DuERDEN — On some neiv and rare Irish Polyzoa. 135 



Group.— ENTOPROCTA, Mtsche. 



Family. — PEDicELLi^'iDiK, Hincks. 



Genus. — Baeentsia, Hincks. 



Barentsia nodosa, Lomas. PI. Y., fig. 4. 



Pedicellina gracilis^ var. nodosa. Panna of Liverpool Bay, vol. i., 

 3). 190, pi. iii., fig. 3. 



Ascopodaria nodosa, Lomas, Proc. Liverpool Lit. and Phil. Soc, 

 1886, vol. xli., p. 46. 



The history of this species is interesting. Mr. Hincks, in his 

 description of Pedicellina gracilis, Sars, Brit. Mar. Polyz., p. 570, 

 mentions, that occasionally the slender portion of the peduncle is veiy 

 much elongated, and consists of several sections separated by knots or 

 swellings, which are muscular in character like the larger basal swell- 

 ing. Mr. Lomas, in the ''Pirst Eeport upon the Pauna of Liverpool 

 Bay," figures this form, and makes of it a new variety under the name 

 of Pedicellina gracilis, var. nodosa. Purther consideration, however, 

 led him to place it in the genus Ascopodaria, founded by Busk. — 

 " Challenger " Eeport, vol. xvii., Polyzoa, p. 41. In 1886, Lomas 

 described it as Ascopodaria nodosa, in a Paper read before the Liverpool 

 Literary and Philosophical Society. It has been shown above, 

 however, that the generic term Barentsia has the claim of priority to 

 that of Ascopodaria. 



The important feature in the new genus is connected with 

 the stem. It is divided into a barrel-shaped expansion at the 

 base springing from the stolon, and a narrower, rigid, distal portion. 

 The basal cylinder and parts adjoining are filled with muscular tissue, 

 which stains deeply and works the other portion, while the other con- 

 necting parts of the chitinous peduncle are lined with a delicate 

 parenchymatous tissue. 



In Barentsia nodosa the most striking feature is regarded by 

 Lomas as a second muscular swelling or node in the middle of the 

 stem above the basal cylinder ; while there is a third and smaller one 

 under the head. 



In material which I collected from Killiney Bay, in January, 1891, 

 I came across this species growing on sea-weed, and I have since had 

 my identification kindly confirmed by Mr. Lomas. In my specimens, 

 several of the forms have two muscular swellings in addition to those 



