(1688) are six transparent parts that hang outside , and of which there are three on either side of the head .These parts are alone the reason why I had the frog - worm drawn , for in each of these parts I was vastly fascinated to see very distinctly the circulation of the blood , which was forced from those parts which were These probably were the tiny olfactory clefts , which can give the impression of being eyes .The bilateral suction pad might also be considered eligible ; but it was evidently recognized as such by L .