84 VINE : BRITISH PALAEOZOIC CTENOSTOMATOUS POLYZOA. 
1. Genus x\scodicty2E, Nicholson & Etheridge. 
2. ,, Rhopalonaria, Ulrich. 
But previously to the publication of the " Report " a new genus was 
founded for the reception of some very peculiar and primitive types 
of Polyzoa, found both in British and American Silurian rocks. 
1890. Genus : Vlnella, E. 0. Ulrich, Cin. Soc. Nat. Hist., March, 
p. 173. 
Zoarium attached to foreign bodies, consisting of exceedingly 
slender ramifying thread-like tubes, occasionally arranged in a radial 
manner, surface of tubes often faintly-lined longitudinally ; a row 
of widely-separated small pores along the centre of the surface of the 
tubes. Zocecia unknown. 
Vlnella repens, Ulrich, pi. III., figs. 1-4. 
Zoarium repent, stolons thread-like or contorted, and where best 
preserved (see figs. 2-3) very small pores are arranged along the 
centre of the upper surface. 
Locality and Horizon : Upper Silurian, Buildwas Beds of Wen- 
lock Shales, Shropshire ; Lower Silurian, Cincinnati and Chester 
Groups, U.S. America (Ulrich) ; L T pper Silurian, Sweden (Lindstrom). 
This is the most primitive of all the Wenlock species, and one 
of the most abundant. The forms are generally found on broken 
shells, but occasionally on crinoid stems. All the examples figured 
are British, and are in my own cabinet. As yet, though several 
hundreds of examples have passed through my hands, none of them 
have been found in any of the washings above the Buildwas beds. It 
will be seen that no essential difference exists between the British 
and the American forms, so that the specific name V. repens will 
apply to examples derived from Lower and Upper Silurian rocks 
alike. I have already given my opinion respecting these delicate 
thread-like organisms, and unless the forms find a resting place 
amongst the Ctenostomata, a new sub-order must be created for the 
whole of the species that will be described in this paper. I have not 
the least doubt but that the organisms are really Polyzoan, and I do 
not fear the criticisms of fellow-workers on recent Ctenostomata 
whenever the stoloniferous portions of the same are microscopically 
