250 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



ticurn (fig. 20, pi. 23), this flattening must be natural, and not the 

 result of mechanical pressure, for the diaphragm is so formed at the 

 ends of the elliptical aperture that any attempt to bring the colony 

 to a cylindrical form would rupture the diaphragm at these points. 

 The proportions of different colonies are various. They are as follows 

 for several of our specimens: length, 12 cm., width, 2.8 cm.; length, 

 12 cm., width at open end, 4 cm., at closed end, 2.5 cm.; length, 

 12.4 cm., width at open end, 3.5 cm., at closed end, 2.5 cm.; length, 

 9.8 cm., width, 3.2 cm.; length, 4.3 cm., width, 1.4 cm., etc. That 

 is, some colonies are relatively broader than others; some taper 

 strongly, others scarcely at all. The larger of these colonies measure 

 from 7 mm. to 10mm. in thickness. The test is either transparent 

 and colorless or more often it is somewhat flesh-colored or yellowish. 

 The test processes also show various degrees of development. They 

 may be quite absent — except for a few slight elevations — or they 

 may be large and numerous. The processes are rarely long or taper- 

 ing, but almost all show the characteristic truncation at their ends. 



The zooids do not differ in essentials from those of the subspecies 

 atlanticum. They vary greatly in shape and in size: length of aver- 

 age individuals about 4 mm.; height, from 1.2 mm. to 2.2 mm. The 

 oral processes are for the most part relatively short; the cloacal 

 cavities longer, but rarely exceeding the length of the pharanx. 

 Owing to the subsequent crowding of the buds in the older colonies, 

 the resulting zooids tend to become narrow and often quadrangular. 

 In the majority of the zooids the egg appears to mature after the 

 testis has developed. Hence we probably have here a strong tend- 

 ency toward protandry within those zooids which are rapidly bud- 

 ding, as already mentioned in connection with preceding forms. 



Our knowledge of the distribution of the form dipleurosoma is 

 probably quite incomplete. It was first found in the Gulf Stream 

 off the coast of North Carolina. We have 14 specimens from the 

 vicinity of the Philippine Islands, North Pacific Ocean, and one from 

 the South Pacific Ocean, as follows : 



Albatross Philippine Expedition, 1907-1910: 



D. 5196, Capitancillo Island Light, off northern Cebu Island; April 

 3, 1908; surface; surface temperature, 82° F. ; surface density, 

 1.02518; two specimens, Cat. Nos. 6469 (Holotype) and 6420 (Para- 

 type), U.S.N.M. 



D. 5262, Point Origon, off eastern Mindoro; June 4, 1908; surface; 

 surface temperature, 83° F. ; surface density, 1.02448; three speci- 

 mens, Cat, No. 6411, U.S.N.M. 



D. 5398, Gigantangan Island, between Masbate and Leyte; March 

 15, 1909; 114 fathoms; surface temperature, 80° F.; two specimens, 

 Cat. No. 6483, U.S.N.M. 



