September 19, 1907] 



NA TURE 



533 



the gill clefts. In the skate the spiracles play a more 

 important part, for when the animal is at rest all the 

 water which enters the pharynx does so by way of the 

 spiracles; none enters by the mouth. In Rliitia squatina 

 (the angel-fish) no movement of the spiracles is visible ; 

 there is a uniform current of water into the mouth and 

 spiracles, and the water is driven out again through the 

 gill slits by the undulations of the " gill covers." 



The Systematic Position of Polyplcrtis. 

 Mr. E. S. Goodrich pointed out that Polypterus and 

 Calamoichthys, both from the rivers of tropical Africa, 

 forming the order Polypterini, have no near relations 

 among living fish. The presence of rhomboid ganoid 

 scales, paired gular plates, a persistent spiracular gill cleft, 

 true clavicles, a bilobed air-bladder, and a straight tail, 

 form a combination unknown it\ any other order. Owing 

 to their lobate pectoral fins, paired gulars, rhomboidal 

 scales, outwardly diphycercal tail, and to a considerable 

 resemblance in the disposition of the roofing cranial bones, 

 Huxley (1861) placed the order Polypterini in the group 

 Crossopterygii, in which it has been left by subsequent 

 writers, associated with such extinct forms as Osteolepis 

 and Holoptychius ; but on comparing Polypterus with these 

 fossils the resemblance is by no means close. The 

 similarity in arrangement of the surface bones of the skull 

 is only general, and such as may be found in most 

 primitive Tcleostomes. The scales of Polypterus and 

 Osteolepis are of very different structure, those: of the 

 former being of the true ganoid type. The tail is not 

 truly diphycercal, but of a modified heterocercal type, the 

 notochord, in the young at any rate, being turned up- 

 wards (as show-n by Budgett). In Actinopterygii there 

 may occur a median ventral gular plate as well as two 

 lateral series; two of the anterior plates of the lateral 

 series may be more or less enlarged, as in Palreoniscid.ne : 

 the paired plates of Polypterus may be the homologues of 

 these plates of the .Actinopterygii. and not of the more 

 median plates of the Crossopterygii. The skeleton of the 

 pelvic fin and girdle of Polvpterus is much more actino- 

 ptervgian than crossopterygian in structure. The re- 

 semblance of the fins of Polypterus to the lobate fins of 

 the Crossoptervgii was shown by Budgett to be superficial 

 only. The relationship of Polypterus to the .Actinopterygii 

 is supported bv a comparison of the structure of the scales 

 and of the fins, by the presence of large solid otoliths in 

 the ear, and the double nostrils on each side of the snout, 

 while the brain, the alimentary canal with its pyloric 

 ca?cum, the kidnevs and testes, the separate anus and 

 urinogenital apertures, are also consistent with this view. 



Colour Variations in the Skin of the Hamster. 

 Prof. Simroth (Leipzig) exhibited a series of skins of the 

 hamster (Cricetus frumentarius), which is common in the 

 cornfields of some parts of Germany, and especially in 

 Thuringia. The usual coloration of the skin is grey along 

 the back and black ventrally, these two being separated 

 by a lateral reddish area, and there are three white or 

 pale yellow patches at the sides of the head and breast. 

 The skins, however, show great variations in coloration. 

 In one series the red areas and then the white patches 

 disappear, the upper side becomes grev, greyish-brown, 

 and finally black, so that the whole skin is now black. 

 In another series the under side becomes lighter, followed 

 by a similar change on the upper side, leading finally to 

 an albino, the rarest variation. The black specimens were 

 first noticed during the hot summers some years ago. 

 It is not yet clear whether these colour variations are to 

 be attributed to climatic conditions or are atavistic. 



Photographs of a Young Living Okapi. 

 Sir E. Ray Lankester, K.C.B., F.R.S., exhibited photo- 

 graphs of a living okapi taken by Signor Ribotti at 

 Bambili, on the Welle Ri%-er, in the Congo Free State. 

