PACIFIC TUNICATA OF U.S. NATIONAL IVIUSEUM 



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a 



Figure 25. — a, b, Dtdemnum (Polysyncraton) sagamiana Tokioka: a, spicule, X 1800; 

 b, atrial languet. c-f, Dtdemnum (Polysyncraton) semifuscum (Sluiter): c, common 

 cloacal aperture; d, spicule, X 940; e, part of spicule from another colony; /, atrial 

 languet, posterior side. 



abdomen 420-450/a in length. Atrial languet very large and bifur- 

 cated. Intestine not strongly curved. 



Remarks. — Zooids having a very stout atrial languet and the exist- 

 ence in some colonies of spherical spicules, up to about 50ju, in diameter, 

 seem to be sufficient reasons to put the present specimens under Di- 

 demnum (P.) semifuscum, although the common cloacal aperture is 

 not described on Sluiter's specimens. It is not impossible that D. (P.) 

 sagamiana is included in this species, as the spicules of tlie former can 

 be regarded as being in a dissolving phase of those of the latter. How- 

 ever, the difference found in size and appearance of the spicules is 

 notable and the existence of the charact eristic common cloacal aperture 

 in the present species is unique. It might be better, at present, to 

 retain D. (P.) sagamiana as a distinct species until some intermediate 

 forms connecting the two species are found. 



