NO. 2247. SPONGES FROM NORTHWESTERN PACIFIC— SOZ AW A. 



527 



pseiidopores are, as usual, circular, with a diameter of 150-500/i. The 

 ascon tubes are 150-450|U, wide. The inner surface of the wall is 

 perforated by numerous small oscula of lOO-TOO/i, diameter, each 

 leading into a single or more gastral cavities of the ascon tubes. 

 The prosopyles are circular appertures of about 20/* diameter. 



The color of the sponge in alcohol is white, with a slight yellowish 

 tint. Under the microscope there are visible in the wall numerous 

 spherical granules of a yellowish color and with a diameter of 4-12]u. 

 The sponge readily falls into pieces, being of a very delicate texture. 



The skeleton consists of triradiates, quadriradiates, and oxea. The 

 main part of the ascon wall is composed of triradiates and quadri- 

 radiates, both of which are arranged promiscuously in a single layer, 

 the apical rays of the latter projecting into the gastral cavity, but 



Fig. 1. — Ledcosolenia albatrossi. a, TniRADiATES of ascon-tdbe. h, quadriradiate 



OF ASCON-TnBE. C, OXEA OF ASCON-TUBE. c' , SAME SEEN FliOM SIDE. d, TRIRADIATE 

 OF THE LINING LAYER OF PSEUDOGASTER. 6, QUADRIRADIATE OF THE LINING LAYER OF 

 PSEDDOGASTER. AU X 300. 



otherwise without any definiteness in the orientation of the rays of 

 both. The skeletal layer lining the pseudogaster, and having a thick- 

 ness of nearly 40/x, is made up of a somewhat different kind of tri- 

 radiates and quadriradiates, both of which are fairly closely arranged 

 in a few layers, the apical rays of the latter projecting into the 

 pseudogaster. The oxea occur in a few number only in the outer 

 parts of ascon tubes, running parallel to the tube surface, but show- 

 ing no rule as to the direction they take. 



Spicules (fig. 1). — ^Triradiates of ascon tubes {a) slightly sagittal, 

 with paired rays slightly longer than basal ray. All rays are of 

 equal thickness. Paired rays very slightly curved, often somewhat 

 crooked, sharply pointed, 80-100/a long and 8/x thick at base. Basal 

 ray straight, tapering gradually to sharp point, 70-90/;i long and 8/* 

 thick at base. 



