42 Journal of Comparative Neurology. 



7. The 2nd maxillary nerve arises from the first ganglion 

 back of the infra-oesophageal ganglion. 



8. From the last thoracic ganglion arise one unpaired and 

 two paired nerves. The paired nerves are the leg nerves; the 

 unpaired nerve is the abdominal nerve. The abdominal nerve 

 innervates the genital apparatus. 



9. There is a median compound triune eye. The eye is 

 situated near the dorsal surface. Each of the three divisions 

 of this eye is suppHed with retinal cells and a lens. The nerve 

 enters the outer ends of the retinal cells. In most of the fresh- 

 water Cypridce the component parts of this eye are closely ap- 

 proximated. In Notodrojnas, on the contrary, the three parts 

 are widely separated. 



10. In most of the fresh-water Cypridcs the optic nerve 

 is a median unpaired structure, which splits into three branches. 

 In Notodronias, however, there are three distinct optic nerves. 



11. In the front part of the body, between the base of 

 the antennae and the upper lip, there is a pair of pear-shaped 

 sensory organs. These are probably simple eyes. This organ 

 is innervated by a branch of the labial nerve. 



12. At the base of the antennule there is an auditory 

 organ. 



13. Bordering the mouth there are three pairs of similar 

 sense organs. These organs lie in the upper lip, at the base of 

 the mandibular teeth, and in the lower lip. They are innervated 

 by branches of the following nerves : labial, mandibular, and 

 labral. 



14. On the third segment of the second antenna there is 

 the so-called olfactory organ. This organ consists of three seg- 

 ments ; the basal, the middle, and the end piece. The nerve 

 enters the basal portion and extends to the base of the middle 

 piece, where it terminates in a knob-like swelling. 



15. In addition to the above sense organs there are sev- 

 eral types of sensory setae. 



