ART. 4 SPONGES OF CALIFORNIA DE LAUBENFELS 9 



clathrate form, and the fact that in the hitter there were not only 

 many blind diverticulations, but the number of osciiles did not 

 increase with enlargement of the colony; eleanor is precisely inter- 

 mediate between the two. Histological details : The nuclei of the 

 collar cells are sometimes placed basically, sometimes apically, 

 according to Urban. 



First type of spicules, oxeas (fig. 3, D and E) ; size, 4;u, by 105/x to 

 9)U, by 434/x. Second type of spicules, quadriradiates (fig, 3, 6') ; size 

 of ra.vs, about 9/x by 140/x. Third type of spicules, sagittal alate 

 triradiates (fig. 3, J.) ; size of rays, about 7/a by 80/*. Fourth type of 

 spicules, regular triradiates (fig. 3, .5) ; size of rays, about 7/* by 140/i. 



Remarks. — There does not seem to be any other Leucosolenia very 

 close to eleanor., although, of course, many species of this genus have 

 much in common with it. Most characteristic is the extent to which 

 it is intermediate between the characteristics formerly assigned to 

 Clathrina and those always assigned to Leucosolenia. 



LEUCOSOT ENIA NAUTILIA de Laubenfels 



Leucosolenia nautilia de Laubenfels, 1930, p. 25. 



Holotype.—JJ.S.'^.M. No. 21466; B.M. No. 29.8.22.11. 



Type locality. — A small group of California specimens was stud- 

 ied, all collected by myself, July 20, 1926, from the bottom of a 

 motor-driven fishing vessel that had been in active use near Monterey 

 Bay since its previous cleaning, about six months earlier. This 

 sponge was here associated with the introduced mussel, Mytilus 

 edulis., a remarkable circumstance. The only mussel at all common 

 locally is M. calif ornianus. 



Description. — Shape, there is a stoloniferous basal reticulation 

 from which rise separate tubes. Size of largest colony, 20 mm high, 

 35 mm in diameter. Tubes, 0.2-2 mm in diameter and about 20 mm 

 long; walls, about 50/i thick. Consistency, fragile. Color in life 

 and when preserved, white. Oscules, apical; diameters, as for the 

 tubes. Pores, about 50/i in diameter; they cause the walls of the 

 tubes to appear fenestrated. Surface, superficially hispid. 



Ectosomal specialization, none. Endosomal structure, typical 

 ascon sort. Histological details: The nuclei of the collar cells are 

 so located in the main body of the cell as to be dubiously basal. 



First type of spicules, large oxeas (fig. 4, ^), size, 10/a by 400/i to 

 20/i by 1,000/a. Second type of spicules, small oxeas (fig. 4, D and 

 E) ; size, about 4yx by 140/*. Third type of spicules, triradiates (fig. 

 4, 5) ; size of rays, about 9/x by 140/t. Fourth type of spicules, quadri- 

 radiates (fig. 4, C) ; size of projecting rays, about 8/a by 30/*, tangen- 

 tial rays as for the triradiates. 



