692 REPORT— 1886. 



5. On some Abnormalities of ilie Frog's Vertehral Column.^ 

 By Professor Howes, F.L.S. 



Two case.s were described. In one a supernumerary (Xtli) vertebra was de- 

 veloped, wliicli had usurped the function of the true sacral one ; the latter had 

 established its custoruary connections on one side only, and the accessory processes 

 to be accounted for were shown to be the residtants of an attempt to make good 

 the loss by failure to do so on the other. In the second case the urostyle had 

 ' slipped ' and w^as displaced dorsally. Instead of becoming buried in the adjacent 

 soft tissues, or ankylosed to the neighbouring bony ones, it had entered into a new 

 connection with the sacrum — the body of which was prolonged upwardly into two 

 new articular facets. The process was held to be tantamount to that of reproduc- 

 tion of a lost part so familiar among invertebrates. 



MOyDA Y, SEPTEMBER 6. 



The following Papers were read : — 



1. On the Brain of an Aboriginal Australian. 

 By Professor Macalistek, F.B.S. 



2. On neredity in Cats with an Extra Number of Toes.^ 

 By E. B. PouLTON, M.A. 



Observations on this subject were brought before the notice of the British 

 Association in 1883, the complete account being published in ' Nature ' for 

 November 1 in that year (p. 20). The abnormality had been then traced through 

 six generations, and the stock in which it appeared through two earlier generations. 

 The observations have been continued from 1883 until the present time, resulting 

 in a large addition to the eighth generation, which now contains five families, and in 

 the appearance of one family in a ninth generation. A very high proportion of 

 abnormality continues in the recent families, and in the latest of all there are two 

 kittens with seven toes on the forepaws and six on the hind ; while in the last 

 family of the eighth generation one kitten possessed seven toes on each forefoot 

 and seven on one hind foot, with six on the other — the greatest abnormality which 

 has come under my observation, although an even larger amount (seven on botU 

 hind feet) is on record in the same stock. 



3. On the Artificial Prorhiction of a Gilded Appearance in certain Lepi- 

 dopterous Pupce. By E. B. Poulton, M.A. 



A few years ago Mr. T. W. Wood brought before the notice of the Entomo- 

 logical Society of London some proofs that certain pupte resemble the colour of the 

 surface upon which pupation takes place. This conclusion was received with some 

 incredulity by many leading entomologists, but without sufficient reason. For the 

 last few years I have been working upon the colour of larvfe in relation to the 

 colour of their surroundings, and I have shown that the colour may be modified 

 in one generation (in certain species) by an appropriate alteration of the surround- 

 ings. It seemed very probable from these experiments that the larvse were affected 

 by their surroundings through some sensory surface, and that by means of a nervous 

 circle a corresponding colour effect was wrought. It appeared to be very likely 

 that Mr. Wood's observations were but a special case of those general methods of 

 protection which I had been investigating. Mr. Wood explained his observations 

 by supposing that the moist surface of a freshly exposed pupa was photographically 



" Published in the Anatoviischer Anzrifirr, vol. i. Part XI. 1886. 

 ^ The complete account of all the families, with figures of the abnormal paws, is 

 published in Nature for the week ending Nov. 13, 1886. 



