582 



TAKU KOMAI : 



remarkably in the transverse direction, while the inner half of pharynx 

 {pk') has done so in the sagittal direction. Yellowish and brownish 

 pigment spots (pg) have appeared in the neighbourhood of the mouth, 

 the sensory capsule and the tentacular apparatus. Besides, a quantity 

 of dark spots now exists in the deeper tissues of the entire body, which 

 fact makes difficult the inspection of the inner organization. 



Fig 4 



Fig. 4. The cydippid larva, ready to hitch out, seen on the transverse plane, x 170. 

 o. Mouth aperture. pg- Pigment spots. 



4 pp. Polar plates. J. Aboral sense-organ. 



/. Tentacle-stem. t.sh. Tentacle-sheath. 



a. Oesophagus. fW. Inner part of pharynx. 



Fig. 4 represents the fully developed cydippid larva ready to hatch 

 out. Such a larva is frequently observed to do stretching movements 

 in the egg membrane and to press the mouth region against the latter 

 as if in attempts to free itself. Eventually, the membrane ruptures and 

 the larva escapes. For a short while after hatching in a vessel, the 

 larva swims about very actively by means of the combs, sinking now 

 and then to the bottom and adhering there by the inner surface of the 

 inferior part of pharynx, which surface is turned outwards by excessively 

 widely opening the mouth. Four or five hours* after hatching, the larva 



* The time required for the development varies considerably with temperature. 



