76 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



Principal spicules, smooth styles (fig. 41, G) ; size, 25/a by 350/t. 

 Secondary spicules, styles with spiny heads (fig. 41, 5) ; size, 20/x by 

 840/A. Ectosomal spicules, tornotes (fig. 41, A)\ size, 5/x by 205/x. 

 Microscleres, arcuate chelas (fig. 41, Z>) ; length, 25/i, to 30/*. 



Remarks. — This species is peculiar for having only the one sort 

 of microsclere, and the disproportion between the ectosomal and 

 endosomal spicules is not common. 



Similar species of this genus are reported from all parts of the 

 world. 



LISSODENDORYX NOXIOSA de Laubenfels 



hissodcndoryx noxiosa de Laubenfels, 1930, p. 27. 



Holofypc.—V.S.'NM. No. 21467; B. M. No. 29.8.22.14. 



Tppe locality.— Paciac Grove, Calif., intertidal, July, 1925, col- 

 lected by me. This species is very abundant in the Monterey 

 region, growing in a variety of situations in the intertidal zone, but 

 most frequently in crevices or under rocks. 



Description. — Shape, amorphous. Size, at least 10 cm high and 

 15 cm in diameter. Consistency, spongy. Color in life, yellow ; pre- 

 served much paler, nearly colorless. Oscules, there may or may not 

 be present surface openings or depressions of very irregular size 

 and shape, which may or may not be oscules or pores or neither or 

 both. Pores, see remarks above. Surface, primarily smooth but 

 with more or less abundant irregularities in the form of both lumps 

 and pits. 



Ectosomal specialization, a dermal membrane, about 30/* thick; 

 so contractile that it is difficult to study the afferent and efferent 

 openings. It is in places easily detachable, but upon removal it 

 contracts so vigorously as to preclude satisfactory study. Else- 

 where it is very difficult to remove it. Apparently it contains few 

 megascleres, the dermal spicules being employed to support it. 

 After its removal the interstices of the endosomal reticulation are 

 exposed with here and there irregular larger apertures. Endosomal 

 structure, " crumb-of -bread," with a dense isodictyal reticulation of 

 the styles; meshes usually triangular. The styles are often side by 

 side, so placed as to outline chambers with walls having some re- 

 semblance to those of old-fashioned log cabins.. 



Principal spicules, styles (fig. 42, B, C) ; size, 10/x by 180/x to 12/i 

 by 200/1. These styles almost always have about two to four rather 

 large spines; occasionally they have as many as six or eight, and 

 also a few are entirely smooth. The spines are rather more often 

 to be noted on the heads than on the shafts. Very thin forms of 

 both sorts of megascleres are met with, probably immature stages 

 (fig. 41, D). Ectosomal spicules, tylotes (fig. 42, 4) ; size, 4/i by ISO/i 



