種数 is read as しゅすう (shusuu) and means genus.
しゅすう
shusuu
すうしゅ
several varieties
くさぐさ
various
しゅもく
item
しゅるい
counter for kinds, species, etc.
たね
paternal blood
しゅぞく
stellar population (i.e. population I, II and III)
しゅし
seed
しゅべつ
classification
たねつけ
mating
たねうま
studhorse
しゅぶんか
speciation
たねほん
source book