210 PKOF. BEYNOLDS AND ME. VAUGHAN ON THE [May 1904, 



Teleostomi. 



SauricJithys acuminatus, Ag. — The teeth to which this name 

 is commonly applied occur in very large numbers, and are, with the 

 exception of those of Acrodus minimus, the most plentiful fossils 

 met with. Dr. Smith Woodward ! remarks on the close relationship 

 between the imperfectly-known genus SauricJithys and the better- 

 known genus Belonorhynchus, and tentatively suggests that the two 

 may really belong to the same genus. Mr. Montagu Browne, 2 on 

 the other hand, suggests that Saurichthys is ' a non-existent piscine 

 genus,' and that the teeth referred to under this name can be 

 assigned to labyriuthodonts, Phsiosauras, Hybodus, Gyrolepis, and 

 perhaps Colobodus. The Sodbury material consists entirely of 

 isolated teeth, and affords no assistance in the settlement of this 

 question. 



Sargodon toniicus, Plien. — Small teeth with long roots and some- 

 what chisel-shaped crowns, described under the above name by 

 Plieninger, 3 occur somewhat sparingly, as they do at Aust and 

 many other Rhaetic localities in the Bristol district. With them 

 are found teeth which differ from them only in having knob-like 

 instead of chisel-shaped crowns, and have been described under the 

 name of Psammodus orbicularis by Meyer & Plieninger and under 

 that of Sphcerodus minimus \>y Agassiz. Plieninger suggested, and 

 the suggestion is supported by Dr. Smith Woodward, 4 that these 

 belong to the same animal as the typical chisel-shaped teeth. 

 Mr. Montagu Browne 5 suggests that the knob-like teeth are to be 

 referred to Colobodus maximus (Quenstedt). 



GyroUpis Albertii, Ag. — The small striated scales of Gyrolepis 

 are very common. They vary a good deal in size and in the state 

 of preservation, some being much rubbed. Agassiz recognized 

 several species, based on the form of the scales ; but Dames 6 

 showed that probably the form of the scale varied in different 

 parts of the animal's body, and that the three forms of scale 

 described by Agassiz may all belong to one and the same fish. 

 This view is accepted by Dr. Smith Woodward. 7 



Notes on the Position of the Bone-Bed. 



Although the extreme variability of the Rhaetic Bone-Bed or 

 Beds in number, position, and development is well known, it may 

 perhaps be worth while to summarize its (or their) distribution in 

 the Bristol district. The typical position of the Bone-Bed 

 may be said to be at the base of the Black-Shale 



1 Ann. & Mag. Nat. Hist. ser. 6, vol. iii (1889) p. 302. 



2 Rep. Brit. Assoc. 1894 (Oxford) p. 657. 



3 Jahresh. Ver. vaterl. Naturk. Wiirtt. vol. iii (1847) p. 165. 



4 Catal. Foss. Fishes Brit, Mus. pt. iii (1895) p. 67. 

 * Rep. Brit. Assoc. 1891 (Cardiff) p. 645. 



6 Palseont. Abhandl. vol. iv (1888) p. 148. 



7 Trans. Leicester Lit. & Phil. Soc. n. s. vol. i, pt. xi (1889) p. 20, and Catal. 

 Foss. Fishes Brit. Mus. pt. ii (1891) p. 510. 



