554 Bulletin American Museum of Natural History [Vol. LXVI 



dental trough has expanded so as to mask completely the germinal 

 wrapper from behind. Whether this is a geographical or an individual 

 variation cannot be determined without additional material from the 

 region. 



The tooth rows reach farther forward in old age than in youth, but 

 those of inunguis, unlike the other species, never closely approach the 

 mandibular symphysis. 



The Hyoid Arch 

 The hyoid bones of the Congo specimen closely resemble those of 

 similar aged material from Florida, and it is believed that no characters 

 for diagnosing the species are to be found in this structure. 



THE DISTRIBUTION OF TRICHECHUS IN THE AFRICAN REGION 

 As far as I have been able to ascertain, all specimens of African 

 manatees in museums are from the rivers or coastal lagoons of the West 

 Coast between Senegal and the Quanza, and all of these specimens are 

 from regions below the first rapids. However, it is certain that such 

 specimens as are on record do not completely represent the distribution 

 of the manatees in Africa, just as it is certain that all published records 

 of their supposed distribution are unreliable. The waters from which 

 the manatees have been reported with certainty or probability of 

 correctness are the following: 



Senegal 

 The African manatee does not seem to occur north of the Senegal 

 coast. Its presence there is established by the following records: 



1757. — Adanson (p. 143) mentions the capture of manatees in the marigot (lagoon) 

 de Kantai in December and January. 



1765. — Buffon (p. 390) notes the skull of a young specimen given by Adanson. 



1793. — Pennant (II, p. 296) records the presence of a specimen in the Leverian 

 Museum. 1 



1836. — A specimen was collected by Robert (p. 363) for the Paris Museum. 



1883. — Rochebrune (p. 190) states that the manatee was found in the marigots of 

 Lampsar, Leybar, and Bafing, and that Adanson mentioned their occurrence in the 

 marigot of Sorres, from which they have since disappeared. Rochebrune further 

 states that the manatee of the Senegal coast is not found in the rivers but in the 

 marigots. 



1886. — -Hartlaub (p. 15) records the presence of a manatee from Senegal in the 

 Vienna Museum. 



x The contents of the Leverian Museum were disposed of by auction in 1806. A copy of the sale 

 catalogue with the buyers' names added to some of the 7878 items is in the British Museum (Natural 

 History). An examination of this catalogue might reveal the present whereabouts of the specimen 

 named. 



