U\ XKWI.V-HUHX CAJKO Sl'lNV MICK. 



Mv. R. I. PocoCK ulso exhibited a female hybrid, bred in the 

 Society's Gardens, between a male Black Lemur {Leimor macaco) 

 and a female of the Red- fronted variety of the Fulvous Lemur 

 (Lemur fidvus rujifrons), and pointed out that the offspring re- 

 sembled neither of its parents. It had not inherited the facial 

 fringe of its father nor the white over the eyes and on the fore- 

 head of its mother, this ai-en. of the head being dark ashy black 

 witli a deeper tinted central line, more approaching the colour 

 seen in the Black-fronted variety of the Fulvous Lemur (Z. fidvus 

 nigrifroiis). 



The Hon. N. Cpiarles Rothschild, M.A., F.Z.S., exhibited the 

 following species of Fleas, which were of interest in connection 

 with the spreading of plague by these insects : — Pidex irritans, 

 Xenopsylla cheo^iis, Ctenocejihalics canis, 0. fells, Cerato2)hyllus 

 fasciatus, C. londimensis, Ctenopsylla mai/ardi. 



Mr. J. Lewis Boxhote, M.A., F.L.S., F.Z.S., exhibited in 

 spirit a young Caii'O iSpiny Mouse {Acomys cahirinus) about 12 

 hours old, and pointed out the advanced state of the young a,t 

 birth as compared with the common House-Mouse and other 

 species of the genus Jlas. 



In Acomys the 3'oung at birth Avei'e of a pale slate-colour and 

 sparsely covered on the upper parts with downy hairs 2 to 3 nnu. 

 in length. Across the lower j^art of the back the spines could 

 be distinctly felt. 



In spite of this advanced development the period of gestation 

 was only 1 1 days at the most. In the case under notice the male 

 was introduced at 7 p.m. on 19th July and the young were born 

 between midnight and 9 a.m. on the 31st July, a maximum 

 period of 11 days and 14 hours. The period in the House-Mouse 

 was about 13 days. In Acomys the usual number in a litter was 

 three ; four were exceptional, but two were not uncommon. 



In correlation wdth their forward development the j^oung were 

 also very large at birth, as a comparison of measurements of the 

 individual exhibited and the average measurements of an adult 

 male show : — • 



Young 

 12 hours old. Ad. (? . 



Head and body ... 51 mm. 101 mm. about | full size. 



Tail 35 mm. 105 mm. ,, g ,, ,, 



Hind foot 14 mm. 18 mm. ,, | ,, ,, 



Ear 8 mm. 17 mm. ,, g ,, ,, 



When 8 to 10 days old the young were able to take care 

 of themselves, and on the fourth day after birth their eyes were 

 open and they occasionally left the uest and ran about the cage. 



They bred at a very early age, and by the agency of a young male 

 born on the 4th ,Tune progeny were produced on the 31st July, 

 so that it must have bred Avhen only 46 days old. 



