PLATE XTTT, 



SOLENASTR^A HYADKS (Dana). 



Fig. 91.— Transverse section through another bud piilyji of Stilfiiiislr:ni, showing file proportional (levelo]inient of the 

 mesenteries. (See \>. 500. ) X 100. 



FAVIA FRAGITM (ICsper). 



Fkj. 02.— Section of aboral surface nf a decalcitied polyp; the lateral invaginations correspond with the various' 



septa, and the middle with the skeletal processes from the Hoor of the calice. No hexameral regularity 



can be established. X H. 

 Fi(i. 9.S. — Transverse section of a polyp through the stomoibeal region, showing the irregular arrangement (if the 



mesenteries and septal invaginations. The latter are mainly entoc«elic. X 45. 

 Pi,;. 94.— Tangential section through a mesenterial filament in the lower region. The middle jiart is .rowded with 



large nematocysts. X oSO. 

 Fi(i. 95.— Section through a mesentery along the edge by whicli it is adherent to the corallum. Conical or 



wedge-shaped desmoidal processes {ih's. pr.) extend all tlie way, some of them lieing cut transversely 



toward the lower part of the section. X 320. 

 Fid. 95a.— Transverse section through a mesentery, just below the stomoda^um. Tlie mesenter\- is divided into 



two parts by a discal invagination which appears as a canal. (See p. 434. ) X 70. 

 Kios. 9(i-100.— Larva'. Figs. 9fi-99 represent the various forms of the larvfe immediately after extrusion; fig. 100 



with file oral pole swollen and the aboral narrow, the form often assumed a day or two after extrusion. 



Fig. 90 is viewed as a transparent object, tlie others by reflected light. Extrusion of cell debris is 



represented as taking place from the oral aperture in tig. 96. Enlarged. 

 FiG. 101. — Form assumed by larva which never attained fixation. 



Fig. 102. — A free swimming larva, about 10 days old, in which twelve tentacular prominences occur. 

 Fig. 103. — A larva shortly after settling. The larva is now tlaftened, but non-transparent, and only f.mr pairs of 



mesenteries are indicated on the outside. 

 KiG. 104. — Upper view of a distended, non-transparent larva, a few hours after settling. The twelve mesenterial 



chambers are already formed. 

 624 



