Simplify the following text for a Grade 10 native English-speaking person.
Original: The genus contains two species , the Indian Rhinoceros ( Rhinoceros unicornis ) and the Javan Rhinoceros ( Rhinoceros sondaicus ) .
Simplified: The genus Rhinoceros of the family Rhinocerotidae includes the one-horned rhinoceroses , of which there are two extant species : the Indian rhinoceros ( R. unicornis ) and the Javan rhinoceros ( R. sondaicus ) .