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This differs from typical Esperiopsis in lacking sigmas. The very 

 symmetrical ladder structure is a bit miusual, though isodictyal struc- 

 ture and fibrous structure are common in this genus. The dermis is 

 typical. The closest relative seems to be Esperiopsis glaber Br0nd- 

 sted (1924, p. 141) from New Zealand, which has exactly the same 

 architecture, but longer styles (up to 10/x by 370/a), and has three 

 sizes of sigmas. 



Figure 38. — Esperiopsis originalis de Laubenfels : Portion of 

 the skeleton. A, Maximum size of the megasclere ; B, small 

 size of the megasclere, probably immature ; C, D, micro- 

 scleres. D, x 1,333; others, x300 



Genus WILSA * de Laubenfels 



Wilsa may be defined as of the subfamily Mycalinae, for sponges 

 with smooth monaxon megascleres, palmate isochelas and forceps, 

 typically with macrosigmas as well as sigmas of the more usual size. 

 Genotype : Wilsa hyinena. 



WILSA HYMENA de Laubenfels 



Wilsa hymena de Lauejenfels, 1930, p. 27. 



HoIotype.—V.S.l!iM. No. 21515; B.M. No. 29.8.22.62. 



Type locality.— Monterey Bay, Calif., May 9, 1929, depth TOQ 

 meters, collected by E. F. Ricketts. The one specimen was on the 



* Named for Prof. H. V. Wilson, of the University of North Carolina. 



