ART. 4 



SPONGES OP CALIFORNIA de LAUBENFELS 



Material examined. — About a dozen specimens were studied, all 

 collected near Lagima Beach, intertidal, March 14, 1926, by myself. 

 They were found principally pendant on the underside of sandstone 

 bowlders. 



Description- (U.S.N.M. No. 21464; B.M. No. 29.8.22.49).— Shape, 

 clathrous, vasiform, pedunculate. Size, up to 4 mm in diameter, 

 8 mm in height. Consistency, fragile. Color in life and when pre- 

 serA^ed, white. Oscules, few and simple ; diameter, lOjx. ' Pores, 

 minute; diameter, about 5;u. Surface, superficially smooth, micro- 

 scopically hispid. 



Ectosomal specialization, none. Endosomal structure, ascon tubes 

 80/x to IZOfx in diameter, branching and anastomosing to make a retic- 

 ulation with meshes 70/a to 270ju, in diameter. The skeleton consists 

 of about two layers of simple triaxons. Histological details : I have 



Figure 2. — Leucosolenia macleayi Dendy : One of the ascon tubes, X300: 

 illustrating the spicules and their placement 



a preparation of this species in which the axial canals of the spicules 

 are clearly evident. This is rather uncommon in calcareous spicules. 

 Statements have even been made that calcareous spicules lack such 

 an axial canal, although Minchin (1900, p. 40) calls attention to the 

 fact that there really is one. 



Principal spicules, triaxons (fig. 2). Size of each ray, 3/x by 40/* 

 to 6ja by QO/x ; the usual size is 6/x by 40/i. 



Remarks. — There are rather few Leucosolenias having only triradi- 

 ates, but some of these, including the present species, are common and 

 nearly cosmopolitan. L. macleayi is characterized by delicate lacy 

 form, regularity, and simplicity of spiculation, and by the stipitate 

 habitus. I wish to thank Maurice Burton, of the British Museum 

 of Natural History, for help in allocating this species, as by a mistake 

 I had identified it with the rather similar Leucosolenia coriacea 

 Montagu. L. coriacea differs in that it always has more repent form 

 than macleayi. 



