Figs. 537-548. — Pinnule tips of various comatitlids, 537. Crossometba iNVEsnaATORis, i.ateuai. viisw. 

 538. Same, dorsal view. 539. I'tECiLOMETRA scalaris, lateral view (drawi.nu bv althorj. 

 540. Same (dkawi.no bt author). 541. Same (drawing bv author). 542. Same, (drawing bv 



AUTHOR). 543. nELIO.METRA OLACIALIS, FROM VOUNQ 3PECIME.V, L.tTERAL VIEW. 544. HELIOMETBA 



clacialis, TIP OF P,. 545. Same. 546. Same. 547. Helio.metra glaciams, from a vduxg .specimen, 



dorsal view. 548. HELIOMETRA OLACIALIS, PROM VOUNQ SPECIMEN, LATHBAL TTBW. 



289 



