[111] The Anatomy of Invertebrated Animals, p. 519.

[112] Ussow states that they are independent.

[113] For a fuller account of this subject the reader is referred to the chapter on ‘The Development of the Eye.’

[114] Rabl holds that there is no contractile dorsal sinus, but that the appearance of contraction there is due to the contractions of the foot.

[115] I conclude this from Bobretzky’s figures.

[116] The following description applies specially to Loligo.

[117] In Loligo only a single pair of salivary glands is present.

CHAPTER X.

POLYZOA[118].