ABT. 12 HEXACTIXELLID SPONGES OKADA 7 



Kagoshima Gulf, at a depth of 103 fathoms (Station 4936). It 

 is closely allied to the type of the species in essential characters but 

 differs from it chiefly by having an ovoid mesamphidisk and a dif- 

 ferent kind of large uncinate. The sponge has the shape of a rad- 

 ish, its maximum transverse diameter at the upper end much exceed- 

 ing its height; it measures 51 mm, becoming somewhat attenuated 

 below and measuring 33 mm at the base. The oscular margin is 

 nearly circular, with an axis of 35 mm. The upper surface is occu- 

 pied by a concave sieve plate, the margin of which forms a slightly 

 raised and sharpened edge, from which the short and weak marginal 

 cuspidates protrude in a single row. The lateral cuspidates, which 

 project radially from several points on the sides of the sponge, form 

 small bundles each of several spicules. Most of these are stout and, 

 grouped together, form a small strand protruding several centime- 

 ters from the body surface. 



The root tuft is about 35 mm long. The basalia composing it 

 are an-anged in a large bundle 23 mm thick. The upper ends of 

 these spicules, which are smooth and gradually drawn to a point, are 

 imbedded in the sponge for a length of several centimeters. Their 

 much longer free part extends more or less obliquely downward. 

 The basalia have two teeth rising from the gently bow-shaped, 

 rounded, and thickened terminal portion, and end in simple conical 

 points. The distance between these two terminal points — that is, 

 the total breadth of the anchor — is 0.35 mm to 5 mm. The shaft 

 becomes gradually narrower to within a certain distance of the end 

 of the anchor, and then increases in thickness on the anchor itself. 



In the present specimen the distal ray of the dermal pinules on 

 the lateral side attains a length of 200/x, and that on the sieve plate, 

 though similar to the dermal in shape, may be much longer than it. 

 The four basal rays are longer than those of the type of the species, 

 measuring lOO/n. On some parts of the oscular sieve plate much 

 shorter pinules, measuring 85/x, are found. In these the distal un- 

 paired pinular ray is covered with moderately stout, conically 

 pointed, and widely diverging spines, 52/i in breadth. The basal rays, 

 "which form a rectangular cross, are much longer, measuring 180/x to 

 200/J,. They are stout and straight, and are often nearly covered 

 distally with short spines. A slight curvature of the basal rays may 

 sometimes appear on these pinules. The proximal ray is represented 

 by a vestige in the form of a terminally pointed short tubercle. 



As to the amphidisk, I have found moderately broad, nearly ovoid 

 mesamphidisks, which are sparsely developed among the hypoder- 

 malia and parenchymalia. Among the latter they occur much more 

 abundantly than among the former. Each spicule usually measures 

 80/* to 120/A in length and bears on each end 12 sharply pointed 



