PLATE 1. 



Erylus soUasii Lendenfeld. 

 Figures 1-48. 



1. — Transverse section of a lamellar part of a large dark specimen from South Molokai (race II); mag- 



nified 7.5; phot. Zeiss, planar 50 mm.: 



a, cortex; b, choanosome; c, monaxonid symbiont attached to one side of the Erylus. 



2. — Part of the surface of a large whitish specimen from South Molokai (race I, form C) ; magnified 7.5; 



phot. Zeiss, planar 50 mm. 



3. — Subcortical portion of a radial section occupied by numerous largo splierical grantilar cells, of a 



large dark specimen from South Molokai (race II); haematoxylin ; nmgnified 200; phot. Zeiss, 

 apochr. 8, compens. oc. 6. 



4. — Part of a radial section through the choanosome of a large dark specimen from South Molokai (race 



II); haematoxylin; magnified 200; phot. Zeiss, apochr. 8, compens. oc. 6. 

 5-12. — Apical views of clatlomes of triacnes; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6: 



5, of a triaene with one simple and two bifurcate clades of a large dark specimen from South Molo- 

 kai (race II) ; 



6, of a regular dichotriaene with very short end clades of a large dark specimen from South Molokai 

 (race II) ; 



7, of a regular plagiotriaene of a large dark specimen from South Molokai (race II) ; 



8, of an irregular dichotriaene-derivate in which one end clade of each of the three pairs is rerluced, 

 of a middle-sized light-coloured specimen from northeast Hawaii (race I, form D) ; 



9, of a regular dichotriaene with long end clades of a middle-sized light-coloured siieciinon from 

 northeast Hawaii (race I, form D) ; 



10, of a triaene with one trifurcate and two bifurcate clades of a middle-sized light-coloured specimen 

 from northeast Hawaii (race I, form D); 



11, of a regular plagiotriaene of a large whitish specimen from South Molokai (race I, form C); 



12, of a regular plagiotriaene of a middle-sized light-coloured specimen from northeast Hawaii 

 (race I, form D). 



13-26. — Side views of triaenes; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6: 



13, of a regular plagiotriaene with a rhabdome reduced to a short, conical protuberance, of a large 

 dark specimen from South Molokai (race II) ; 



14, of a triaene with one bifurcate and two simple clades, and a rhabdome reduced to a short, 

 conical protuberance, of a large dark specimen from South Molokai (race II); 



15, of a plagiotriaene with simple, unequal, stout, blunt clades and a regular blunt rhabdome, of a 

 large whitish specimen from South Molokai (race I, form C) ; 



16, of a plagiotriaene with equal, cylindrical, terminally rounded clades and a rhabdome bearing 

 small rounded protuberances near the end, of a large whitish sjiecimen from South Molokai 

 (race I, form C) ; 



17, of a plagiotriaene with slightly unequal, slender, blunt clades and a regular pointed rhabdome, 

 of a large whitish specimen from South Molokai (race I, form C); 



18, of an irregular orthotriaene with unequal stout clades partly rounded at the end, and a reduced 

 cylindrical, terminally rounded rhabdome, of a middle-sized light-colourecl specimen from north- 

 east Hawaii (race I, form D); 



19, of a plagiotriaene with fairly equal, slender, pointed, regular clades and a fairly pointed rhabd- 

 ome, of a middle-sized light-coloured specimen from northeast Hawaii (race I, form D) ; 



20, of a plagiotriaene with slender, regular clades, one of which is strongly cvu'vcd at the end, of a 

 middle-sized light-coloured specimen from northeast Hawaii (race I, form D) ; 



21, of a fairly regular plagiotriaene with short pointed clades, of a large dark specimen from South 

 Molokai (race II); 



22, of a triaene with one bifurcate clade, of a large dark specimen from South Molokai (race II); 



23, of a protriaene with unecjual, cylindrical clades, reduced in length and terminally roun<led, 

 of a large dark specimen from South Molokai (race II) ; 



24, of a plagiotriaene with one clade terminally recurved and a rhabdome bearing slight protuber- 

 ances near the end, of a large dark specimen from South Molokai (race II) ; 



25, of a rather stout plagiotriaene with relatively long clatles, of a large dark specimen from South 

 Molokai (race II); 



