44 CRUSTACEA OF ALABAMA. 



middle produced into a very acute prolongation anteriorly with lines passing obliquely 

 outward and forward as well as others posteriorly. Front abruptly deflexed. Gill cover 

 rhombic, finely sculptured and pustutose, with minute spines, distant from median line 

 in front 3.5 mm. Antennules minute, with the basal portion (probably representing 

 combined coxocerite and basicerite), excavated tc receive the four-jointed endocerite, the 

 terminal joint or protocerite being in the form of clawfitting into the penultimate seg- 

 ment of carpocerite. 



The antennae are also minute and are enclosed by a basin opening into that of the 

 orbit. The basicerite bears a blunt mallated scaphocerite, with its brush of long and 

 dense setae. The ischiocerite is large and also bears a tuft of setae, the remainder of the 

 endocerite being in the form of a multiarticulate fiaggellum. The jaws are rather small, 

 the maxillae are of the usual form, the maxillipeds being more characteristic. Of the 

 latter, the second or outer pair has a strong coxopodite bearing a long lamellate plate 

 (the epipodite) and a pair of well-developed gills while the gill-cover (epipodite) has a 

 small rudiment of a gill. The basipoclite is small bearing the slender palp or exopodite, 

 the basal joint of which reaches only to the middle of the second joint of the inner limb. 

 The latter, or endopodite, is long, with an irregularly pentagonal ischiopodite and a long, 

 narrowly oboval meropodite, both these segments being crossed by an oblique hairy 

 ridge. The three following joints are small and setose, the terminal one, or dactylopo- 

 dite, being very small and oval. The chelipeds differ little in the sexes, being alike on 

 both sides. Those of the male have the hands relatively thicker .and hence the under 

 outline more curved and the finger abruptly flexed. The hand and the finger are simply 

 punctate, while the opposible margins each bear three nearly equidistant teeth with in- 

 tervening smaller ones. The carpopodite is not spiny. The remaining ambulatory 

 limbs are armed with simple spines, nearly smooth. Abdomen of male elongate, nar- 

 row, pentagonal, with minute free fin, that of female broadly ovate or seven-sided, ter- 

 minal fin set in emargination of fifth joint, short oval ; abdomen covering free sternae 

 completely in the female. Second pair of abdominal appendages in the male simple, 

 slightly curved, first pair tortuous, narrowed toward apex, emarginate. 



FAMILY MACROPHTHALMID^. 



This family includes the well-known fiddler crabs, of which the best illustration is 

 afforded by the common 



Genus Gelasimus, Latr. 



Carapace rhomboidal, much wider in front, eyes on long peduncles, male with the 

 left (or right) chelliped much larger than the other. 



GelasiniUS VOCatOr. Martens. 



(Plate V, Fig. 4.) 

 = G. pngnax, Smith. 

 A careful comparison of specimens from Mobile bay with those distributed by the 



