248 MORPHOLOGY OF INVERTEBRATE TYPES 



to the horseshoe organ of the female. The spermatophores 

 have the shape of an elongated tube with double walls and an 

 ejaculatory apparatus at the rear end. The space between 

 the thin inner wall surrounding the sperm rope and the thick, 

 chitinous outer wall is filled with a liquid. At the front end 

 of the sperm rope is a sticky plug. The ejaculatory apparatus 

 consists of a flask-shaped sac prolonged into a long filament 

 which is partly inclosed in the case and partly free. The proxi- 

 mal portion of the filament is somewhat thicker than the rest and 

 is provided with a spiral thickening of its wall, called the spring. 

 The female reproductive organs consist of an ovary, oviduct, 

 a pair of nidamental glands and a pair of accessory nidamental 

 glands. The ovary is a large organ situated in the ccelome. 

 The eggs drop into the ccelome and pass into the oviduct through 

 the ciliated funnel of the latter. The oviduct consists of three 

 portions. The first portion is a tube at first running forward, 

 then backward and then again forward. The second portion 

 is considerably thicker and glandular in its structure. It is 

 usually called the oviducal gland and produces spherical capsules 

 of the individual eggs. The last portion is comparatively short 

 and opens into the mantle cavity on the left side of the body 

 near the anus. The nidamental glands are situated on the lower 

 surface of the viscera. They are large, rounded bodies lying side 

 by side in the median line of the trunk and opening into the 

 mantle cavity. The nidamental glands produce the substance 

 of which the capsules of the egg masses are formed. In front 

 of the nidamental glands are the two accessory nidamental glands, 

 smaller in size and oval. Their function is not known. 



Instructions 



i. Place a squid on its right side, head towards you, in a large 

 dissecting tray with water. Make a full page drawing of the 

 left side. Label : head, first, second, third and fourth arms, ten- 

 tacles, eye, aquiferous pore, funnel and mantle. In the eye label: 

 iris, pupil and lens; in the mantle: its free edge or collar, with its 



