696 MESSES. P. MAETIN DUNCAN AND H. M. JENKINS ON PALJEOCOEYNE. 
Bimerio vestita (Wright) was found on the Bimer Bock on the west coast of Ireland, 
and its organs of nutrition and generation have been examined by its discoverer and 
Dr. Allman*. 
In its early period of trophosome it is a simple or solitary hydrozoon ; but during 
growth it becomes compound, and every succeeding branch is terminated by a tentacu- 
late polypite. 
The gonosome of the fossil organism may be traced in a stout projection from the 
junction of the stem with the body in one specimen f, and possibly in the presence of 
some circular depressions on the under surface of the tentacular processes in others. 
As yet our material is not sufficient to enable us to decide upon the nature of the 
gonosome. 
The presence of the spinose ornamentation and the compact nature of the periderm 
of the new form distinguish it from all other Hydrozoa. It is probable that, like Bimerici 
vestita , the tentacular processes of the fossil form had ciliated ends projecting beyond 
the periderm, and that the metastome projected at certain times and not invariably. 
The zoological position of the fossil is amongst the Hydrozoa in the Order Tubula- 
ridae and near the Eudendridse. 
IV. Terminology . — Being satisfied that the fossil should be admitted amongst the 
Hydrozoa, its anatomical structures must assume the following names. The dactylose 
base is the hydrorhiza, the stem is the hydrocaulus, the tentacular body with the broad 
upper surface, with or without an evident metastome, is the polypite. The ornamented 
hard external tissue is the periderm or polypary. The faintly traced generative struc- 
tures constitute the gonosome, and the rest are embraced under the term trophosome. 
The term hydrosome refers to the whole. 
V. Classification . — 
Class Hydrozoa. 
Order Tubularidas. 
Family Pal^eocorynid^e. 
Genus Pal^eocoryne. 
Family Pal^eocorynid^e. — Hydrozoa, whose hydrosoma is fixed by a hydrorhiza. 
Polypary organized, calcareous, dense and ornamented, investing the whole of the Hydro- 
zoon, except the opening for the mouth and probably the terminations of the tentacles. 
Tentacular processes long, and more or less spined. 
Genus P al/eocoryne, gen. nov. 
Trophosome solitary. Tentacles few in number, long, in one verticel and ornamented. 
Hydrocaulus shorter than the tentacles, straight, cylindrical, broad and rigid, its 
ornamentation definite. Polypite either flat on the oral aspect, or elevated more or less 
* T. Sxrethill Weight, M.D., Edin. New. Phil. Journ. vol. x. N. S. 859, p. 105. Allman, Ann. Mag; 
Nat. Hist. S. 3. No. 77, p. 355 (1864). 
t Plate LXYI. fig. 11. 
