LINDSAY, ON THE PROTOPHYYA OF NEW ZEALAND. 109 
Hooker, for instance, mentions that various diatoms obtained 
by soundings on the Victoria barrier in the antarctic seas at 
a depth of 300 fathoms (1800 feet) are identical with fossil 
species occurring in Tripoli slate, and in the Phonolite stones 
of the Rhine. I have already explained that none of my 
Otago diatoms were marine. For collection of the latter I 
had no proper opportunity. Dr. Greville remarks, “ Your 
New Zealand list would have been considerably increased if 
you had collected marine species.’”* .... ‘ On the sea-shore, 
small tufts of seaweed mixed with zoophytes, &c., such as 
are often attached to shells, frequently contain good diatoms.” + 
He also recommends, as we have already seen, the explora- 
tion of the slimy surfaces of coast cliffs and caves. 
Soundings at sea are also frequently very fertile, even far 
from land, and at great depths ; the collects varying necessarily 
with the nature of the bottom. In this way, and from such a 
source, numbers of new and beautiful species have been brought 
to light by Dr. Roberts, of Sydney,t viz., species which inhabit 
the sea bottom of various parts of the great Pacific and 
Southern Oceans, as well as of parts of the Australian coasts. 
‘There is yet another fertile source of marine Diatomacee, 
viz., the stomachs of the various marine animals which feed 
on them directly or indirectly—their siliceous coats being in- 
destructible by the ordinary processes of digestion in the larger 
animals (including birds) which prey on the former: and in the 
guano and excreta of the birds in question. When I was pre- 
paring for a cireumnavigation excursion in 1861, Dr. Greville 
called my attention to this subject. ‘“ It is not unlikely that in 
the voyage you may have opportunities of collecting very in- 
teresting things. Salpe, &e., always contain diatoms (see 
Wallich’s Paper in ‘ Annals of Natural History,’ January, 
1860). If you press the small nucleus seen at one end of a 
Salpa, the contents escape, and there are the diatoms. Some 
Salpe are several inches long, and the nucleus large in pro- 
portion. No doubt many novelties remain to be discovered 
in materials collected from marine floating animals.’’§ 
Accordingly, solely with a view to the diatoms they might 
contain, I carefully collected at various points in the course of 
my circumnavigation—generally far from land (viz., in the 
middle of the North Atlantic, in the South Atlantic, in the 
logically speaking) being identical in some instances with existing species ” 
(Ebrenberg). 
* Letter, dated March 5th, 1866. 
+ Letter, dated June 11th, 1861. 
¢ And partly described in this Journal by Dr. Greville. 
§ Letter, dated June 11, 1861. 
