E. A. Andretos — Anatomy of the /Sjnder Crab. 119 



EXPLANATION OF PLATES. 

 Plate XXV. 



Fig. 1. — Male, witli the carapace removed: about natural size. On the left the 

 dermis has been folded outward, as has also the cuticnlar lining of the posterior 

 part of the branchial cavity. On the right these have been removed, and also the 

 portion of the liver, testis and antennary artery, lying over the anterior part of the 

 branchial cavity, and the branchiae have been turned outward, showing the floor of 

 the cavity. On this side, also, the carapace has been removed from about the eye 

 and the attachment of the autero-gastric muscle : 



a, antenna ; ab, abductor of mandible and mu.scle from the first maxilla, here 

 attached to the carapace; af, afferent vessel of branchia; ag, antero-gastric muscle; 

 op, anterior wall of the pericardium ; b, muscular bands connecting the cuticular cov- 

 ering of the anterior part of the branchial cavity with the carapace; be, branchio-car. 

 diac canal: br\-br1, branchiae: c, cuticular covering of the branchial chamber; cp, 

 cardio-pyloric muscle; d, dermis ; e, eye; e/, efferent vessel of branchice; /, roof of the 

 efferent canal ; g, stomach ; gg, portion of the green gland ; h, heart, with four orifi- 

 ces and five supporting bands ; i, intestine; I, liver; m, m', great and small adductors 

 of the mandible ; the latter, on the right, is separated from the postero-gastric mus- 

 cle to show the testis passing below their common origin ; o, line of union of the dor- 

 sal surface of the abdomen and the refiexed part of the carapace ; p, prolongation of o, 

 connecting it with the edges of the flanks ; pg, postero-gastric muscle ; pt, pterocar- 

 diac ossicle ; r, antennary artery, with main branches ; r', ophthalmic artery ; r", 

 origin of sternal artery ; r"", superior abdominal artery ; rs, rostrum ; S, S', S", epi- 

 podites of the first, second and third maxillipeds ; sp, supero-pyloric muscle ; t, tes. 

 tis ; f, posterior, less convoluted portion ; i", accessory organ connected with the 

 vas deferens ; u, i^yloric ca^cal appendage ; u', posterior unpaired ctecal appendage ; 

 w, refiexed cuticular portion of the carapace covering the origin of the abdomen ; x, 

 muscular bands joining the upper inner edge of the apodemal framework of the 

 carapace; z, muscles which appear to assist in respiration by raising the fold of the 

 carapace, which partly closes the posterior opening of the branchial cavity. 



Fig. 2. — Upper, or true ventral surface of male abdomen ; about natural size. 

 The first appendage has been removed on the right to show the second : a 

 anus ; 6, c, d, joints of the first appendage ; ?/, c', d\ those of the second ; o, cavity 

 into which a projection of the thorax fits and holds the abdomen in place ; p, process 

 by which the abdomen is attached to the edge of the fianks ; xv-xxi, seven termi- 

 nal segments forming the abdomen. 



Fig. 3. — Upper or true ventral surface of female ; about natural size. The 

 appendages of the right side have been removed : en, ex, pr, endopodite, exopodite 

 and protopodite of the first appendage ; other letters as in fig. 2. 



Figs. 4, 4a. — Appendages of the male abdomen; anterior face of the first and 

 second appendage on the right side ; enlarged about two diameters : b, c, d, b\ c', d', 

 joints of the first and of the second appendages ; p. membranous process near the 

 tip of the first appendage ; p', membranous papilla-like termination of the second 

 appendage. 



Fig. 5. — Posterior face of the right abdominal appendage of the second pair ; 

 female; enlarged about two diameters: ex, exopodite; en, endopodite; pn-, membra- 

 nous articulating portion, representmg the protopodite. 