 The animal is a young colt showing the striping of the 

 upper part of the fore and hind legs and hind quarters, 

 and the dark body colour, apparently as in the adult. It 

 is worthy of note that this is the first time that a European 

 has seen a living specimen of the okapi. Some doubt 

 having been recentlv expressed as to whether okapi is the 

 native name of the animal, Sir E. Rav Lankester remarked 



that he had shown the photographs and a portion of a 

 skin to some of the .African- pygmies, now in London, who 

 recognised them, and at once spoke of them under the 

 name okapi. 



Plankton Ini'cstigations off the Isle of Man. 

 Prof. Herdman gave an account of his plankton investi- 

 gations off Port Erin during April. These were under- 

 taken with the object of testing different kinds of open 

 and closing tow-nets, and of gaining information regard- 

 ing the detailed distribution of the organisms according 

 to locality, depth, and date. E.xamples were given of 

 very different results, quantitative and qualitative, obtained 

 from quite similar nets hauled not far apart as regards 

 both distance and time. Sudden variations in the vertical 

 and horizontal distribution of the plankton were discussed, 

 and the seasonal changes were also considered ; obviously 

 great care and much observation of the gatherings of 

 organisms are required before these can be considered as 

 adequate samples. Prof. Herdman concluded that our 

 methods must be investigated before the attempt to in- 

 vestigate nature on a large scale can be made, and also 

 that an intensive study of small, well-chosen areas is 

 necessary before conclusions can be drawn with regard 

 to relatively large regions such as the North Sea or the 

 .Atlantic Ocean. 



.Mr. W. E. Collinge traced the rise, and pleaded for 

 the due recognition, of economic biology ; Prof. Simroth 

 gave an account of his pendulation theory in relation to 

 geographical distribution ; Mr. J. W. Jenkinson described 

 his further experiments on the development of the frog ; 

 Mr. T. V. Hodgson pointed out the principal features of 

 interest in the collections of Pycnogonids from several 

 .Antarctic expeditions ; and Prof. R. J. .■Anderson detailed 

 his observations on the thickness of the skull _ in 

 Mammalia ; but these papers cannot be well summarised 

 i-n the space here available. J. H. Ash worth. 



PHYSIOLOGY AT THE BRITISH 

 ASSOCIATION. 



THE phvsiological section has for several years devoted 

 one morning to seme subject of general interest. 

 This policy was inaugurated at Cape Town by the dis- 

 cussion on the effect of climate upon health; it was 

 followed up at A'ork by one on the physiological mini- 

 mum of rest for children, opened by Dr. T. D. 

 Acland ; and this year at Leicester by one on the 

 physiological and therapeutical value of alcohol. The 

 interest which this subject has aroused of late made it 

 a particularly appropriate one, more especially as the 

 matter has not been recently discussed in at all a dis- 

 passionate way. From this point of view the meeting 

 at Leicester was all that could be desired, and perhaps the 

 most remarkable feature in connection with it was the 

 very narrow margin which separated those who took 

 different views as to the value of alcohol. 



The discussion was opened by Prof. Cushny, F.R.S.. 

 who reviewed the effect of alcohol on the various systems 

 of the bodv. alluding especially to its very doubtful effect 

 as a stimulant to the alimentary system, its effects upon 

 the circulation, especially the heart, as recently worked 

 out by Prof. Dixon, arid its action upon the muscular 

 nervous svstem and on the power of the body to resist 

 toxic agents. In doing so he introduced some of the 

 subsequent speakers. Dr. Rivers gave an extremely 

 interesting account of the use of the ergograph in obtain- 

 ing records of the effect of alcohol. It was very remark- 

 able to see how great was the psychical element in ergo- 

 graph tracings ; this, indeed, was so marked that much 

 the same effect could be obtained by giving a dose of 

 alcohol and one which the patient thought was alcohol, 

 or even one which merely excited his curiosity. Dr. 

 Rivers has been able, in conjunction with Prof. Di.'ion, 

 to administer considerable doses of alcohol in forms which 

 were not .recognisable, and in doing so he has found no 

 certain beneficial effect on the power of performing 

 muscular work. .Some curves shown by Dr. Waller, 

 F.R.S.. were quite in harmony with this view. These 



NO. 1977, A'OL. 76] 



