586 MR. H, O. FORBES ON A SPIDER FROM SUMATRA. [DeC. 4, 



This milk-white patch is often met with in Monkeys, but on various 

 parts of the heart, sometimes on the auricles, at others on the ventricles ; 

 but it is always due to pressure either from an enlarged gland, defor- 

 mation of the thorax, pressure of an abscess, or some such cause. 

 But the most convincing case occurred in a young Rhea, which 

 was affected with rickets, so that the ribs yielded and allowed the 

 heart to be compressed between the broad sternum and the vertebral 

 column. In this case the anterior surfaces of the ventricles and the 

 right auricle were covered with a large milk-white patch due to the 

 pressure of the sternum. 



In conclusion I would remark that in merely recording the 

 diseases of wild animals in confinement little is to be gained, but in 

 elucidating the diseases of man Comparative Pathology will act as a 

 side light of no mean power. 



3. Oil the Habits of Thomisus decijjiens, a Spider from 

 Sumatra. By H. O. Forbes, F.Z.S. 



[Eeceived November 20, 1883.] 



(Plate LI.) 



Having sent the specimen now exhibited to Mr. O. P. Cambridge 

 for determination, he writes me : — " I believe it to be undescribed. 

 Mr. Blackwall has described a tolerably near ally from the E. Indies, 

 Thomisus tuberosus, Bl., and Karsch has described several which 

 appear to belong to the same group from other quarters ; but I do 

 not think yours is the same species as either, even if of the same 

 group, which, as Karsch gives no figures, is not certain. I have 

 close allies from E. Indies and Ceylon, and also from S. Africa, none 

 of which have as yet been described. The S. -African species is 

 almost exactly similar in its colouring and manner of sitting, so as 

 exactly to resemble the droppings of birds ; this was specially noted 

 to me by the friend who sent the specimens to me, and I have just 

 shortly noted it as an instance of protective resemblance in ' Spiders 

 of Dorset,' vol. i. p. xxix of Introduction. * * *. This group ought 

 to form a genus separate from Thomisus, but you might describe 

 yours provisionally as a Thomisus." I therefore propose to give this 

 interesting specimen the surname of Thomisus decipiens, in order to 

 identify it with the account of its habits which I am now about to 

 give. 



On June 25, 1881, in the forest near the village of Lampar, on 

 the banks of the Moesi river in Sumatra, while my " boys " were pro- 

 curing for me some botanical specimens from a high tree, I was rather 

 dreamily looking on the shrubs before me, when I became conscious 

 of my eyes resthig on a bird-excreta-marked leaf. How strange, I 

 thought, it is, that I have never got another specimen of that curious 

 Spider I found in Java which simulated a patch just like this ! I 



