Polyzoa of the Adriatic. 311 



Familj Cylindrceciidse. 



Cylindececium, Hincks. 



Cylindrcecium giganteum, Busk. 



Range. Britain ; Naples j Queen Charlotte Islands j Mer- 

 gui Archipelago. 



Family Triticellidae, G. O. Sars. 

 HiPPURARIA, Busk. 



Hippuraria verticillata^ Heller (sp.). (PL IX. figs, 8.) 



V^alkeria verticUlafa, Heller, op. cit. (1867). 



? Lagenella nutans (part.), Joliet, Bryoz. des cotes de France, p. 101 

 (1877). 



There can be no doubt that the species to which Prof. 

 Heller has given the above name belongs to this family. At 

 the time when his work on the Polyzoa of the Adriatic was 

 published G. O. Sars's admirable paper on the genus Triticella 

 had not appeared, and the peculiarities of the type were 

 really unknown. The species occurs abundantly in Dr. 

 Pieper's collection on seaweeds. 



The stem is altogether repent and jointed at intervals ; 

 below each joint the stem is somewhat enlarged and is flanked 

 on each side by a nodular swelling, from which a branch is 

 given off. At each joint a group of cells is placed (PI. IX. 

 tig. 8 a). The zooecia are elongate- ovate, slightly curved 

 outwards on one side, and on the other (the ventral) somewhat 

 compressed and flattened. The ventral face is occupied by a 

 membranous area, which extends from the top almost to the 

 base of the cell, the orifice is terminal. The cells are borne 

 on an extremely short peduncle, to which they are jointed, so 

 as to secure a certain amount of mobility (PI. IX. fig. 8). 



The structure is altogether that of the IViticellidoi^ and the 

 species should probably be referred to the genus Hippuraria^ 

 in which the cells are aggregated in whorls (in the erect 

 form) or in groups, as in the present case, round the nodular 

 enlargements. In Triticella they are scattered singly along 

 tlie stolon. It may indeed be a question whether this differ- 

 ence is of sufficient significance to warrant the separation of 

 forms otherwise so closely allied; but if the genus //«}>^wrarj'a 

 is retained the present form must be referred to it. 



The Lagenella nutans of Joliet obtained at Hoscoff is 



