﻿IX, D, 3 



Light: Some Philippine Scyphomedusae 



213 



a median flaplike projection from the outer margin. The sub- 

 genital porticus is cruciform and unitary. 



The mouth arms vary in length from 1.3 to twice the bell 

 radius. The proximal area, in the adult, is about 0.25 of the 

 arm length and considerably more in the immature medusa. 

 It is narrow and unbranched, and bears mouths only on its 

 inner side where they extend to the center of the arm disk. 

 The distal portion has the shape of a 3-cornered pyramid, the 

 branches of the wings of the mouth arms extending alternately 

 in opposite directions. The mouths are found only on the outer 

 surfaces of the secondary branches of the three main divisions 

 of the mouth arms, but these branches are so elongated laterally 

 as to cover the bare spaces between the 

 branches and present in all directions a 

 surface composed of fringed mouth open- 

 ings interspersed with filaments. The cap- 

 itate tentacles fringing the mouths are very 

 numerous and heavily loaded with nema- 

 tocysts. The filaments are covered with 

 large nematocyst warts, giving them a 

 knobbed and knotted appearance. The fila- 

 mentous axial terminal appendages are about 

 as long as the mouth arms and very flexible. 

 They contain a central canal, and are covered 

 with nematocyst warts considerably smaller 

 than those of the other filaments. The cen- 

 tral ducts of the mouth arms join in pairs 

 before passing into the stomach, the ducts 

 of the two arms arising from a common 

 interostial pillar uniting. Each of these 4 

 main ducts enters the outer end of a stomach 

 pouch. The main duct of each mouth arm gives off about 6 

 small branches to the mouths of the upper portion of the mouth 

 arm. At the point of origin of the two outer arm branches 

 it gives off 3 main branches, one to each arm branch, and con- 

 tinues beyond that point to the tip of the mouth arm as a small 

 central canal giving off a few small branches to each of the three 

 arm branches and is continued as the central canal of the 

 terminal filament. The canals to the two outer arm branches 

 are broad and bifurcated near their outer ends. 



The stomach is cruciform in shape, the 4 lobes tapering some- 

 what toward the outer ends. From the outer extremity of each 

 lobe there are given off 3 radial canals, a central rhopalar canal 

 and an ardradial canal on either side arising from the outer 



Fig. 5. Acromitus ma- 

 culosu8, an exumbrel- 

 lar view of a sense 

 organ ; diagrammatic. 

 Much enlarged. 



