1872.] ON THE RED BLOOD-CORPUSCLES OF THE SALMONID.E. 833 



members of different communities makes it appear less strange that 

 they should assist each other : either the desire to see, as usual, 

 their buried-up neighbours becomes intense enough to impel them to 

 work their way to them ; or cries of distress from the prisoners reach 

 and incite them to attempt their deliverance. Many social species 

 are thus powerfully affected by cries of distress from one of their 

 fellows ; and some will attempt a rescue in the face of great danger 

 — the Weazel and the Peccary for example. 



Mild and sociable as the Vizcachas are towards each other, each 

 one is exceedingly jealous of any intrusion into his particular 

 burrow, and indeed always resents such a breach of discipline with 

 the utmost fury. Several individuals may reside in the compart- 

 ments of the same burrow ; but beyond themselves not even their 

 next-door neighbour is permitted to enter ; their hospitality ends 

 where it begins, at the entrance. It is difficult to compel a Vizcacha 

 to enter a burrow not his own ; even when hotly pursued by dogs 

 they often refuse to do so. When driven into one, the instant their 

 enemies retire a little space they rush out of it, as if they thought 

 the hiding-place but little less dangerous than the open plain. I 

 have frequently seen Vizcachas, chased into the wrong burrows, 

 summarily ejected by those inside ; and sometimes they make their 

 escape only after being well bitten for their offence. 



I have now given you the most interesting facts I have collected 

 concerning the Vizcacha : when others rewrite its history they 

 doubtless will, according to the opportunities of observation they 

 enjoy, be able to make some additions to it, but probably none of 

 great consequence. I have observed this species in Patagonia and 

 Buenos Ayres only ; and as I have found that its habits are con- 

 siderably modified by circumstances in the different localities where 

 I have met with it, I am sure that other variations will occur in the 

 more distant regions, where it is influenced by other extraneous 

 conditions. 



4. On the Size of the Red Corpuscles of the Blood of 

 the Salmonida and some other Vertebrates. By George 

 Gulliver, F.R.S. 



[Eeceived September 30, 1872.] 



Physiologists have now recognized the great importance in all the 

 vertebrate classes of the comparative magnitude of the red blood- 

 corpuscles, as noticed in my memoir on those of Moschus, Tragulus, 

 Orycteropus, &c. in the * Proceedings ' of this Society, February 1 0, 

 1870, wherein also are given some facts supplementary to those in 

 the same ' Proceedings,' February 25, 1862, and in my Lectures, 

 reported and illustrated by engravings in the * Medical Times and 

 Gazette,' 1862-63, concerning the value of the characters afforded 

 by these corpuscles in systematic zoology. 



The red blood-corpuscles of the Salmonidee are the largest that I 

 Proc. Zool. Soc— 1872, No. LIII. 



