166 CLASS III.— ORDER I. 



OTAHEITAN. 



66. Spongia Otha'itica, Crater-formed, divided, or 

 deeply incised and lobed ; incrusted with large hol- 

 lows, whose borders are raised, studded, and spongy, 

 but without incrustation. 



Australasian and Atlantic seas. 



RIBBED. 



67. Spongia costifera. Turbinated; the external 

 partitions furnished with longitudinal ribs rather sharp- 

 edged, appearing like narrow planks ; texture fibrous, 

 stiff, without incrustation. 



Southern Ocean. 



VASE-FORMED. 



6S. Spongia lahellum. In the form of a vase with 

 an elliptical opening, whose borders are undulated 

 and festooned ; sides stiff, resembling leather or 

 pasteboard, with longitudinal nerves, from which 

 spring smaller ones in trellis form. 



CUP-FORMED. 



69. Spongia pocillum. Irregularly formed like a 

 chalice, stiff like woollen cloth, partly incrusted, 

 and very porous; exterior surface finely cleft, the 

 interior more bristled or prickly, and almost gra- 

 nulated. 



Northern seas. 



VEINED. 



70. Spongia venosa. Turbinated and very wide ; 

 thin, incrusted, and reticulated ; net-work formed by 

 veins or small longitudinal nerves. 



Supposed to originate from the Indian Ocean. 



