536 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVIII. 



In the body cavity is a fluid representing the blood which circulates 

 somewhat. On the dorsal surface close to the anterior margin is the 

 median eye and the first traces of the nerve ganglion. Both the eye 

 and the dorsal surface of the ganglion are well pigmented. This 

 ganglion represents practically only the future supra-oesophageal one 

 and the esophagus does not pass through it. The infra-oesophageal 

 portion of the ganglion (see p. 552) appears with the development of 

 the appendages. 



Fig. 36. — Newly hatched Natjplitjs of Caligus eapax, pigment of bright edst color. 



The anterior part of the bocly is transparent and through it can be 

 seen the muscles which move the appendages. They extend backward 

 obliquety on either side from the bases of the appendages to the 

 median line a little back of the center. They are faintty striated and 

 very well developed, furnishing powerful motors for swimming. 



The posterior portion of the bod}?, a little less than half, still retains 

 much of the nutritive material from the egg, by means of which the 

 nauplius is to be nourished during several moults until it can seek a 

 host and get its own food. These yolk granules make this portion of 

 the body opaque and nothing of the internal structure can be seen 



