270 ADOLF H. SCHULTZ 



to be recognizable in adults. The constriction of different por- 

 tions of the frontal arm of the great fontanelle results from locally 

 decreased or increased growth of the lines of ossification, and 

 may occur in any situation, but appears to be most common 

 between the two tubera frontalia. Double constriction to form 

 secondary fontanelles has also been described (Rauber '06). 

 This identity of the metopic and the great fontanelle is also 

 demonstrated by the position of the fontanelle bones, which occur 

 anywhere from the bregma to the upper portion of the nasal 

 third of the frontal arc (Hartmann 1869, Barclay-Smith '09 and 

 '10, GulUver 1890). Whether the above described case of partial 

 persistence of the metopic fontanelle in an adult was associated 

 with a fontanelle bone can not be determined with certainty, but 

 seems probable, especially upon examining the inner surface. 



Before any definite statements can be made as to the cause of 

 the occurrence and partial persistence of a long frontal arm of 

 the great fontanelle, more material must be available, and at- 

 tention must be paid to correlations, especially in the frontal 

 region. The author hopes by this contribution to stimulate 

 interest in this anomaly in order that further cases may be re- 

 ported. Observations on the occurrence of fontanelle structures 

 in the frontal bones of mammals have been reported in a limited 

 number, and further cases would be of great value. Among 10 

 skulls of erethizon dorsatus, which the author collected recently, 

 3 cases presented paired symmetrical fontanelle bones extending 

 far between the frontalia. Figure 5 shows one of these cases. 



