FOSSIL HYDROZOA. 



157 



points in which Labechia differs from Hydractinia are the apparent 

 absence of any apertures on the surface, and the fact that the former 

 does not grow in the form of crusts enveloping shells, but in the shape 

 of expansions attached to a foreign body at one point only. 



Two other fossil genera, viz., Palceocoryne and Corynoides, 

 have been referred to the Corynida, but in neither case is 

 the reference free from doubt. Palceocoryne (fig. 48) is a 

 minute organism which was discovered by Dr Martin Duncan 

 and Mr Jenkins growing attached to the margins of Lace- 

 corals (Fenestcllce) in the Carboniferous rocks of Scotland. 



Fig. 47. Labechia conferta, Edw. & H. A, A small specimen, of the natural size. B, A 

 piece of the upper surface of the same, enlarged, c, Portion of a vertical section under a 

 low microscopic power : a, The calcareous columns, represented as opaque ; b, The vesicular 

 tabulae, filled up with calcite. 



Its base is expanded, with finger -like processes of .attach- 

 ment. From 'the base rises a short robust stem, which is 

 marked with flutings and superficial granulations. The stem 

 terminates in a single polypite, the mouth of which is sur- 

 rounded by a single whorl of slender processes or " tentacles," 

 in the centre of which is the mouth. The entire polypary, 

 as above described, is " calcareous, dense, and ornamented." 

 In one living form only (viz., Bimeria, fig. 46, B), is the 

 polypary continued along the tentacles and upper part of 

 the body of the polypite, and in this case the polypary is 

 simply of the consistence of parchment. This peculiarity, 

 therefore, with the possession of a calcareous polypary, renders 

 the reference of Palceocoryne to the Corynida a matter of 

 question. According to the views of Prof. Young and Mr 



