Squid, also known as cuttlefish, will use "inkjet" as an escape method when encountering a strong enemy and wait for an opportunity to leave, so it has the names of "squid" and "cuttlefish". China is divided into three genera under the sepiidae, namely, Sepiella, Sepiella and Sepiella. A marine cephalopod mollusk of the order Squid, closely related to octopus and squid.
morphological character
The body can be divided into three parts: the head, the feet and the trunk. The trunk is equivalent to the visceral mass, which is covered by a muscular sheath and has a calcareous inner shell. Head: the front end of the body is spherical, with a mouth at its top, an oral membrane around it and five pairs of wrists around it. There are a pair of developed eyes on both sides of the head, and the structure is complex. There is an oval pit under the back of the eye, called olfactory trap, which is the olfactory organ, equivalent to osphradium of Gastropoda, and is a chemoreceptor.
Foot: it has been specialized into wrist and funnel. Wrist 10, symmetrically arranged left and right, with the first pair in the center of the back and 215 pairs to the ventral side in turn, in which the fourth pair of wrists is particularly long, and its end is tongue-shaped, which is called tentacular arm. It can prey and contract into the wrist capsule.
There are four rows of sucker with handle on the inner side of each wrist, and there are only 10 rows of small sucker on the inner side of the tongue at the end of the wrist, which is called wrist-touching spike. On the ventral side of the head, the base of the funnel is wide and hidden in the cavity of the jacket, and there are oval cartilage depressions on both sides of its ventral surface called atresia grooves.