DIONIDE RICHARDSONI. 5 



Genus AMPYX, Dalman. 

 Ampyx macconochiei, Etheridge, juu., and Xicliolson. 



1903. Tritiucleus ? macconochiei, Keed, Lower Palseozoic Trilobites of Girvau (Palseont. See), 

 pt. i, p. 11. 



Another specimen of this imperfectly known form, with the head better 

 preserved in some respects than in the previous examples, has been obtained at 

 Balclatchie, and it necessitates a few corrections and additions to the earlier 

 descriptions. The glabella is more globular than pyriform in shape, thus 

 resembling Ampyx glohifrons, Olin,^ of the IVi72«cZe«s-Shales of Scania, and has a 

 very narrow, depressed ring-like neck at the base, and outside the pair of pit-like 

 depressions here situated, are seen a pair of small nodular lobes wedged in between 

 the cheeks and the ring-like neck. These nodular lobes have not been observed 

 in the other imperfect specimens. The cheeks are less elevated than the glabella, 

 but arch down rather suddenly at the sides, and there are also distinctly traceable 

 long slender genal spines curving gently backwards and reaching at least as far 

 as the pygidiura. There is certainly no trace of a fringe in this specimen, thus 

 confirming the evidence of the others ; and from the characters of the head-shield 

 we must now move back this species into the genus Ampyx, in wdnch Etheridge 

 and Nicholson doubtfully placed it. The ornamentation of the head-shield and the 

 characters of the thorax have been previously described. In the case of the pygi- 

 dium there seem to be rather more numerous rings on the axis, for eight or nine can 

 be counted, though only the first five or six are distinct, and the strong narrow 

 raised radiating ribs on the flat lateral lobes correspond to the first four rings. 

 The axis itself measures only about one-fifth the width of the pygidium, and the 

 edge of the pygidium is slightly raised into a narrow rim. The pygidial 

 characters suggest Ampijx rather than Triiincleus, and thus support the testimony 

 of the head-shield. 



Gem(s DIONIDE, Barrande. 

 Dionide richardsoni, Reed. Plate I, fig, 3. 



1903. Dionide richardsonii, Keed, op. cit., pt. i, j). 26, pi. iv, figs. 3 — 8. 



One good example of a complete individual has been obtained from the White- 

 house Beds of Shalloch Mill, a locality not previously known for it; and the 

 specimen deserves mention because it beautifully shows on the cheeks fine reticu- 



^ Oliu, " Chasmopskalk. o. Trinucleusskifferu i Skane," ' Medd. f . Lunds Geol. Fiiltklubb,' ser. B, 

 nr. 1, 1906, p. 71, pi. iv, fig. 13. 



