18+ Kagakuteki ni Sonzai shiuru Creature Musume no Kansatsu Nisshi

Whether they're part cat, part horse, or part spider, Daisuke has always been fascinated with the uniquely exotic beauty of monster girls. When he finds himself whisked away to a fantastic world full of all manner of demihuman life, he swiftly gets to work meeting (and analyzing!) as many as he can. There's really only one logical thing for this stranded scientist to do: he's going to become the creature girl harem king!!

(Source: Seven Seas Entertainment)