No. 469] BIOLOGY OF THE DUGONG 



61 



net are colored brown also. But if one is lucky he may capture 

 the animals during the full moon as well, and even with new nets 

 of shining whiteness. A further proof of the poorly developed 

 vision is the fact that the captive dugong did not notice very 

 much the waving of a white or a black flag and that not infre- 

 quently no notice was taken by the dugongs of the noiseless ap- 

 proach of the boat so that it was possible to observe these ani- 

 mals at very close quarters. Semon has remarked the same thing 

 and the fishermen employed by Dexler asserted that they had 

 repeatedly sailed right over feeding dugongs. This might be 

 flue, however, to the fact that it does not seem particularly shy 

 (Semon) or that it is but little concerned for its own safety 

 (Finsch). Feebleness of vision lias likewise been recorded in 

 case of the manatee (Chapman, '75, p. 454; Brown, 78, p. 295). 



Investigation of the eye in case of our captive dugong was very 

 difficult and therefore inadequate. For in order to do this one 

 must lie directly beside the animal on the sand, and as may be 

 readily seen, this is, to say the least, disconcerting when one does 

 not kiiow what movcMuent the creature mav make next. More- 



thc bulhi wrrc deep set and ((.iistantl v licl.i pointing slantwise 

 forward an<l downwar.l. and the slit between the eye lids was 

 narrow. Furthermon^ there flowed from the conjunctival sac 



was constantly obstructed as with a thick })hig. 



This had first to be vvuunv<\ an<l the .hort interxaK before it. 

 re-formation were utilized in a rapid study of ihv from porti.)n 

 of the eye. It was iini>ractical)lc to expose the l)n!l.u> 1a open- 

 ing the eye lid. with one\ finuci- f-.r th(>M' were < IommI ti^Iulv 

 at the slightest touch. If they were forcibly prr>M>.l apart the 



tracted in such a way that it disappeared inider the nienibrane 

 and the periorbital masses of fat that \\er«' loieed torwanl. Attrr 

 five or ten minutes there api)eare.l at the l.otioni <.f th.' fati) 

 funnel thus formed a bit of the eornea like a .mail bhuk .>pot 

 which became no clearer in spite of lonu waiting. When the 

 finger %vas removed the eye returned to its proper place, but for 

 hours after it remained more deeply in the socket than it had 



