414 Dr. S. Woodward — On the Fossil Sirenia. 



ridged crowns, in all which points they resemble the Manatee more 

 than the Dngong. The anterior molars were deciduous. 



The pelvic bones are better developed than in existing Sirenians ; 

 there is also a rudimentary styliform femur. They were therefore 

 less specialized than their modern representatives (Flower). 



Fifteen species of fossil Sirenians have been referred to the genus 

 Halitherium (see list pp. 424-5), 



Only one species, Halitherium Canhami, Flower, from the Red. 

 Crag of Waldringfield, Suffolk, occurs fossil in England. (See 

 Quart. Journ. Geol. Soc. 1874, vol. xxx. pp. 1-7, pi. i.) 



This interesting species is represented by a coloured cast of the 

 skull in the British Museum (Natural History), the original being 

 preserved in the Ipswich Museum. 



Another genus, very considerably larger than Halitherium, has 

 been described by Professor Giovanni Capellini, from the Pliocene 

 of Eiosto, Bologna, under the name of Felsinotherium Forresiii ; it 

 consists of a nearly perfect skull and lower jaw, of which the 

 British Museum (Natural History) also possesses a coloured cast of 

 the type specimen. 



Felsinotherium closely resembles Halicore in its dentition : 



..11 , 5. 5. 



mcisors q — q molars ^ — ^ 



Another species of Felsinotherium, namely, F. Gervaisii, has also 

 been described by Prof. Capellini from the Pliocene of Siena.^ 



The skull and lower jaw of a very singular type of Sirenian, named 

 by Prof. Sir Eichard Owen Prorastomus sirenoides, has been obtained 

 from strata of Tertiary age in Jamaica, and is preserved in the 

 British Museum (Natural History). 



It differs widely from either known existing or extinct genera of 

 Sirenia, but probably approaches nearer to the living Manatus than 

 to Halicore. But it is in its dentition that Prorastomus presents the 

 most remarkable deviation from the rest of the order, for we have 

 present at one and the same time, clearly differentiated — 



incisors 7, — 7,, canine , — i, premolars ^ — ?, molars - — :r^48 teeth. ^ 



6 — 6 1 — 1 ■■■ O — 3 — 3 



Another curious discovery is that of a natural acst, found by Dr. 

 Grant of Cairo, in a block of Eocene (?) rock from the quarries of 

 Mokattam, near Cairo, which proved to be a most perfect copy of 

 the interior of the skull or brain-cavity of another species of Siren, 

 named Eotherium vFgyptiacum by Owen, who described it in the 

 Quarterl}'^ Journal Geol. Soc. for 1875 (vol. xxxi. p. 100). 

 Portions of the characteristic ribs and some detached teeth have also 

 been obtained from the same locality. This natural cast of the 

 brain of Fotherium is placed with the other fossil Sirenia in the 

 Geological Gallery of the British Museum (Natural History). 



Early in the present year, the Trustees acquired by purchase, 



1 See Mem. dell'Istit. di Bologna, ser. iii. torn. i. fasc. 4, pp. 605 — 634, tav, 

 i— vii. 



^ See Quart. Journ. Geol. Soc. 1855, vol. xi. pi. xv. figs. 1 — 6, and 1875, vol. 

 xxxi. pp. 559 — 567. 



