1934] Hatt, African Manatees 547 



skulls of Florida manatees examined range from 255 to 375 mm. in total 

 length, or from youth to full maturity. In these specimens there is a 

 great range of nasalia, from apparent total absence to well-developed peg- 

 shaped bones lying in deep sockets of the frontal and uniting in a loose 

 suture with the ascending rami of the maxillae, and (or) the premaxillae. 

 In length these vary from 20 to 48 mm. in adult specimens. Of two skulls 

 identical in size, one has large, long nasal bones, the other bears no 

 evidence that nasal bones have ever been present. 



A large manatee, reputedly from Texas, has nasalia thoroughly 

 typical of those from Florida. Four specimens from Guatemala present 

 extreme variation, two having peg-shaped bones, one with flat nasalia 

 horizontally placed and roofing the posterior part of the nasal trough, and 

 the fourth with its pair of nasalia flat and vertically placed as are 

 those in specimens of inunguis. A Puerto Rican manatee differs in no 

 respect from certain Florida specimens in regard to its nasalia. 



The skulls of inunguis examined ranged in greatest length from 200 

 to 360 mm., from early youth to maturity. Ten of these were cleaned, 

 three had been roughed out in such a way that the nasal bones, if present, 

 may have been lost in the field, and six were roughed out so that there 

 was very little possibility of the nasal bones having been lost. I cut away 

 the dried flesh of these six skulls in a search for nasal bones with the 

 following results: In two skulls, 265 and 330 mm., in greatest length, 

 there was no trace of nasalia, either actually, in pits for their reception, or 

 in grooved surfaces for articulation. Neither was there any indication 

 that nasals had fused to the frontal bones. In another specimen, 355 

 mm. long, there was no trace of a nasal unless a minute conical nodule (4 

 mm. long) lying in the site of a right nasal was a vestige of this bone. On 

 the right side of a fourth specimen, 270 mm. long, there was a well- 

 developed plate of very compact bone lying totally free, but closely asso- 

 ciated with the vertical surface of the frontal bone at the anterosuperior 

 border of the nasal chamber. There was no trace of a corresponding bone 

 on the opposite side. The two remaining skulls, 260 and 330 mm. long, 

 bore nasalia on each side similar to that mentioned. The five such nasalia 

 examined were alike in being of a modified lozenge-shape (triangular or 

 quadrangular), though their greatest diameters ranged from 25 to 13 

 mm., their minima from 15 to 11 mm., and their thicknesses from 3 to 6 

 mm. These bones lay with their long axes anteroposterior, and their 

 chief plane vertical. They were in loose contact with the median free 

 surface of the orbital branch of the frontal directly posterior and ventral 

 to the anterior median edge of the frontal. In one case the lateral 



