This scroll is attributed to Sugitani Rokkyo, a Nanga style painter, calligrapher and statesman. Some of his paintings are quite valuable. Comparing it to other of his work, the style is compatible but I haven't been able to verify the chop.

Sugitani Rokkyo was  Born in Kyoto to a Court nobleman and he served in the House of Peers for 30 years. He studied classical Chinese literature under Kusaba Senzan, Chinese poetry under Hayashi Sekikyo, Japanese-style painting under Ju Shunto, Japanese brush drawing under Kitamura Ryusho among others. Rokkyo is known as one of the most literate Japanese noblemen. He died in 1944 at the age of 80. One reviewer wrote, "His brush strokes are witty and vivant. The power of calligraphy floods out from the silk." . 

Whoever the artist, this is a finely painted scroll that is now showing it's age but it hasn't lost it's charm. The Japanese paint the most delightful crabs in all of art!