NO. 1 DICKINSON : SPONGES OF GULF OF CALIFORNIA 15 



Family Gyamonidae de Laubenfels 



Genus GYAMON Gray 



Gyamon argon, new species 



Plate 19, Figs. 37, 38 



Diagnosis. — This sponge is bushlike in appearance. It covers an area 

 of 4 by 2 by 3 cm. The preserved specimen is dark brown in color. The 

 consistency is firm and corklike, and the surface is extremely uneven and 

 covered with branchlike projections 1 cm long by 1 mm in diameter. The 

 entire surface is hispid to 500 ix. Neither pores nor oscules can be found. 



The main mass of this sponge consists of closely packed triacts covered 

 with low, blunt spines especially at the ends, which are rounded. Two of 

 the rays of the triacts are much longer than the third, being on the average 

 25 /t by 125 IX, while the third ray is only 25 /x long although almost as 

 thick as the longer rays at its base. Occasional triacts are found which 

 lack the blunt spines. Very long interstitial smooth styles are also present. 

 These are 27 ix by 400 /x minimum and probably much longer, as most of 

 them are broken. Another type of spicule occasionally found is long, 

 smooth, and wavy. This type is so regularly broken that its exact nature 

 is difficult to determine, but it is at least 42 /* by 325 /a and appears to be 

 stylote. 



Holotype. — AHF no. 6. 



Type locality.— ?>o\xt\i Bay, Cerros Island; Lat. 28° 05' 20'' N, Long. 

 115° 18' 40" S ; 24 m ; rock close to kelp beds. 



Distribution. — Same. 



Material examined. — 

 Sta. 287-34 Cerros Island 3-10-34 25 m 



Remarks. — This new species is very distinctive, being completely un- 

 like the genotype, which has mostly tetractine spicules (instead of triactine 

 spicules) with all rays of equal length. It is perhaps most like Cyamon 

 neon of southern California, but that sponge had only the short ray of 

 the triacts spined, and both triacts and tetracts which are often oxeote. 

 C. neon is also a massive sponge without the peculiar surface specialization 

 found on the new species. There are also numerous differences in spicule 

 size. 



Genus TRIKENTRION Ehlers 



Trikentrion helium, new species 



Plate 20, Figs. 39, 40 



Diagnosis. — This sponge is 7 by 5 by 5 cm. It is made up of undulat- 

 ing or corrugated sheets, which are rather thin and attached at one edge. 

 The texture is woody and somewhat brittle. The color in alcohol is drab 

 throughout. A thick spicule brush covers the surface to a depth of 3 mm 

 in many places. 



