SCYPHOMEDUSAE COLLECTED BY STEAMER ALBATROSS. 



219 



thread-like filament about 50 mm. long. There are also a few shorter, 

 more slender filaments which arise from the sides of the mouth- 

 arms between the mouths. There are no filaments upon the arm-disk. 



There is a wide zone of circular muscles in the subumbrella, and 

 these are only partially interrupted in the eight rhopalar radii. 



The central stomach gives rise to 16 radial canals, 8 of which 

 extend to the rhopalia and the 8 others end in the ring canal. On 

 its inner side the ring canal 

 gives rise to 16X4 radial vessels, 

 which do not reach the margin 

 of the stomach but anastomose 

 one with another and with the 

 16 chief radial canals. On its 

 outer side the ring canal gives 

 rise to about 100 radiating ves- 

 sels, all of which anastomose by 

 side branches, forming a reticu- 

 lum in the outer zone of the 

 subumbrella. 



In formalin the gelatinous sub- 

 stance is translucent and milky, 

 and the gonads and mouth frills 

 are milky yellow. 



The following table will serve to indicate the distinctions between 

 Lychnorhiza bomensis and Lychnorhiza bartschi of the Philippines : 



Fig. 



19. — Lychnorhiza boenensis 

 Tawao, Borneo. 



L. bartschi. 



L. bomensis. 



Velar lappets 



Interradial papillae on the subum 



brella. 

 Perradial niches in the arm-disk. 

 Mouth-arms 



Filaments 



Circular muscles 



Canal system 



Central stomach 



(8X12) all oval and similar each 

 to each. 



None 



Four deep clefts 



Less than half as long as bell- 

 diameter. 



Numerous. Lateral filaments 

 as long as those at outer tips 

 of mouth-arms. Longest fila- 

 ments are upon arm-disk. 



Entire . 



Network on inner side of ring- 

 canal does not fuse with 16 

 radial-canals. 



Narrow and cruciform 



(8X7) those adjacent to rhopalar 

 iappets being twice as wide as 

 the others. 



4. 



Four wide, shallow grooves. 



About two-thirds as long as bell- 

 diameter. 



A single slender filament at outer 

 end of each arm. Other arm- 

 filaments are very short and 

 slender. No filaments upon arm- 

 disk. 



Almost interrupted in 8 principa 

 radii. 



Network on inner side of ring-cana 

 fuses with 16 radial-canals. 



Wide and cruciform. 



Genus MASTIGIAS L. Agassiz, 1862. 



Mastigias L. Agassiz, 1862, Contr. Nat. Hist. U. S., vol. 4, p. 

 1910, Medusae of the World, vol. 3, p. 677. 



152. — Mayer, 



Generic Characters. — Ehizostomata triptera with 3-winged mouth- 

 arms, which terminate in a naked, club-shaped extremity. There 

 are also smaller clubs and filaments between the frilled mouths. 



