F. JR. Cowjjer Reed — Fossils fro)ii Girvan. 295 



weathered and the concavity of the cup is hidden by matrix. It 

 seems to be a new species, but the arrangement of the plates and 

 general characters ally it to R. occidentalism Salter,' of the Trenton and 

 Galena Limestones of North America, and to R. orhis, Eichw.," from 

 the Orthoceras Limestone of the Baltic regions. 



It cannot, however, be identified with either of these species, nor 

 with any other previously described from the British Isles, and though 

 its characters are somewhat imperfectly known a specific designation 

 seems necessary, and that of R. girvancnsis is suggested. 



Spongariwn ardinillanense, sp. nov. (PI. XII, Tigs. 7, 8.) 



Corallum subcircular, discoidal, or saucer-shaped, flattened, thin, 

 composed of small, contiguous, low, rounded, subequal ridges, radiating 

 to margin regularly and horizontally in one plane from small smooth 

 central area, and increasing in number by bifurcation at a little more 

 than half their length with a considerable amount of regularity (and 

 by less frequent intercalation) to the number of 100-110 on the 

 margin. Ridges crossed by 3-4 strong concentric wrinkles and by 

 numerous fine, regular, equidistant, closely-set, impressed lines. 

 Inferior, surface of corallum not visible. 



Dimensions. — Major diameter, 30 mm. ; minor ditto, 25 mm. ; 

 about twelve ridges to every 10 mm. round margin. 



Remarks. — The counterpart of this specimen has precisely the 

 same appearance, the disc or flattened saucer liaving been split 

 regularly in one plane. Probably the base was covered with a thin 

 epitheca, and it seems to have had a small central knob for attachment. 

 The substance of the corallum appears to have been of a black corneous 

 nature. 



This peculiar fossil may best be referred to the genus Spongarium, 

 the true affinities and zoological position of which are unknown. 

 The species which approaches it most closely is ^S^. cequistriatum, 

 McCoy,^ from the Upper Ludlow rocks ; the elliptical shape and 

 coarseness of the closely-set radiating ridges are features in common, 

 but in the bifurcation of the ridges in our species there is an obvious 

 difference. No British member of this genus appears to have been 

 recorded except from the Ludlow beds. Ours comes from the 

 Ealclatchie Group of Ardmillan. 



Annelidan Tube {'i). (PI. XII, Figs. 9, 10.) 



Body forming a regularly cylindrical (?), straight, jointed tube, com- 

 posed of a number (+ 15) of thin, calcareous, nearly flat rings of 

 regular and equal size, successively overlapping to a slight extent 

 those behind, and somewhat thickened towards the overlapping 

 (posterior) edge. Each ring has a length approximately equal to 

 one-third the diameter of the tube, and is marked by fine regular 

 longitudinal plications, causing a weak serration of the posterior edge ; 

 a very delicate longitudinal striation is also present. Length of rings, 

 1 •5-1 '6. Diameter of tube, about 5 mm. 



' Hinde, op. cit., p. 842, pi. xxxvii, figs. 3, Zn-m. 



2 Rauff, op. cit., pp. 654-691, t. iii, figs. 7-10 ; t. iv, figs. 1-6. 



3 McCoy : Brit. Pal. Foss. Woodw. Mus,, 1855, p. 42, pi. IB, figs. 15, loa. 



