ART. 4 



SPONGES OF CALIFORNIA DE LAUBENFELS 



43 



Maximum lengths are probably more than 5 cm. Many of the 

 spicules seem to reach from the center of the sponge to a point 

 several millimeters past the surface of the sponge, from which 

 circumstance one is led to conclude that they may continue growth 

 as the sponge enlarges, and that this increment must be added only 

 at the deeply embedded end. Microscleres, spiny sigmas (fig. 19, A, 

 J-0) ; length, 7/t to 9/x, located throughout the sponge. Only with 

 oil immersion can they be seen to be microspined. One end is often 

 slightly tylote; sometimes both ends are. This spicule need only 

 have somewhat large spines to become a spiraster. 



A/ N -<:t>j (^ Q 



Figure 19. — Tetilla arh de Laubcnfels : A-I, X300; others, X 1,333. C, termi- 

 nation of the more slender sort of oxea, and of the esactinal ends of the 

 triaenes 



Remarks. — Lambe (1893, pp. 34, 35), records two Tetillas from the 

 vicinity of Vancouver Island, but neither seems at all close to the 

 California species. Both the Canadian forms had the special dermal 

 oxea for which certain recent authorities (see George and Wilson, 

 1921) would retain CranieUa; their placement and size of spicules 

 are also consistently different. For example, T. spinosa., the one of 

 more southerly distribution of the two, has its megascleres in a 

 whorled or spiral placement, and microscleres half again as long as 

 in T. arh. For both of Lambe's species he mentions no spines on the 

 microscleres, nor the tylote endings, but his figure for T. spinosa 

 seems to show such. Both his species have conspicuously villous or 

 conulose surfaces, strikingly absent in the California forms. 



I agree with all recent writers in merging TethyopsiUa with 

 Tetilla, from which it differed only in lack of microscleres. It is 



