SILICIOUS AND HORNY SPONGES WILSON. 367 



Anatriaenes with completely degenerate clads, the spicule ending 

 distally in a knob, occur less frequently than in Hentschel's specimen. 

 Intermediates between these and the regular anatriaene also occur. 

 In some of them only one or two clads are completely degenerate. 

 In others one or two clads are simply shorter than the normal. In 

 the related Tethya coactifera Lendenfeld (1906, p. 75) the triaenes 

 exhibit similar variations to those of this species. 



The sigmas are abundant, simple contort, 14-16 y. long (7-11 ^ in 

 the type specimen). 



TETILLA (CINACHYRELLA) CRUSTATA, new species. 



Plate 39, fig. 5 ; plate 48, fig. 5. 



Station D5152, 10 specimens; station D5134, 1 specimen; station 

 D5179, 1 specimen; station D5478, 4 specimens; station D5337, 1 

 specimen. 



Body massive, somewhat flattened, often greatly flattened, from 

 above downward, with rounded or polygonal equatorial outline; 

 sometimes nearly spheroidal; pyriform in youth, with the small end 

 up. Vertical thickness of body ranges from slightly less than to 

 one-half the greatest horizontal diameter, which in these specimens 

 measures 40 to 75 mm. Under surface generally torn and then 

 showing the radiating skeletal bundles. Perfect specimens show that 

 even in the subspheroidal individuals this surface is generally flat- 

 tended ; nevertheless in one such specimen it is more convex than the 

 upper surface. It bears root spicules which in one of the adults 

 (70 mm. in horizontal diameter), doubtless representing the normal 

 condition, are abundant over the marginal region of this surface. 

 These spicules together with the entangled sand are matted together 

 into a mass 10 to 20 mm. thick. In the other specimens the root 

 spicules are inconspicuous, doubtless having been broken off. 



The surface in general often appears smooth, or nearly so, to the 

 eye, but in other places or specimens is covered with a thin in- 

 crustation of sand. Examination shows that the megascleres of the 

 radial bundles normally project a short distance, about a millimeter 

 or less. The radial bundles are so abundant in many places that 

 their projecting spicules form a practically continuous covering, 

 which of course catches sand. In other places there are pretty large 

 intervals between the radial bundles, and, although in the intervals 

 there are some medium-sized and small projecting oxeas, over such 

 parts of the surface whatever fur there is, is scanty even in the 

 natural unrubbed state. Smoothness of the surface in general is of 

 course largely due to the fact that the projecting spicules have 

 been rubbed off. Several of the specimens are infested with small 

 brown actinians, which project from the surface. 



