NO. 3 BARNARD: THE PHOXOCEPHALIDAE 185 



described below have this character, while many do not. It remains 

 to reexamine many other phoxocephalids for this character which is 

 rarely mentioned in the literature (Table 1). 



The length and degree of acuteness of the epistomal process or 

 the lack of it vary so much interspecifically that groups of otherwise 

 unidentified specimens may be segregated by its shape. Since it is 

 difficult to see, the following technique is described for its rapid 

 discernment: The writer, who is right-handed, holds the animal 

 under the stereomicroscope, on its right side with the head to the right, 

 the ventral side away from him; the left hand holds the specimen in a 

 forceps in this position; the right hand holds a needle which is used 

 to press the antennae and mandibular palps dorsally or toward the 

 observer, thus revealing the epistome for quick observation. 



In any one species the shape of the epistome is sufficiently uniform 

 that specific differences are evident. Four basic types of epistome have 

 been noted by the writer : ( 1 ) unproduced and anteriorly rounded, some- 

 times with a minute apical cone, the epistome small or massive (P. 

 oculatus, Plate 28, fig. B; P. obtusidens, Plate 32, fig. D) ; (2) slightly 

 produced, bearing a small, acute anterior tubercle (P. lucubrans, Plate 

 12, fig. D) ; (3) a short tooth-like process, often quite massive as on P. 

 similis (Plate 22, fig. E) ; (4) a long, acute, almost needle-like, oc- 

 casionally slightly curved process (P. epistomus, Plate 6, fig. D). 



Juvenile specimens may have the epistome slightly less pronounced 

 than in adults. 



Gnathopods. — Unlike most other amphipods the gnathopods of 

 Paraphoxus show no sexual dimorphism. In any one species they are 

 rather uniform in both juveniles and adults, although in a few cases, 

 such as P. epistomus, the juveniles will have fifth articles shorter than 

 in adults. It is imperative that adequate figures of both gnathopods 

 be given to facilitate systematic distinction. Often such specific dif- 

 ferences occur which have been used by the writer as a final con- 

 firmation in a specific identification. 



Usually, the fifth article of the second gnathopod is shorter than 

 the corresponding article of gnathopod 1 but the degree of shortness 

 varies in different species. Frequently the sixth article is broader in the 

 second gnathopod than in the first. 



The lengths of articles 5 and 6 are useful systematic characters. 

 The fifth article may range from much shorter to much longer than 

 article 6. Two species closely related in other characters, such as P. 



