ACTINIAN BUNODEOPSIS GLOBULIFERA. 317 



(). Vertical section tlirougli the basal jjart of a tentacle with tlic tcntaculo-ccjelomic septum attached, 

 the disc, and upper portion of the stomodaeal wall. x 300. 



7. Transverse section through a portion of the stomodteal wall, x 400. 



8. Nematooysts : a, thin-walled form from the tentacular ectoderm; 6, thick- walled form from the 



columnar evaginations ; c, from the stomodrcum ; «?, from the mesenterial filaments, x 1200. 

 !). Transverse section of a polyp with only three pairs of complete mesenteries, x 70. 



10. Transverse section of a polyp with three pairs of complete mesenteries, one moiety of another 



pair, and at one region numerous incomplete pairs. X 70. 



1 1 . Transverse section of a polyp with four pairs of complete mesenteries, a moiety of two other 



pairs, and a region with many incomplete pairs. A section of a tentacle whicli has intruded 



within the polypal cavity is represented at the upper right-hand corner. x 70. 

 I'J. Transverse section of a polyp in which for the most part hexameral regularity prevails, but at 



one region growth is proceeding irregularly, x 70. 

 13. Transverse section through part of the stomodseal region of a polyp, including the tentacular 



zone. The relations of the tentacles to the mesenterial chambers and the teutaculo-coeloniic 



septa are cleiirly shown. x 70. 

 If. Transverse section of the same polyp at a slightly lower level. Mesenterial pairs belonging to 



the first, second, and third orders occur regularly throughout the greater part of the polyp, 



but the sequence is irregular at the upper right-hand side. x 70. 

 15. Transverse section of a large polyp in which three orders of mesenteries are regularly 



developed, except on the right upper side. Most of the pairs of the second order have become 



inserted on the stomodseum. x 70. 

 Ki. Transverse section of a portion of the column-wall a little below the stomodseal region, with a 



mesentery attached, bearing a simple mesenterial filament, x 400. 



17. Transverse section of a mesentery and the portion of the column-wall to which it is attached. 



X 300. 



18. Transverse section through a trilobed mesenterial filament. x 400. 



SIX'OXl) SElllES. — ZOOLOGY. VOL. VTII. i7 



