PLATE XV. 



FAVIA FRAGUM (Esper). 



Fic. 113. — Transverse section through tlie stomod<T?al region of a larva after six liours' extrusion. Two pairs of 



mesenteries are here complete. X 200. 

 Fig. 114.— Transverse section through the same larva, a little below the stomoda?al region. Two additional pairs of 



mesenteries (IV, IV; V, V) are developed at this level, but no trace of a sixth pair. X 200. 

 Fir,. 11.5. — Transverse section of a somewhat older larva. Three pairs of mesenteries are here comi)lete. and the 



fourth and fifth pairs extend higher than in the last larva. X 200. 

 Fig. 116. — Transverse section of the same larva a little below the stomodieal region. Six pairs of mesenteries are 



now present, filaments oc-ciirring on the first three developmental jiairs. X 200. 

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