384 PROCEEDINGS OF SECTION C. 



tubes in G. conferta measure about .017 mm. in diameter ; the pellets 

 are often as much as 3 mm. in length. This species also occurs in the 

 Wenlock limestone of Dudley, England (o) (pi. III., fig. 2). 



The third Victorian form noticed is in all probabiUty referable to 

 G. pisoUtica, Wethered.(p) A detailed description of this larger-tubed 

 form as it occurs in the Victorian limestones has already been given 

 (see ante, p. 382). 



In a thin slice of the Lower Cambrian limestone of AJrdrossan, 

 South Australia, for which I am indebted to Mr. Douglas Mawson, B.E., 

 there is a form of GirvaneUa without doubt referable to G. 'prohlematica{q), 

 as shown by its loosely aggregated and contorted tubules. The diameter 

 of these tubes (about l-500in.) is, however, only half that of the 

 typical species from Girvan. There is so much variation in the size 

 of the tubules, even in the same limestone specimens, as originally 

 recorded by Nicholson and Etheridge, that this slenderness is not of 

 primary importance. 



SUMMARY AND CONCLUSIONS. 



1. The tubular organisms included under the name of GirvaneUa 

 which have already been recorded from other countries in strata of 

 Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Jurassic 

 ages, as well as in the L. Cambrian of South Australia and the Car- 

 boniferous of Queensland and New South Wales, occur as important 

 rock-formers in the limestones of Victoria, of Silurian (Yeringian) age. 



2. There appear to be at least three forms of the genus present in 

 the Victorian limestones, viz., G. conferta, Chapman. ; G. cj. 

 Wetheredii, Chapm. (= G. incrustans, Wethered, non Bornemann) ; 

 and G.{'i)pi$oUt,ica, Wethered. 



3. The genus GirvaneUa, which has been variously assigned to 

 the foraminifera, sponges, stromatoporoids, and calcareous or encrusted 

 algse, is here shown to have no claim to be regarded as one of the forami- 

 nifera, but to have strong affinity with the algee, and especially with 

 the CyanophjcecB or blue-green algae. 



BIBLIOGRAPHY. 



Bornemann, J. G. — " Die Versteinerungen des Cambrischen 

 Schistens-systems der Insel Sardinien." Nova Acta Ac. Caes. Leop. 

 Car., vol. U., 1887. 



Brady, H. B.^" Report on the Scientific Results of the Voyage 

 of H.M.S. Challenger. The Foraminifera." 7yOology, vol. ix., 1884, 



Brown, A. — "On the Structure and Affinities of the Genus Soleno- 

 fora, together with Descriptions of New Species. " — G&)1. Mag., 

 Dec. IV.. vol. I., 1894, p. 203. 



(o) Examples in the author's collections. 

 (p) Wethered ('89), p. 200, pi. vi., figs. 8, 10, 11. Also ('90) pi. xi., fig. 3. 

 (q) The GirvaneUa figured by Etheridge irom S. Australia appears to resemble 

 more closely the form described by Bornemann from the Cambrian of Sardinia 

 (cf. Etheridge, jun., '90). 



