Plate V. 



Eiqjlectella tiiarsluUli Ij. 



Figs. 29, 30. Early stages iii the development of iioricome. The principals 



inclosed in the scleroblast mass. Borax-carmine. 1000 x . 

 Fig. 31. Portion of a mature iioricome, still with the scleroLlast-mass. Borax- 

 carmine. 1000 X . 

 Figs. 32-34. Stages in the des'elopment of graphiocome. Borax-carmine. 



1000 X . 

 Fig. 35. 0[)tical section through the terminal sheaf of a develoiiing graphio- 



come. Borax-carmine. 1000 x . 

 Fig. 36. A small jwrtion from the periphery in a section through the ledge, 



showing the conuli supported hy dermal hilt-rays, the cobweb of 



trabeculaj, &c. Borax-carmine. 300 x . — a.d., archpeocyte-cougeries. 



arch., arch;eocytes. ch., fundus of flagellated chamber, s.c, subder- 



mal cavit}-. th., thesocytes. 

 Fig. 37. Chamber-wall (reticular membrane). Acid-fuchsin. 1500 x. Above, 



the membrane is shown as out of the focus; the flagella are here 



visible either sidewise or in optical sections. The central dot in 



the choanocyte nuclei represents the origin of a Hagellum. Below, 



at the right corner, four archieocytes (arch.) 

 Fig. 38. 8ame with coarse refractive granules in the [irotojilasm. Acid-fuchsin. 



1500 X . 

 Fig. 39. Apopylar edge of the chamber-wall. Borax-carmine. 1.100 x . — 



ch.n., ciioanocytal nucleus, vi.m., marginal membrane, ir., trabecula. 



tr. n., trabecular nucleus. 

 Figs. 40, 41. Choanocytes in profile view. Acid-fuchsin. 1500 x. 

 Fig. 42. Same in surface view, combined from views obtained at different 



foci of the microscope. Acid-fuchsin. 1500 x . 

 Fig. 43. Optical section showing incurreiit lacunar space between four 



chambers. Borax-carmine. 1500 x .—la.r., membrana reticularis. 



Other letterings as in figs. 3(J & 39. 

 Fig. 44. Groups of peculiar rod-like bodies (probably not belonging to the 



sponge). Borax-carmine. 1500 x . 

 Fig. 45. Trabecula from a certain specimen, with egg-like cells (,r) of various 



sizes. Borax-carmine. 1000 x . — tr.n.. trabecular nuclei. 



