486 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



In listing the small specimens from Bunas Island (see above) as 

 young forms, I would add that they may be young in respect to time, 

 or possibly only in respect to growth stage regardless of actual time 

 age. I have in mind such cases as that of Microcioma prolifera 

 Verrill (see George and Wilson, 1919), in which species we find thin 

 incrusting forms and erect ramose forms together with intermediates, 

 all breeding. The abundance of the incrusting type in Beaufort (X. 

 C.) harbor, coupled with the comparative scarcity of the ramose 

 forms, makes it probable that the sponge very often stops its 

 growth, owing to environmental conditions, in the incrusting stage. 

 Incrusting Microcionas may therefore, on this hypothesis, sometimes 

 be quite as old in time as many a ramose specimen. 



EUSPONGIA IRREGULARIS Lendenfeld, var. SURIGANENSIS, new variety. 



Eusyonriia irregularis Lendenfeld, 1S89, p. 245. 



Station D5478 (vicinity of Surigao Strait), one specimen with 

 an attached Myriastra siemensi. Sponge an amorphous, thin, flat- 

 tened mass sending off subcylindrical branches which, in part, fuse 

 with one another, thus producing a very irregular body. Dimensions 

 of whole sponge 150 by 60 by 50 mm. Branches 5-10 mm. in diam- 

 eter, length of longest free branch 50 mm. Oscula 3 mm. in diam- 

 eter scattered over upper and lateral surfaces; all elevated more 

 or less, the elevation in a few cases low, in most cases forming a 

 tubular projection (cloaca! tube) 8-13 mm. high by 3-4 mm. in 

 diameter. Wall of cloacal tube very thin, inclosing a single cavity 

 into base of which open several efferent canals. Osculum at apex 

 of the tube is open in a number of cases ; in others closed, but other- 

 wise such tubes are like the open ones. In all about 20 such tubes 

 are present. Surface of sponge in general with conuli 2-3 mm. 

 apart and 1 mm. or less in height. Conuli over much of the surface 

 interconnected by the usual sharp ridges with depressed areas be- 

 tween; distinctness of ridges doubtless varies with the contraction 

 state. There are numerous smooth aconulous areas, several of them 

 extensive: all apparently on sheltered parts of the surface. Sponge 

 not as uniformly dense as E. officinalis. Color, lead gray, variable. 



Dermal membrane is smooth, without sand, but containing plenty 

 of spicule fragments ; underlaid by subdermal cavities visible to eye. 

 There is the usual dermal reticulum of fibrous bands with pores in 

 the meshes, the larger interconular bands containing a good many 

 spicules arranged lengthwise and looking almost like skeletal fibers. 

 Flagellated chambers 40-44 by 30-36 [x. 



Main fibers terminating singly in the conuli, mostly 42-56 y. thick, 

 expanding here and there to as much as 77 y. thick; 2-3 mm. apart at 

 surface, closer together in interior; containing no sand, only spicule 

 fragments; these filling the fiber in the conuli, but less abundant in 



