GIGANTOCYPR1S MtJLLERI 2II 



tures separate, and this accounts for the incorrect position which I gave to the f sclerite 

 in Doloria (193 1, p. 442, fig. 2). The function of this backward extension would appear 

 to be to give extra stability to the main support of the vibratory plate of the maxilla. 



Fig. 8. Reconstruction of front part of Gigantocypris from the level of the adductor tendon viewed from 

 behind to show the body retractor system and its relation to the endoskeletal system. The anterior hypostomal 

 apodemes lie in the plane of the paper. The antenno-labral apodemes which are at right angles to the latter 

 are thus mainly hidden by the adductor tendon. The setal armature of the mouthparts has been omitted. 

 a. 1 , antennule ; a. 2, antenna ; a.h.a. anterior hypostomal apodeme ; a. La. antenno-labral apodeme ; a.t. adductor 

 tendon ; gn. gnathobase of mandible; lab. labrum; m. mouth; m.add. adductor muscle; mdb. mandible; 

 m.dv.b.r. dorso-ventral body retractor muscle; n.e. nauplius eye; oes. oesophagus \p.e. paired eyc;st. stomach. 



The caudal furca has its own system of sclerites which, as I have already mentioned, 

 are quite separate from the rest of the skeleton. The muscles attached to the caudal 

 furca which give it stability are the dorsal longitudinal series which attach directly to 

 the shell at the side of the heart (Fig. 9) and a powerful pair of muscles which run for- 

 wards, and after attaching to the thin body wall between the caudal furca and the hinder 

 margin of the first trunk limb, continue forwards as a group of three muscles on either 

 side, to attach to the adductor tendon and to the apodeme between maxillule and maxilla 

 (Fig. 6). 



4-2 



