1879.] MR. OTTLEY ON THE EYE-MUSCLES OF MAMMALS. 121 



Sternum oval, pointed behind, and similar in colour to the 

 cephalothorax. 



Legs pale dull yellowish, the femora being dark brown, and the 

 tibiae, metatarsi, and tarsi marked with brown, giving them a some- 

 what annulated appearance ; beneath the terminal claws is a small 

 claw-tuft. 



The palpi are short, and of a more uniform pale-yellowish colour, 

 clothed with, among others, some pale scale-like hairs above ; while 

 the digital joints have numerous longer, blackish ones beneath. 



Abdomen short-oval, and of dark maroon-brown colour, thinlv 

 clothed with short, pale grey, or whitish, rather shining, somewhat 

 squamose hairs ; an indistinct pale stripe runs obliquely from just 

 beneath each side of the fore extremity to, or towards, the spinners ; 

 the central longitudinal line is broadly blackish, but not very di- 

 stinctly defined ; and there are, on its hinder part, some very indi- 

 stinct paler, sharply angular lines in a longitudinal series ; on the 

 underside is a broad, longitudinal, central blackish baud, somewhat 

 narrowing to the spinners. 



Hab. Blumenau, Sta. Catherina, Brazil. On the leaves of various 

 herbaceous plants, in little three-entranced, white, silken nests. 



4. On the Attachment of the Eye-Muscles in Mammals. 

 —I. Qnadrumana. By W. Ottley, M.B., F.R.C.S., 

 Demonstrator of Anatomy at University ColIegCj 

 London. 



[Eeceived January 1, 1879.] 



During the last six months I have been enabled, by the kind 

 permission of Mr. Garrod, to examine the attachment of the eye- 

 muscles to the sclerotic in a large number of the Mammalia. In 

 some orders my observations have been as yet too few to enable me 

 to generalize from them ; but in the Quadrumana, where there has 

 been a larger amount of material at my disposal, the variations in 

 these muscles appear to be sufficiently well marked and characteristic 

 to deserve a short record. 



As a preliminary, I may state that, from the observations of Profs. 

 Donders, Helmholtz, and others, it has been established that in man 

 the six muscles are combined in the following manner : — 



In turning the eye up, the superior rectus and inferior oblique 

 act ; in turning it down, the inferior rectus and superior oblique j 

 directly inwards, the internal rectus ; directly outwards, the external 

 rectus. 



In any intermediate position three muscles are used, thus : — 



In turning the eye up and in, the superior and internal recti and 

 inferior oblique ; in turning it up and out, the superior and external 

 recti and the inferior oblique ; and so for the other movements. 



