PLATE LI. 



PAGE 



Fig. 1. LatnmcuUa apicalis from Kerguelen, section taken at right angles to the 

 surface, through a raised pore-area and an oscular projection; ect., 

 ectosome ; ch., choanosome ; p., pores, on the top of a raised pore- 

 area; i.e., large inhalent canal; f.c, flagellated chambers; e.c, 

 large exhalent canal, or oscular tube; o., osculum ; d., dermal 

 skeleton of discastra ; g.c, groups of glandular (?) cells in the 

 ectosome; e., embryos; x 15, . . xxxii, xxxix, xliv, &c. 



Fig. la. Small portion of section of choanosome, more highly magnified; i.e., inhalent 

 lacunae; f.c, flagellated chambers; e.c, exhalent lacunaa; e.o., opening.s of 

 flagellated chambers into exhalent lacunaj ; x 284. 



Fig. Vi. Small portion of section of ectosome, more highly magnified; d., discastra of 

 the dermal skeleton; f.t., fibrous tissue in which the bases of the discastra 

 are imbedded; v.c, vesicular cells; g.c, glandular (?) cells; x 284. 



The .•spicules are 'printed in blue. 



