Siboga-Expeditie 



Vla' 



THE 



PORIFERA OF THE SIBOGA-EXPEDITION 



II 

 THE GENUS SPIRASTRELLA 



BY 



D R G. C. J. VOSMAER 



Professor in Leyden 



With fourteen plates 



late E. J. BRILL 



PUBLISHERS AND PRINTERS 



LEYDEN — 191 I 





