NOTES ON RETICULARIAN RHIZOPODA. 297 



amongst the Entoraostraca and other pelagic microzoa that 

 have been captured. 



At best the evidence afforded by comparative observations 

 is collateral rather than direct, and the only positive 

 testimony that could be adduced would be such as the sea- 

 bottom itself could alone furnish, and of a sort not easily 

 procured. Material brought up in large quantities by heavy 

 dredges and trawls is manifestly valueless for the purpose. 

 Under any circumstances living microzoa would not be 

 found except in the superficial film of the ocean-floor, and 

 even there they would be largely mixed with dead and 

 empty shells ; it would therefore be simple waste of time 

 to decalcify Glohigerina-ooze obtained in the ordinary way 

 with the idea of finding the protoplasmic bodies of the 

 constituent shells. Indeed, it would be almost as reasonable 

 to expect to find sarcode animals in a fossil deposit as in 

 material possibly representing a layer several inches in 

 thickness of the sea -bottom. The old methods of taking 

 soundings, either with the lead and tallow or with some of 

 the smaller appliances that succeeded it, though of com- 

 paratively little utility for the general purposes of zoological 

 investigation, were perhaps better adapted for securing a 

 knowledge of the superficial layer ; and it is even possible 

 that some of the discrepancies in the results obtained by 

 different observers may be explained through the different 

 methods by which their material has been collected. 



But, in addition to dredge and trawl, another appliance 

 was used from time to time by the "Challenger" naturalists 

 in bottom-collecting. This was a towing-net attached to the 

 trawl^ intended to receive the organisms thrown up by the 

 rough disturbance of the superficial layer of the bottom-mud. 

 It was without any great expectation of positive results that 

 I determined to experiment on some of the material obtained 

 by its means, inasmuch as shells more or less filled with 

 sarcode might not be those longest held in suspension, 

 though the difference in specific gravity between sarcode and 

 sea-water cannot be very great. But the result has been 

 satisfactory as far as it goes, and in one case the sarcode 

 bodies of six or eight per cent, of the shells operated upon 

 were left after treatment with acid. Amongst these were 

 easily recognised specimens of Glohigerina, Pulmnulina 

 Menardii and SphcBroidina dehiscetis. The sarcode was 

 yellowish-brown and granular, precisely resembling that of 

 in-sliore Rhizopoda that have been kept some time in alcohol 

 before being decalcified. The soft, jelly-like lobes of 

 Splioeroidina retained the form of the pseudopodial tubulation 



