84 
Wallich, on Microscopic Objects. 
became difficult or impossible to seize upon some of tbese 
creatures. In the heaviest gales^ off the Cape, so long as the 
wind was ahead, some one or other of these would present 
itself in the net, and rarely were their stomachs barren. But 
the question, gentlemen, I presume, is not from what source 
may we derive material, but from what can we not do so, 
when even the lazy turtles we caught napping in a calm, 
mid sea in the Indian Ocean, needed only to have their backs 
scratched to afford the desired Diatomaceous contribution. 
The Salpse, however, were the most prolific, and generally 
the most abundant, and from their tiny stomachs it was easy 
to extract a number of novel and most interesting species, 
including Diatomacese, Polycystinse, and Foraminifera. When 
of the smallest, they could still be rendered available, for 
what was deficient in size was made up for in number, and my 
nets would frequently come up filled with their multitudinous 
bodies. In this case it was only necessary to crush or rather 
strain the mass through the material (crinoline by the way) 
of which the bag was composed, collect the heavier deposit, 
and treat it in the customary method. Sometimes the Salpse 
were from six to ten inches in length, with a digestive appa- 
ratus as large as a large marble, and from these a rich harvest 
was afforded. 
During the calms alluded to, I was enabled to observe that, 
extending for many degrees in the Bay of Bengal and Indian 
Ocean, the surface of the sea, to a considerable depth, abso- 
lutely swarmed with delicate yellow flocculent masses of the 
genus described by Mr. Brightwell, in the Society^s ' Transac- 
tions', under Ehrenberg's name of Rhizosolenia. Indeed, I 
believe I was the first to point out to Mr. Brightwell its fila- 
mentous character, and the appearance of its flocculent 
masses. Near the Equator this organism was accompanied 
by a Coscinodiscus, the cylinders of which were so large as to 
be easily distinguishable with the unaided eye from the upper 
stern ports, whensqever the sun poured down his rays into the 
clear blue abyss below. 
Nor was the Rhizosolenia confined to the eastern side of 
Africa. To the south of the Cape, and up the Atlantic as 
far as the Western Islands, it occurred frequently, but only in 
the Salpse stomachs — a fact that goes far to show that many 
minute forms escape observation solely from the tempestuous 
nature of certaiu seas ; whilst, although not more abundant, 
in the tranquil latitude of the tropics, or within land-locked 
seas, they rise towards the surface, and more readily exhibit 
themselves. 
There are certain mysterious influences, atmospheric pro- 
