182 CRIBRILINID^. 



Habitat. Very small stones in deep water. Mr. Nor- 

 man says : — '' This very distinct little species has a very 

 peculiar habit ; it is never found on any but the smallest 

 stones. I do not remember to have ever seen it on a 

 pebble larger than the little-finger nail ; more generally 

 it selects those that are not more than a fourth of that 

 size." 



Locality. Shetland (Barlee) : ibid.^ in 80-110 fathoms 

 (A. M. N.). 



Geographical Distribution. Bergen (A. M. N.). 



In this species the vibracula seem to be always present^ 

 alternating regularly with the zooecia throughout the 

 colony. They reveal very clearly their homological nature, 

 as modifications of the ordinary cell. The vibracular cell 

 is in many respects a copy in miniature of the zooecium, 

 presenting the raised margin, the lamina, and the equiva- 

 lent of the orifice, the setiform appendage taking the place 

 of the oral valve. 



Family X.^ — CribriliuidaB. 



EsCHARiD.t; (piirt.), Johnston. 

 Membranipouid^ (part.), Busk. 

 EsCHARiPORiD.E (part.), Smitt. 

 EscnARELiiiD^ (part.), D'Orbigny. 



ZoARiUM aclnate, forming an indefinite crust, or erect. 

 Zocecia having the front wall more or less fissured, or 

 traversed by radiating fuiroivs. 



The CribrilinidcB form a section of the large and miscel- 

 laneous assemblage of forms included in the genus 



