274 Prof. F. M'Coy on some new genera 



glass- like fibres exposed*. The analogy between those seems to 

 me very strong, and I know of nothing else in nature like the 

 fossil. I have named the genus from TruptT?/?, silew, and vrj/jua, 

 filum. Lest the specimen might be supposed to resemble a bun- 

 dle of certain Serpulce, I may mention that the rods of silica are 

 not tubes, and have no walls. 



Stromhodes Wenlockensis (M'Coy). 



Sp. Char. Corallum forming large irregular masses of polygonal 

 stems, the mouths of which vary usually from 8 to 10 lines in 

 diameter; boundary-walls strong, prominent, vertically sulcated 

 on the inside ; star depressed round the margin of the walls, 

 forming a large circular convexity nearer the centre, within 

 which is a concavity, from which rises the thick prominent 

 compound axis ; radiating lamellae twenty-four to twenty-nine, 

 strongest and most prominent on the circular convexity of the 

 star, where an equal number of small alternate ones disappear : 

 vertical section shows the thick central axis composed of irre- 

 gularly twisted plates, inner area a little narrower than the 

 outer area, from which it is separated by a solid vertical wall, 

 crossed by loose vesicular structure curving upwards and out- 

 wards, one or rarely two vesicular plates reaching across the 

 area on each side, vesicular plates of the outer area more curved, 

 slightly smaller, the rows inclining slightly upward and out- 

 ward, scarcely three cells in a row. A star 9 lines in diameter 

 has the prominent circular portion 7 lines in diameter, and the 

 prominent axis rather more than 1 line in diameter. 



To judge from the figure in the ' Silurian System,' that marked 

 t. 16. f. 8 a (not the 8 b), of Mr. Lonsdale's Acervularia Baltica 

 (Schw.), would seem to belong to this species, but according to 

 Phillips that has far more than thirty-six lamellae (Pal. Foss.) ; 

 the species represented by the latter figure has neither axis nor 

 divisional walls to the stars, and is certainly generically distinct 

 from Stromhodes ; the true A. Baltica of Schweigger, according 

 to his reference to the 'Amoenitates Academicse,' has no axis 

 and cannot belong to the present genus, of which this species is 

 the only one I am acquainted with in Silurian strata. The frac- 

 ture as usual passes through, and not between the columns, and 

 the buds are developed in the corners of the old stars. 



Not uncommon in the Wenlock limestone near Wenlock. 



* I believe M. Edwards considers this recent form to belong to the 

 Amorphozoa, and that the observed polypes were parasites. From the axis 

 of Antipathes being siliceous, I adopt for the present Mr. Gray's opinion. 



