BAIRDIA. 17 



B.fusca, G. S. Brady, 'Trans. Zool. Soc' vol. v, p. 364, pi. lvii, fig. 9 (from 

 Australia) ; and the fine species from the London Clay (' Monogr.,' p. 52, pi. vi, 

 figs. 1 and 2), though like Brady's B.formosa ('Ann. Mag. Nat. Hist.,' ser. 4, 

 vol. hi, p. 221, pi. 14, figs. 5 — 7, from Tenedos), is probably B. subtrigona, 

 Bornemann (' Zeitschr. deutsch. geol. Ges,,' vol. vii, p. 357, pi. xx, fig. 4), from the 

 Oligocene Septarium-clay of Hermsdorf. 



We have now seen from the Belosepia-bed of Bracklesham (British Museum) a 

 very fine example of the real B. subdeltoidea, which we have compared with 

 authentic specimens (from Osnabriick) sent by Count Minister to London many 

 years ago. 



2. The very small Bairdia ('Monogr.,' loc. cit., fig. 3), from the Red Crag is 

 difficult of determination. 



3. With the Bracklesham specimen is a smaller individual, relatively thicker and 

 rounder ; it may belong to a different species, but for the present we leave it 

 as a probable variety. 



4. Bairdia subtrigona, Bornemann. 



Bateuia subtrigona, Bornemann. Zeitschr. d. g. Ges., vol. vii, 1855, p. 357, 



pi. xx, fig. 4. 

 subdeltoidea, Jones. Monogr. Tert. Entom., 1857, p. 52, pi. vi, figs. 



1,2. 

 subtrigona, Bornemann. Jones, Geol. Mag., 1870, pp. 157, 159 ; 1887, p. 



387, pi. xi, fig. 1. 



This specimen from the London Clay (British Museum) is referred to above 

 in our note on B. subdeltoidea, as belonging to Bornemann's B. subtrigona. 



5 and 6. Bairdia pdsca, Brady (see above) ; and Bairdia contracta, Jones. 

 These follow next in order. (British Museum.) 



7. Bairdia Londinensis, Jones Sf Sherborn. Plate II, figs. 18 a, b. 



Bairdia Londinensis, Jones & Sherborn. Geol. Mag., 1887, p. 387, pi. xi, fig. 2. 



This is a small neat Bairdia, of a not unusual form, but not exactly matching 

 in shape any species known to us ; it is, moreover, denticulated at the end margins, 

 and punctate all over with very distinct, roundish, close-set pits. This valve is 

 stained with numerous bright-orange irony spots, which possibly may be due to 

 traces of the original colouring of the shell. 



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