TRITICELLIDJi:. 541 



family YIL— TriticellidsB. 



Triticellid.e, G. O. Sars. 



Vesiculariad.e (part.), Alder. 



HirruKARiAD/E, Busk (for the genus Hippuraria), 



ZocECiA horny, with an aperture and membranous area on 

 the ventral aspect ; borne on a rigid peduncle, to which 

 they are attached by a movable Joint, deciduous. 



One of the characteristics of this remarkable group is the 

 presence of an aperture or area, with a membranaceous 

 covering, on the ventral aspect of the cell. This is the 

 representative (as before remarked) of the aperture which 

 exists in many of the Cheilostomata, and may remind us 

 especially of the form of it which m'C find in the genus 

 Aetea. Through this genus, on the one hand, and Triti- 

 cella and Cylindrcecium on the other, as Smitt and G. O. 

 Sars have already pointed out, the two great divisions of 

 the Ctenostomata and Cheilostomata are very closely and 

 firmly linked together. 



Sars goes so far as to place Triticella amongst the 

 latter; but the Ctenostomatous character seems to me 

 to preponderate in this form, and the Cheilostomatous in 

 Aetea. 



The presence of a setose operculum and a corneous 

 ectocyst, and the absence of an oral lid or valve, are emi- 

 nently characteristic of the present suborder ; and in all 

 these points Triticella is Ctenostomatous. The aperture 

 is a prevalent Cheilostomatous character ; but Triticella is 

 not the only Ctenostome which possesses it. It exists 

 also in Buskia and Mimosella, and may probably be de- 

 tected in other forms. 



The members of the present family live in most cases as 

 commensals on various species of Crustacea. 



