Sir P. Egerton on Fossil Fishes from Southern India. 95 



Lamna complanata, Eg. — The occurrence of a small lateral cusp in some of the 

 specimens of this species marks it as belonging to the genus Lamna, 

 although in other respects it would more properly be considered as 

 an Oxyrhina. Its nearest analogies are with Oxyrhina xiphodon and 

 hastalis. It differs from the former in having the outer surface more 

 prominent, and the inner one more evenly rounded without the flat- 

 tened character of the basal portion of the enamel. From the latter it differs in 

 the less prominent contour of the inner surface. It is distinguished from both by 

 the presence of the lateral cusp, in being infinitely smaller, and in its slender and 

 elegant proportions. The transverse section shows the antero-posterior diameter 

 to be exceedingly narrow — more so, indeed, than in any other species of the genus. 



Lamna sigmoides. — It is difficult in a mere verbal description to make intelligible 

 the minute distinctions which, in considering the characters of the 

 fossil Squaloid teeth, are the elements on which the species are elimi- 

 nated. A single tooth sent home by Mr. Cunliffe recals at first sight 

 the well-known Lamna acuminata of the British chalk. It approaches 

 also that species in size, being one of the largest of the Indian speci- 

 mens, which, generally speaking, are of unusually small dimensions. 

 In form it is intermediate between L. acuminata and L. cuspidata. It differs, how- 

 ever, from both in the sigmoid flexure of the cutting edge. There are no lateral 

 cusps visible. In front it varies from the form of L. cuspidata in the greater breadth 

 of the apex, and from L. acuminata in the parallehsm of the sides in the middle 

 region of the tooth. The outer surface is flattened until near the point, where it 

 is slightly rounded. The inner surface is convex and prominent. Seen in profile, 

 the cutting edge conceals the back of the tooth for two-thirds of its length ; it then 

 verges inwards until near the point where it again tends slightly outwards. The 

 base is partially concealed by the matrix ; but it appears to have been furcate, and 

 of rather small size. 



Odontaspis constrictus, Eg. — A very large proportion of the Indian Odontolites 

 belong to the species now under consideration. Out of some dozen 

 of specimens, I have not, however, found one having the base sufii- |j ^ 

 ciently perfect to show whether it supported lateral cusps or not. If 

 they were present, they must have been of very small size. Under this 

 imcertainty it is impossible to determine whether this species should be placed 

 under the genus Lamna or Odontaspis ; but I am inclined, from the slender 

 subulate aspect of the teeth, to refer it to the latter. At the time of writmg this, 

 I have not been able to compare the Indian specimens with figures of 0. gra- 

 cilis from the chalk and 0. suhulata from the lower greensand of Neufchatel ; but 

 the descriptions given of these species lead me to infer a considerable resemblance 



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