus about the middle, 

 the shaft gradually 'tapering from nodulus to tip, and 

 only slightly curved (Fig. 1, b); the tip was excavated, 

 somewhat like a sugar-scoop (Fig. i, c). The lateral 

 setaa of this segment are of the usual size and type. 



The ventral setae of segments 25 and 26 were not 

 at all modified in type, though they were rather larger 

 than the one taken for comparison (0-96, 1-07, 

 117, and 1-2 mm. long). 



The setae of the clitellar segments correspond to the 

 descriptions of the authors quoted. They were 

 185 mm. long, slender, with no distinct nodulus, 

 though the shaft was thickest a little above the 

 proximal end; there was a marked proximal curve, 

 and the shaft was almost straight in the rest of its 

 extent ; it tapered very gradually and ended in a blunt 

 point, and was grooved or ridged along its sides in 

 the distal half (Fig. i, a). 



In the specimens examined, therefore, the only 

 modified setae (apart from variations in size) were 

 those of segment 15 and of the clitellum. The modi- 

 fication of the clitellar setae was that described by 

 certain of the authors above quoted ; but that of the 

 ventral setae of segment 15 was of an altogether 

 different type, which apparently has not hitherto been 

 recognised. J. Stephenson. 



Zoological Department, Edinburgh Univer- 

 sity, September 29. 



Speaking Films. 



In the article on speaking films which appeared in 

 Nature of October 27 Prof. Rankine says: "Com- 

 binations of picture films and ordinary gramophones 

 have been frequently tried without success sufficient 

 to ensure their survival in practice. The difficulty, 

 of course, mainly arises from the impossibility of pre- 

 serving svnchronism between a gramophone record 

 and film." 



This mechanical difficulty could be overcome, at 

 least in the early stages of the life of a film, but 

 even then a more serious difficulty, which may best 

 be described as psychological, would remain. It must 

 be remembered that both by the film pictures, the 

 film sounds, or the gramophone sounds deceptions 

 are practised on the human senses. The eye is 

 deceived into believing that it sees real people in 

 movement when it is doing no more than witnessing 

 the antics of graduated shadows. • If the film fails 

 to deceive the sense of seeing, it fails also in its 

 psychological effect. The intimacy with which 

 devotees of the "pictures " speak of the "film stars " 

 who are "featured" shows that they do indeed be- 

 lieve that they see them, that it is actually Charlie 

 Chaplin or Mary Pickford who is present before them. 

 It is only when the senses surrender themselves com- 

 pletely to this deception that the emotions are fully 

 affected. 



In the same way the gramophone deceives the sense 

 of hearing. Unless we can actuallv believe that we 

 hear Caruso or Sir Harry Lauder the enjoyment and 

 the effect will remain partial. 



Now, mv own experience is that vou may deceive 

 one sense at n time, but not two. You may deceive 

 the eve with the film or the ear -with the gramophone, 

 but if you attempt to deceive both together failure 

 results and both deceptions are destroyed. Some 

 vears ago I witnessed a film which showed a nigger 

 dancing to a banjo. As long as he only danced I 

 forf^ot that he was a black-and-white picture on a 

 white sheet, but when a gramophone attempted to 

 render the words of his song and the banjo accom- 

 paniment the illusion disappeared. . There was no ap- 

 pearance whatever of a nigger singing. What I 



