72 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Each of these consists of an outer ' opercular ' lobe and 

 an inner lobe. In the male the inner margins of the 

 outer lobes of the first pair may, or may not, be produced 

 into short spinous processes ; the inner margins of the 

 second pair are produced into two long slender styles for 

 copulatory purposes. 



The terminal segment or telson is composed of the 

 last two segments of the metasome, which are fused to 

 form a rather broad terminal segment. The posterior 

 edge is evenly rounded ; the lateral portions are acuminate 

 and subtend a sinus in which the terminal pair of uropoda 

 arise. Each of the terminal uropoda consists of a fairly 

 stout basal portion, from which the styliform appendages 

 arise. The anus is a longitudinal slit on the ventral side 

 of the terminal segment. 



The external apertures are — the mouth, the openings 

 of the maxillary excretory organs on the protopodites of 

 the second maxillae, the openings of the oviducts at the 

 base of the fifth pair of pereiopods, or of the vasa 

 def erentia at the posterior border of the ventral side of the 

 seventh thoracic segment, and the anus. 



Appendages. 



The first pair of antennae (PI. II., Fig. 1) may be truly 

 called antennules, as they are extremely small, measuring 

 a little over 1 mm. in length. They are situated internal 

 to, and at the base of, the second antennae. They are 

 triarticulate, the terminal joint being quite rudimentary 

 and bearing two terminal groups of small setae. 



The second pair of antennae (PI. II., Fig. 2) are long, 

 attaining a length of 25 mm. in the male and 14 mm. in the 

 female ; when folded back they extend to the posterior 

 border of the fourth thoracic segment. The protopodite 

 is composed of five joints, the fourth and fifth being the 



