14 Rev. T. Ilincks on the 



Fig. 4. Membramjjora aeifera, MacGillivray, form multispinata. 



Fig. 5. Membrmiipora echinus, n. sp. 



Fig. 6. Memhranipora levata, n. sp. 6 a. Ooecium. 



Plate XX. 



Fig. 1. Memhranipora exilis, n. sp. 



Fig. 2. Memhranipora Sophies, Busk, form matura. 



Fig. 3. Memhra7iipora mijiuscuJa, n. sp. 3 a. Avicularian area. 



Fig. 4. Memhranipora corniculifera, u. sp. 4 a. Zooecium with ovicell, 



showing the horn-like projection on the latter. 

 Fig. 5. Cribrilina furcata, n. sp. 

 Fig. 6. Cribrilina hippocrepis, n. sp. 6 a. Primary cell. 



[Plates XVII. & XVIII.] 



Family CribrilinidaB {continued). 



Cribrilina, Gray. 



Cribrilina radiata^ Moll. 



Form innominata : off Comshewa ; Houston Stewart Chan- 

 nel. 



Form with vihracidoid setce, not uncommon. 



[Britain, chiefly south and south-west coasts; France (south- 

 west), Mediterranean, Madeira, Gulf of Florida.] 



Some beautiful varieties of this variable species occur : the 

 form which bears vibraculoid sette is especially remarkable for 

 richness of sculpture and delicacy of structure; it is furnished 

 with a distinct (though minute) lunate pore, placed within the 

 triangular space below the mouth. This character therefore 

 is not distinctive as between the genera Microporella and 

 Grihrilinaj though it is always present in the former and very 

 exceptionally in the latter. Smitt unites these genera in one 

 family (Eschariporidse *) ; but the very peculiar structure of 

 the cell-wall in Cribrilina seems to entitle it to stand as the 

 type of a separate group. 



Family Microporellidae. 



Microporella, Hincks. 



Micro'porella ciliata^ Pallas. 



Normal and forms Californica (Busk), vibracxdifera and 

 umbonata, mihi. 



* ' Floridau Bryozoa,' part i. p. 21. 



