NO- 3574 COPEPOD CRUSTACEANS — ^LEWIS 93 



phoridae and in his subfamily Tiixophorinae, which includes both 

 Midias and Tuxophorus, the latter of which has distinct alae on the 

 fourth pedigerous segment. 



The division between the Cahgidae and the Euryphoridae is tenuous, 

 both famihes sharing common characteristics. Dentigryps, a caligid 

 genus, for example, possesses euryphorid-like fifth legs; Pupulina, a 

 caligid, has euryphorid-like extensions of the genital segment. Addi- 

 tionally, one of the characteristics of the euryphorids is the presence of 

 a biramous condition in the first 4 pairs of thoracic legs, yet Gloiopotes, 

 a distinct euryphorid, has a distinctly uniramous fourth leg. The 

 euryphorids are considered to be a transition group, between the cali- 

 gids and the pandarids, and as such there are characteristics of the 

 family that associate them with either or both the caligids and the 

 pandarids. 



Midias, Dentigryps, and a few other genera exhibit some characteris- 

 tics which approach those of the Euryphoridae (see Lewis, 1964b, for a 

 discussion of the association of Dentigryps with the Euryphoridae). 

 Midias is characterized by having certain parts of the body heavily 

 sclerotized. This condition is particularly noticeable on the tergal 

 region and on some of the projections on the body and the appendages. 

 The "dorsal plates," used as a euryphorid characteristic by Wilson, are 

 not distinct plates but rather are thickenings of the tergum which are 

 heavily sclerotized and do not project as do the plates of the alae- 

 bearing groups. These thickenings are also found in other caligids 

 (e.g., Caligus productus Dana, 1853). Of the other characteristics used 

 by Wilson, the inflated genital segment is not unique (e.g., Synestius, a 

 caligid), the lateral lobes of the first segment of the abdomen are also 

 found in DarteveUia, and the posterior lobes on the abdomen are pres- 

 ent in Dentigryps curtus Wilson, 1913, both of the last two being 

 caligids. Further, the posterior lobes are not described for Midias 

 carangis Rangnekar, 1956. The possession of a 2-segmented endopo- 

 dite on the first thoracic leg is a qualifying characteristic although the 

 endopodite is strongly reduced and no larger than that found in many 

 caligids. 



Midias is here placed in the Caligidae because of the absence of dis- 

 tinctly euryphorid characteristics, the presence of a uniramous, 

 4-segmented fourth thoracic leg, the presence of well-developed lu- 

 nules, the presence of a spinelike projection as part of the postantennal 

 process, and the presence of a reduced endopodite on the first thoracic 

 leg. The author also accepts the fact that most of these characteris- 

 tics are as open to criticism as are those Wilson used to include the 

 genus in the Euryphoridae. 



