the radiolarian fauna of the Jurassic and older rocks in Italy. Rare in diabase tuff from the River Badoengan.
The forms described by Prof. Parona as Stylosphfêi a lanccola , (Boll. Soc. geol. Italiana, vol. ix, p. 21, pl. i, figs. 18, 19) from the Jurassic rocks of Cittigho appear to me to be nearly ïelated to the present species. They are described as having only one medullary test, but the figures show a clear central space which appears to represent an inner shell. Should this prove to be the case the forms will co me into the same genus with the species described above.
Stylatractus ovatus sp. nov. Pl. IV, figs. 29, 31, 32, 33, 36.
The outer test is a short oval with a stout, gradually tapeiing spine at either end, the middle shell is regularly oval, it has large pores and is connected by numerous stout rays with the outer test; the central medullary test is nearly round, with minute pores, and it is joined to the middle shell by slender rays. In no specimen are the radial spines preserved intact; they appear to have tapered gradually and tenninated obtusely. The outer test measures 0.105 mm. by 0.085 mm., the middle 0.05 mm., by 0.045, and the central test is 0.025 mm. in diameter. Ihe longest spine preserved is 0.07 mm. in length.
As shown in the figures, this species appears under very different aspects in microscopie sections of the rock, and it was not until after renewed study and comparison of measurements, that these varied forms were recognized as belonging to one and the same species. In fig. 36, a vertical section is shown, but the centtal medullary test is wanting and the radial spines are incomplete; fig. 33 represents another vertical section in which both the central and middle shells can be seen, but only one radial spine remains; in fig. 32, likewise, there is but one incomplete spine remaining, and the middle test incloses and conceals the central shell; fig. 29 appears to be a direct transverse section of a specimen showing the outer and middle shells,