40 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 81 



relationship to the Homosclerophora. Toxas were found in huch- 

 landi, and I can report a few in synnafitus, but I consider them in 

 both cases foreign inclusions, as were certainly three chelas of two 

 different sorts, five sigmas, and some broken tjdostyles that were in 

 syrmatitus. 



Family TETILLIDAE Sollas 



Genus TETILLA O. Schmidt 



TETILLA MUTABILIS de Laubenfels 



Tetilla mutaMlis db Laubenfexs, 1930, p. 26. 



Holotype.—V.S.'NM. No. 21498 ; B.M. No. 29.8.22.33. 



Type locality. — Newport Harbor, near San Pedro, Calif., Novem- 

 ber, 1924, collected by me. The species occurs near, often just 

 below, extreme low-tide mark. 



Occurrence. — I know of no specimens of the sponge from any 

 other locality than the mud flats around Balboa Island in Newport 

 Harbor. The massive forms lie loose on the soft mud, the clavate 

 forms seem to have been attached to small shells or other solid ob- 

 jects. In November, 1924, I found the massive form amazingly 

 abundant, mostly sponges the size of a fist or larger, and nearly 

 every square meter had a specimen; there must have been literally 

 bushels in sight. 



In June, 1926, a visit to the same locality failed to yield a single 

 specimen, in spite of a careful search at a very low tide, but in 

 November, 1926, the species had again become common. Hard rains 

 occur in this vicinity during winter, and it would seem probable 

 that the great influx of fresh water, which then, but only then, runs 

 into this harbor, would greatly lower the salt content over these 

 flats. A rain at low tide would drench the sponges then exposed. 



Description. — Shape, pedunculate-clavate to irregularly massive. 

 Size, up to 8 cm high and 15 cm in diameter. Consistency, mod- 

 erately spongy to cartilaginous. Color in life, dull red with green- 

 ish glints (due to algae ?) ; dry, gray; in alcohol, dull red. Os- 

 cules, oval, flush, about 2 mm in diameter; usually several centi- 

 meters apart. Pores, well under lOO/i in diameter, very difficult to 

 find. Surface, superficially hirsute with repent, exceedingly thin 

 spicules matted or felted together. 



Ectosomal specialization, not evident, other than that mentioned 

 above. Endosomal structure : 



I. Structure of clavate form. My largest specimen of this form 

 was 22 mm high and 12 mm in diameter. Those of this form are 

 typically much smaller than that. There is a central axis about 

 500/A thick, through stem and body, consisting of densely packed 



