NO. 3 BARNARD: THE PHOXOCEPHALIDAE 193 



Third phonal epimera. — Differences in convexity and distortion 

 of the posterior edges of the third epimera in males have been discussed 

 previously. 



Third uropods. — In general the third uropods of males are more 

 setose and the inner rami longer than in females. In species such as P. 

 calcaratus (Plate 26, fig. P) the female inner ramus is short and scale- 

 like while in P. obtusidens (Plate 34, fig. L) it is as long as article 1 

 of the outer ramus, thus quite masculine. In most species examined 

 there appears to be little difference between juvenile and adult females 

 regarding the third uropods but in P. obtusidens the inner ramus is short 

 in juveniles and long in adult females. 



In the process of maturing, males show a progressive change in 

 length of the inner ramus, until it approximates the outer ramus in 

 length. Increase in setation of both rami takes places so that both bear 

 long plumose setae in adult males. 



Urosome. — In males the proximal part of pleonal segment 4 is 

 strongly depressed while in females it is nearly flush with segment 3. 



The several dimorphic sexual conditions and their variability in 

 paraphoxids must be kept in mind when identifying these animals, so 

 that erection of erroneous new species does not occur. 



Key to the Genus Paraphoxus 

 1. Rostrum abruptly narrowed in front of eyes (Trichophoxus) 2 



1. Rostrum tapering evenly in front of eyes (Paraphoxus) 21 



2. Article 5 of gnathopod 1 shorter than article 6 3 



2. Article 5 of gnathopod 1 longer than or equal to article 6 5 



3. Article 2 of peraeopod 5 extends down to end of 



article 5 barnardi 



3. Article 2 of peraeopod 5 extends down to end of article 4 or less 4 



4. Articles 4-5 of peraeopod 4 equally expanded nasutus 



4. Article 5 of peraeopod 4 much narrower than 



article 4 floridanus 



5. Peraeopod 5 with 2 large spurs bicuspidatus 



5. Peraeopod 5 lacks spurs 6 



6. Article 2 of peraeopod 5 with large teeth 7 



6. Article 2 of peraeopod 5 with small teeth 9 



7. Epistome unproduced 8 



7. Epistome produced and very long variatus 



8. Peraeopod 5 with 3 large teeth tridcntatus 



8. Peraeopod 5 with 4-5 medium, uneven teeth hetcrocuspidatus 



