NO. 1 DICKINSON : SPONGES OF GULF OF CALIFORNIA 31 



abundant and average 150 /x in diameter. There is a veiy tough membrane 

 present over cavities. This membrane contains no spicules. 



The specimen, as is typical of Jdreissa, has only styles. These are 40 /x 

 by 2,000 [X in the flesh, w^ith smaller ones organized in the tract. 



Holotype. — AHF no. 16. 



Type locality. — San Jaime Banks, off Cape San Lucas; Lat. 22° 50' 

 30" N, Long. 115° 15' W; 240 m; granite rocks on the bottom. 



Distribution. — Same. 



Material examined. — 

 Sta. 619-37 San Jaime Bank 3-3-37 240 m 



Remarks. — No other member of this genus has such enormous styles ; 

 and, vv^hile the extreme simplicity and consequent similarity of species 

 here placed make many species seem unnecessary, still this represents an 

 extreme without intermediates and therefore justifies the erection of a 

 new species. 



Genus HYMENIAGIDON Bowerbank 



Hymeniacidon adreissiformies, new species 



Plate 55, Figs. 109, 110; Plate 56, Fig. Ill 



Diagnosis. — ^This specimen is tan in color when preserved in alcohol. 

 It is cartilaginous in consistency and appears to be a fragment of a larger 

 encrusting mass. 



There is a distinct cortical layer which averages 100 /i, in thickness. 

 This is semidetachable, and there are subdermal cavities. The specimen 

 is not hispid. The surface has many craterlike structures irregularly 

 placed, some of which contain oscules. There are about 35 oscules on the 

 fragment, which range in size from 1 mm to 4 mm. Many ascending 

 canals are present, which give the cross section of this sponge the appear- 

 ance of vertical structure. 



The only spicule type is a smooth style, which is abundant and strewn 

 in considerable confusion throughout the flesh. The styles are peculiar 

 in their very abrupt, rounded ends, which give the appearance in some 

 instances of being cleanly cut away. Indeed, that was the first impression 

 recorded when the specimen was examined, but closer study revealed that 

 all the spicules were of the same length, whether rounded or sharply 

 truncated. The pointed end of these styles approaches the tornote modi- 

 fication. 



Holotype. — AHF no. 17. 



Type locality. — Middle San Benito, Lower California, Mexico; from 

 the shore. 



