175 
Spirifera [Martinia) perplexa, 0. A. Derby, 1874, Bull. Cornell Dniv. (Sci.), I, No. 2, 
p. 16, pi. 3, fig. 27, 39, 40, 45, 50, and pi. 8, fig. 13. 
Spirifer lineatus, B. Toula, 1874, Sitz. K. Akad, Wissen., LXX, p. 5, pi. 1, fig. 2. 
,, ,, Idem, 1875, ibid., LXXT, p. 545, pi. 2, fig. 3. 
This shell is oval in contour, usually transverse, hut rarely longer 
than broad. Xhe hinge area is not well developed, and not easily seen on 
account of the strong curve of the beaks, which overhang it and approach 
each other closely at their extremities ; the deltoidal fissure is partly covered 
by a pseudo-deltidium. Among normally developed individuals the two valves 
are of nearly equal depth, and regularly curved ; when the ventral valve is 
sinuous, which is not often, the ventral furrow is broad and not well marked, 
and is apparent only by the sinuosity of the base. When the dorsal valve 
has a dorsal ridge this is also obscure, and never projects beyond the base. 
The external surface of both valves is ornamented with concentric lines of 
growth produced by thin imbricated lamellae, the development of which 
seems to be interrupted at rather short but regular distances, in order to give 
rise to some small spiniform expansions. It is not often that these expan- 
sions are preserved, although to them we must attribute the concentric rows 
of pits and longitudinal striae which have caused some varieties to be considered 
distinct species. Although the shells of this species have seldom preserved 
their spiral supports, they present no well-marked structural characteristic to 
distinguish them from, other SpirifereE, or to maintain them in the genus 
3Iartinia, which McCoy created for them. 
Dhnensions. — The largest Australian specimen sent me is thirty-six 
millimetres long and forty-three millimetres broad. 
Horizon and Localities . — This species is very widespread in the 
Carboniferous System, but is more abundant in the upper than in the lower 
beds. It is very common at Vise and in many localities in Yorkshire and 
Ireland. In New South Wales it was found in a greyish limestone at 
Buchan, and between the Kama Kiver and Dungog ; also in a brownish 
sandstone in the Muree Quarry, Baymond Terrace. 
