142 Mr. H. J. Carter on the 



depressed. Structure, spicules, and texture the same as in 

 the foregoing families. Vents on the internal surface of the 

 excavation. Forms hollow, tubular, funnel- or vase-like ; 

 single or in groups ; or hollow compressed, vase-like or 

 flabelliform ; smooth and even internally, but covered ex- 

 ternally with aculeations or prominent eminences, as before 

 mentioned. 



Group 7. Subaculeata. 



The same as the foregoing, but with the aculeations much 

 less marked or prominent. 



Group 8. Ciliata. 



The same as the foregoing, but with the excavations tubular, 

 separate or united pandeanpipe-like into a compressed massive 

 form, fringed round the orifices of the tubular excavations. 



Group 9. Bivalvata. 



The same as the foregoing, but with the external surface 

 more or less covered with rugose eminences ; the form vase- 

 like, compressed, and thus rendered double flabellate or bi- 

 valvate ; texture leathery. 



Group 10. Complanata. 



The same as the foregoing, but cup-like, expanded, and 

 without rugae — that is, smooth on each side ; with a leathery 

 texture and, for the most part, papyraceous thinness. Allied ■ 

 inform to some of the Otahitica, among the Hircinida (see 

 footnote, p. 139). 



Group 11. Plicata. 



The same as the last, but frond-like, thick, papyraceous, 

 plicated, tending to vasiform, in a large undulating continuous 

 cloth-like sheet. Allied in form to some of the Otahitica. 



Family 3. Acervochalinida. 

 Group 12. Solida. 



The same in structure &c. as the foregoing, but massive, 

 lobed, and amorphous. 



Group 13. Clathrata. 

 The same in composition, but with a clathrous structure. 



