548 JOTTINGS FROM THE BIOLOGICAL LABORATORY. 



other respects, the lobe in question was represented by a rudiment 

 (fig. 4), in which, however, all the parts of the perfected structure 

 were distinctly and symmetrically represented. The condition of 

 this single specimen does not afford sufficient grounds for attempt- 

 ing to make any deductions, but I direct attention to it here, as 

 the examination of further material might establish this as a 

 modification of regular occurrence, and, therefore, requiring to be 

 taken into account in any attempt to explain the uses of the 

 various tentaculiferous lobes. 



EXPLANATION OF PLATE. 



Fig. L — Spadix of mature Nautilus pompUius from the outer side 

 (natural size) 1, 2, 3, 4 tentacles, gld., glandular patch. 



Fig. 2.— Portion of surface of tentacle 4, magnified. 



Fig. 3. — Portion of the surface of glandular patch, magnified. 



Fig. 4. — Inner tentaculiferous lobes of specimen referred to in the text. 



ON THE OCCURRENCE OF DIATOMACEOUS EARTH 

 AT THE WARRUMBUNGLE MOUNTAINS, N.S.W. 



By Professor T. W. Edgeworth David, B.A., F.G.S. 



(Publication deferred for the present.) 



