ON COLORATION IN FOSSIL SHELLS. 



289 



From an examination of a number of specimens exhibiting these 

 different patterns and their comparison with the colour-markings of 

 modern shells, there can be little doubt that they represent the 

 remains of original coloration. Dr. Wheelton Hind is followed in 

 regarding this species as belonging to Sijncyclonema (Mon. Pal. Soc, 

 "British Carboniferous Lamellibranchiata," 1903, p. 118, pi. xviii, 

 figs. 21-26). 



The specimen now figured is in the British Museum [30346]. 



Syncyclonema coloeata (Koninck). 

 Entolium coloratum, Koninck : Ann. Mus. Roy. Hist. Nat. Belgique, 

 vol. xi C1885), pt. 5, p. 241, pi. xxxii, fig. 21. 



Formation. — Bernician . 



Localiti). — Belgium. 



This specimen is a pectinoid valve bearing a series (about 18 rows) 

 of longitudinally arranged, zigzag patterns, which fit into one another, 

 but having equal spaces of separation. The actual surface structure 

 is quite smooth, and not ornamented with concentric striations. The 

 dimensions of the specimen are : length 33, height 44 mm. 



AvicuLOPECTEN RTiGTJLOSus (McCoy). PI. XXIV, Fig. 10. 

 Peden rugulosus. McCoy: "A Synopsis of the Characters of the 

 Carboniferous Limestone Fossils of Ireland," 1844, p. 98, 

 pi. xvii, fig. 7. 



Formation. — Bernician. 



Locality. — Kildare, Ireland. 



More than a dozen dark spots are observed on the umbonal half of 

 this (right) valve. They are of nearly equal size, covering mostly 

 about three ribs, and are rather more elongate than round. This 

 colour feature is extremely rare among Palaeozoic pectinoid shells, 

 and was very early noticed by Edward Forbes in connection with 

 a specimen he had examined in the Museum of Practical Geology, 

 Jermyn Street, referring to it as an unnamed species of Aviculopeden 

 showing "spotty markings on the ribs in the manner of many existing 

 Pedines'''' (Proc. Roy. Soc. London, vol. vii, 1854, p, 23). 



The specimen is in the British Museum [30,348]. 



Streblopteria sublobata (Phillips). PI. XXIV, Figs. 8, 9. 

 Avicula mhlohata, Phillips : Illustrations of the Geology of Yorkshire, 

 Mountain Limestone District, 1836, p. 211, pi. vi, fig. 25. 



Formation. — Bernician. 



Locality. — Derbyshire. 



The radiating brownish bands, representing the original colour- 

 markings so frequently seen on this shell, have been ably described by 

 Mr. R. Etheridge, jun. (Geol. Mag., 1876, p. 152, pi. vi, figs. 2-6), 

 who recognized considerable variation, one valve possessing as few as 

 six or seven, another showing fourteen or fifteen, and all passing from 

 the umbo to the margin in a straight course. They sometimes differ 

 in width, the central ones being broadest. Both bifurcation and 

 trifurcation exist in some examples, whilst a smaller band is 



VOL. VII. — JUNE, 1907. 20 



