Sentence:  4. P. californicum n. sp. / Very similar in color and sculpture to "seriatum". The form is, however, <WSD>sensibly</WSD> narrower, averaging very nearly two and one half times as long as wide, while in "seriatum" the length is ahout two and three- tenths times the width. 
Meaning of the word marked with <WSD> tags:  In a way that can be sensed or noticed; perceptibly.