NOTES ON SOME SPECIES OS RETEP3RA AND ADEONIiLLA 



Reteporidae. 



Genus Retepora Imperato, 

 i. Retepora pacifica japonica, n. subsp. 

 Pl. Vili., figs. 2-3. 



Numerous colonies from the shallow water near the Misaki Marine 

 Laboratory and from the deeper parts of Sagami Sea (Yodomi 6b fms.; 

 Onigasé, 120-160 fms.) are specifically identifiable with Robertson's 

 Retepora pacifica^-, but may at the same time be made to represent a 

 new variety or subspecies, which will here be called by the name of 

 japonic a. 



The Sagami Sea specimens seem to agree with typical R. pacifica 

 of the west coast of N. America in all essential points of habitus and 

 structure, except in this important respect that not all the reticulating 

 zoarial trabeculae consist of biserially arranged zooecia as they seem 

 to do in the latter, but .some of them occurring in irregular distribu- 

 tion, are simple connectives canallated in the interior and showing no 

 sign of zooecial structure. Trabeculae of this barren nature are on 

 the whole thinner than those made up of zooecia ; moreover, they start 

 from, or join with, the latter at an angle considerably wider than 

 that formed by these at the bifurcation point. So that, the barren 

 trabeculae can usually be readily distinguished from others of ordinary 

 structural composition. Further, the fenestrae in the Sagami Sea form 

 are of a rather indefinite —though generally elongate —shape and of 

 very varying dimensions, frequently reaching a length about four times 

 as long as wide ; while in the typical form they should be oval and 

 only about twice as long as wide. 



In the present form of the species I have observed that the open- 



1) A. Robertson 1 908, The incrusting chilostomatous Bryozoa of the west coast of N. 

 America. Univ. of Cal. publications in Z00L, VoL IV, No. 5. p. ,}io; pi. 24, figs. 81-84. 



