Dr. J. E. Gray on new Genera of Lizards. 101 



he heard from the gentleman. The leg, when I saw it, looked fresh 

 where it had been cut oiF. 



(Signed) " Henry Stevenson." 



It will be remembered that Mr. Darwin, in his work on the 

 • Origin of Species,' speaks of the possibility of the seeds of plants 

 being occasionally transported to great distances by being enclosed 

 in earth adhering to the beaks and feet of birds ; and he mentions 

 the fact of his having "removed twenty-two grains of dry argillaceous 

 earth from one foot of a Partridge," in which earth " there was a 

 pebble quite as large as the seed of a vetch " (pp. 362, 363). Now 

 the mass of clay I exhibit is enormously greater than the quantity of 

 earth mentioned by Mr. Darwin, and is sufficient to hold the germs 

 of a very extensive flora. 



Apart from the statement of Mr. Stevenson, that the lump, when 

 he first saw it, was " as hard as stone," and the contrast thereby 

 afforded by the " fresh look " of the leg, a close examination of the 

 specimen convinces me that the clay, as that gentleman suggests, ac- 

 cumulated gradually. The two toes which are visible have become 

 distorted, and have accommodated themselves as well as they were 

 able to the shape of the mass. I imagine also that the loss of the 

 claw, noticed by Mr. Stevenson, has been experienced since the mass 

 attained nearly its present size and shape ; and it will be seen that 

 the stump has perfectly healed over. Now all this must have taken 

 some time ; I do not venture to say whether days, weeks, or months. 

 It is clear that, as the bulk and weight of the encumbrance increased, 

 it would more and more interfere with the bearer's means of obtain- 

 ing a livelihood ; and hence, weakened by starvation, the bird was 

 finally unable to rise, and met its death in the manner stated. 



If, as I believe, the clay accumulated by degrees, it is obvious that 

 there was once a time when the incipient mass was no heavier a bur- 

 then than the bird was able to bear in flight. What the actual limit 

 was, is a question we have no means of determining ; at least I am 

 not aware of any experiments having been made tending to show 

 what weight a Partridge is capable of supporting on the wing. But 

 I trust I have said enough to justify me in bringing this before the 

 Society as a singular illustration of the manner in which birds may 

 occasionally aid in the dispersion of seeds. 



Descriptions of Two New Genera of Lizards (Holaspis 



AND PORIODOGASTER, A. SmITH, MS.). Bv Dr. J. E. 



Gray, F.R.S., etc. 



Sir Andrew Smith, M.D., having most kindly sent to the collection 

 of the British Museum two most interesting Lizards, which he has 

 very properly named as the types of two new genera, I hasten to 

 send to the Society a short description of each of them under the 

 MS. names which Sir Andrew Smith has attached to them in his 

 museum. 



The first genus is allied to the family Lucertinidce, and is at once 

 known from all the genera of that group by the peculiarity of having 



