3 66 



HYDROSILICON. 



III 



I 



'1/ 



GENUS 76. HYDROSILICON BRUN, 1891. 



Valve lamellar (sometimes pandu- 

 riform), being transversely and longi- 

 tudinally a pseudo-raphe, with simple 

 or double bifurcations near the ex- 

 treme curvatures of the valve. Bor- 

 der thickened, striped, covered with a 

 row of coarse beads. Striation having 

 as centre of radiation, the axes of the 

 crossing of the raphes (Brun). 



The genus includes two species, H. 

 rimosa (CM.) Brun. ( ' Amphiprora rimosa 

 CM earn) and H. mitt a Brun., which is 



represented in figure 118 in the text. 



To the description given by Professor 

 Brun., it should be added, thai when seen 

 in girdle view the H. mitra shows convex 

 valves, strongly constricted at the median 

 portion, and that the space comprised 

 between the terminal bifurcations of the 

 raphe is abruptly flattened. 



H. mitra inhabits the Indian Ocean, Australia, etc. 



Fig. 118. Hydrosilicon mitra. 



U*?M 



GENUS 77. CYMATOPLEURA 

 W. SMITH, 1851. 



Valves transversely undulate, finely 

 striate, with pseudo-raphe distinct 

 but inconspicuous. Girdle face show- 

 ing the undulations of the valve. 



Fig. 119. 

 Cymatopleura Solea. 



