NO. 1 DICKINSON : SPONGES OF GULF OF CALIFORNIA 35 



The microscopic structure shows a plumose development with tracts 

 of tylostyles pointing upward. Deep in the sponge the tracts are as much 

 as 160 IX in diameter, perhaps larger. Near the surface these break up into 

 smaller tufts about 30 /x in diameter and protrude slightly from the 

 surface. 



The megascleres are tylostyles with well-developed heads at least 

 twice the diameter of the shaft. Occasionally they show the double tylote 

 modification. The average size is 10 /x to 12 /a by 380 /x. One was found 

 that was 12 |U by 810 /x, while a few juveniles only 5 /x by 210 /a are to be 

 found. The great majority, however, are very near the average. 



The microscleres are unique. They are long and sinuous. They might 

 be termed spirasters with a strongylote modification on the spines if we 

 enlarged the term spirasters to include curvature only in one plane or 

 nearly in one plane such as occurs in toxas. They might be termed spiny 

 toxas except that there are alwaj^s two distinct curvatures, sometimes 

 three or four, instead of one. Furthermore, the spines are very large; 

 indeed, they are often fully the size of the main shaft and not tapering. 

 Another peculiarity is the branching, which is common near one or both 

 ends, usually at the apex of a curve. These branches commonly have an 

 enlarged end. Perhaps the best term to apply would be strongylote tox- 

 asters, although one should keep in mind that the curvature is not confined 

 to the simple one of a toxa but is often multiple. The microscleres are 

 located throughout the sponge and vary from 18 to 40 /x in length. 



Holotype. — AHF no. 19. 



Type locality. — Outside Concepcion Bay, Lower California, Mexico ; 

 24 m ; corallines. 



Distribution. — Same. 



Material examined. — 

 Sta. 683-37 Concepcion Bay 3-15-37 24 m 



Remarks. — ^This genus resembles Spheciospongia in the tendency to 

 grow into a cakelike mass. There is some evidence of relationship also, to 

 Alcyospongia india de Laubenfels from the West Indies. This genus, 

 however, has a distinct stalk, is spherical, and has oxeas instead of tylo- 

 styles. The microscleres are spiny rhabds, which are not curved. 



Choanites mineri is somewhat similar, having the t3dostyles of approxi- 

 mately the same size and the same general architecture. The microscleres, 

 however, are centrotylote microstrongyles, usually microspined. They 

 look nothing like the microscleres of this new species. Numerous other 

 genera of this family have peculiar microscleres but none which approach 

 those of this species. 



