532 BULLETIN 58, UNITED STATES NATIONAL MUSEUM. 



The callosities appear to develop rather late and only to a slight 

 degree, as they are not even indicated on the hyo-hyp(^plastra of 

 the young, while in equally large specimens of other species they 

 have already reached a considerable size. 



Habitat. — Known with certainty only from the Malay peninsula 

 and archipelago. As for its alleged occurrence within our terri- 

 tory see remarks on p. 530. 



