18C8.] ON BIRDS FROM CONCHITAS. 137 



any admixture of earthy material. In the mature state I do not be- 

 lieve that there is any species that is destitute of keratode and com- 

 posed of sarcode only. I have never yet seen such a sponge ; but 

 in the young and earliest stages of the development of many species 

 we have them, as in Sponc/illa and others, simply existing as moving 

 masses of sarcode, which 1 believe have been designated by ob- 

 servers as Amceha. In every specimen that I have yet seen that has 

 been designated Halisarca I have always succeeded, by the aid of 

 Canada balsam, in detecting minute siliceous spicula in situ. As re- 

 gards the animal or vegetable nature of sponges, I may observe that 

 in our investigations of this subject we must take a broader view than 

 that of the ultimate structures of the animal. It is not a cell or a 

 cilium that will decide that question. Nature is not so widely vari- 

 ous in her general plan of operations as the world is prone to imagine. 

 The tree, with its almost unlimited capabilities of propagation by seeds, 

 by roots, or by cuttings, and in some cases even by single leaves, is 

 the fit type of the coral, with its innumerable polypes, in each of 

 which the germ of a separate animal is inherent. So it is with the 

 sponge; each morsel of it is the germ of a separate existence ; but the 

 combined compound existences within it is in reality the animal. It is 

 a congeries of existences in one. Not that the uniflagellate cells are 

 to be designated as the animal ; they are only vital points within, as 

 seeds, buds, or axillary bulbs in plants. The late eminent Surgeon 

 Liston on one occasion invited me to see the ciliated cells from a 

 polypus in the nose of a patient at University Hospital ; but no one 

 in such a case would dream of designating man as a congeries of 

 polyciliated cellular animalcula. Such bodies are more or less inci- 

 dental to the structure of almost all animals ; and in the sponges the 

 living organized mass is the animal, not its incidental parts, as some 

 authors would seem to imply. A knowledge of the structure aud 

 offices of such organs in its economy is an important point in the 

 history of the sponge ; but it is the combined structures and working 

 together of the whole organized mass that we must look to for the 

 determination of its character, either as an animal or a vegetable ; and 

 in the performance of its vital functions we have perhaps the most 

 positive and undeniable evidence of its truly animal nature. Its nutri- 

 tion is, like that of animals, voluntary and at intervals. It imbibes 

 its food through one set of orifices, digests that which it has received, 

 and excretes the rejected matter by appropriate oscula, while in 

 plants these vital operations are involuntary and continuous. 



6. List of Birds collected at Concliitas, Argentine Republic^ 

 by Mr. William H. Hudson. By P. L. Sclater, M.A., 

 Ph.D., F.R.S., and Osbert Salvin, F.Z.S. 



The authorities of the Smithsonian Institution, Washington, United 

 States, America, have most kindly sent over for our inspection a 

 series of birdskins collected at Conchitas, in the Argentine Re- 



