and on the Alimentary Matter of the Salpse. 265 



nature of the materials to be found in deep soundings off the 

 coast of Australia, and in the neighbourhood of the South Sea 

 Islands, it is a discovery of peculiar interest to find the same 

 minute organic forms in vast numbers mixed up with the ali- 

 mentary matter of Salpians and other pelagic animals, obtained 

 in the open ocean far distant from those shores. 



The presence of the siliceous spicula and the fenestrated cells 

 of Thalassicolla with the embryonic shells of the pelagic Mollusca 

 might be readily accounted for; but how minute bivalves, Fora- 

 minifera, and a great variety of Diatomacese, and even Desmidiese, 

 including the genus Closterium — and all apparently recent — 

 could have been, as it were, casually inhaled, is not so easily 

 explained. Such are the facts, however; and the means by 

 which those bodies are so widely distributed seem inscrutable 

 to us, unless it be ultimately determined that they are in great 

 part purely pelagic examples of the orders and genera to which 

 they belong. This appears to be the most consistent view of 

 the matter, seeing that the agency of drift-weed, or any other 

 fortuitous cause, would be quite inadequate to produce so vast a 

 result, even so far as mechanical dispersion is concerned, not to 

 complicate the question with the more important part of the 

 problem, namely the preservation of the vitality and integrity of 

 the beings under consideration. 



Wherever the deep-sea lead plumbs the bottom, and, by 

 simple inference, in those depths immeasurably below its ex- 

 ploring reach, geometrical atoms exist, far removed from the 

 supposed source of their development. But when we know that 

 identical or allied forms, with their living crust or contents, are 

 being continually swallowed with the daily food of the Salpian 

 and the Pteropod, at the surface of the ocean, we can easily 

 perceive how, at the termination of their short existence, the 

 less perishable parts may ultimately be distributed through the 

 illimitable and unknown districts of the ocean-bed. 



The alimentary matter of the Salpa is composed of animal 

 and vegetable elements in nearly equal proportions ; and when 

 the microscope reveals the calcareous shells of Foraminifera, the 

 beautifully sculptured frustules of Diatomacese, keen siliceous 

 needles, and the sharp armature of minute Crustacea, within an 

 intestinal tube so tender and friable that it withers at the human 

 touch, — one cannot help admiring the operation of those con- 

 servative properties with which its delicate tissues are endowed. 

 Each atom yields to acute impressions as by an instinctive 

 intelligence, evading injurious contact ; and although a con- 

 tractility of the tube is essential to the due performance of its 

 functions, no evil thus befalls its integrity till the term of life 

 is at an end. 



