CRUSTACEA. 



Sometimes the shell is trapezoidal or ovoid, or is shaped like a heart 

 truncated posteriorly. The ocular pedicles, inserted at a short dis- 

 tance from the middle of its anterior margin, extend to its anterior 

 angles, or even beyond them. 



Commencing with those whose shell is transversely quadrilateral, 

 widened before and narrowed behind, or which has the form of an 

 egg, we first observe the 



MACROPHTHALMUS, Lat. 



Where the shell, as in the Gonoplaces, is trapezoidal, and the claws 

 are long and narrow; the ocular pedicles are slender, elongated, and 

 lodged in a groove under the anterior margin of the shell. The 

 first joint of the intermediate antennae is rather transverse than lon- 

 gitudinal, and the two which terminate them are very distinct and 

 of a mean size. The external foot-jaws are approximated inferiorly 

 at their inner edge, leaving no interval between them, and their third 

 joint is transverse. 



They* inhabit the Eastern Ocean, and the seas of New Holland. 



The following, which constitute the subgenera Gelasimus^ Ocy- 

 pode, and Mictyris, inhabit burrows, are remarkable for the celerity of 

 their course, and have the fourth pair of feet, and next to them, the 

 third, longer than the others. The intermediate antennae are exces- 

 sively small, and hardly bifid, at their extremity; the[radical joint is 

 nearly longitudinal. They are peculiar to hot climates. 



Here the shell is solid, of a quadrilateral or trapezoidal form, widest 

 before. 



GELASIMUS, Lat. UCA, Leach. 



Eyes terminating their pedicles like a small head ; third joint of 

 the external foot-jaws forming a transverse square ; last segment of 

 the tail of the males almost semi-circular, that of the females nearly 

 orbicular. 



The lateral antennae are longer, and more slender in proportion, than 

 those of the Ocypodes. One of the claws, now the right, and then 

 the left, varying in individuals of the same species, is much larger than 

 the other ; the fingers of the small one are frequently shaped like a 

 spoon or spatula. The animal closes the entrance of its burrow, 

 which it excavates in the vicinity of the sea-shore, or in marshy 

 places, with its large claw. These burrows are cylindrical, oblique, 

 very deep, and placed close to each other, but are usually inhabited 

 by a single individual. Their habit of holding the large claw in an 

 upright position before the body, as if making an appellative gesture, 

 has obtained for them the name of Calling- Crabs (Cancer vocans). 

 One species, observed by Bosc., in South Carolina, passes the three 



* Gonoplax transversus, Latr., Encyc. Method., Hist. Nat., ccxcvii, 2 ; Cancer 

 brevis, Herbst., Ix, 4. The Gonoplace de Latreille, a fossil species described by 

 Desmarest, Hist. Nat. des Crust. Foss., IX, 1 4, and perhaps also his G. incise, 

 IX, 5, 6, may be a Macrophthalmus ; generally speaking, however, his fossil Gono- 

 places are Gelasimi. The species he calls Gelasimc luisante, VIII, 7, 8, does not 

 appear to differ from the living one which I have called the maracoani, Encyc. Method., 

 Ib., ccxcvi, J. 



