NOTES AND EXHIBITS. 413 



this time Pleurodictyum lias not been recorded from N.S.W., and 

 the only species recorded from Australia is that mentioned by- 

 Prof. McCoy (1) ; and 1 am able to support his contention that it 

 occurs in Silurian formations in Australia. The specimen now 

 exhibited has cells over half an inch in diameter, and the whole 

 specimen measures two inches across. The period of time during 

 which Pleurodictytim flourished in the Bowning area was relatively 

 a short one, the total thickness of the stratum in which it 

 oocurs being only a few feet. T have not seen P. megastoma, but 

 I am aware that beds similar to the Bowning beds occur in 

 Victoria: it is, therefore, likely that the specimen under notice 

 may be identical with that species, (b) Calymene Blumenbachii : 

 this fossil also makes its appearance towards the close of the 

 series, and the species flourished during a relatively short period, 

 as it is found in a stratum about one foot thick. There appears 

 to have been a remarkably sudden invasion on the part of 

 numerous individuals of this species, followed by as sudden a 

 retreat. Immediately below the stratum from which this specimen 

 was obtained, Pliacops fecundus (?), the two species of Acidasjns 

 referred to above, and a species of Proetus are found. On the 

 invasion of C. Blumenhacliii these species, from some cause not 

 evident except the presence of C. Blumenbachii, altogether 

 disappeared, (c) Stipjyosed Fish-Sjnnes: these are usually found in 

 pairs and mostly in the same relative position to each other, 

 lying side by side but separated at their bases by distances 

 varying from 3 to 9 lines, and gradually approaching to contact 

 at their apices, which taper to very fine points. They have a 

 slight curve throughout which increases towards the apical points, 

 and their greatest diameter is near the middle. The pair exhibited 

 are four inches in length, and their greatest diameter is one line, but 

 they are incomplete. They are found associated with Acidaspis Leon- 

 hardi(?), Acidaspiss^). C?), Phaco^^s fecimdus (?), and P. caudatus, 



(1) Annals and Magazine of Nat. Hist. 1867, Vol. XX. p. 201, in a foot- 

 note as follows: — "It is worthy of remark that, as on the continent of 

 Europe the Devonian genus Pleurodictyum has now been found in Silurian 

 strata, so in these beds in Victoria, I find a new species (P. me<]astoma, 

 McCoy) with cells half an inch in diameter." 



