Meduse of the Philippines and of Torres Straits. 189 
ring-canal which is beneath an annular furrow or bend in the subumbrella 
13 mm. inward from the bell-margin. On its inner side the ring-canal gives 
rise to from 4 to 7, usually 5, centripetal canals between each successive pair 
of radial-canals. These centripetal vessels anastomose with one another and 
with the 16 radial-canals, and end blindly before reaching the stomach margin. 
On its outer side the ring-canal gives off a network of vessels which ramify 
through the lappets. In formalin the medusa is opaque milky white;with 
irregularly clustered brown spots over the exumbrella. 
Fia. 5.—Catosiylus townsendi, from off Mount Putri, Borneo, September 30, 1909. 
This medusa is closely related to Acromitus maculosus Light (1914, Phil- 
ippine Journal of Science, vol. 9, No. 3, sec. D, p. 212, figs. 4-6), but it has no 
filaments upon its mouth-arms. It is possible, however, that these were lost, 
but this seems improbable among 6 well-preserved specimens. 
Moreover, in Catostylus townsendi the centripetal vessels anastomose with 
the 16 radial-canals, whereas in Acromitus they join only with the 8 rhopalar 
canals. It seems probable, therefore, that Catostylus townsendi is a distinct 
species separate from Acromitus maculosus Light, and that Acromitus is a genus 
derived from a mutation from Catostylus. 
