296 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



stoma ; and the plate which stretches backward and supports 

 the labrum, within its posterior forked boundary, is the en- 

 dost oma. 



The middle of the dorsal surface of the carapace is marked 

 somewhat nearer its posterior than its anterior boundary by 

 a short transverse depression, wdiich is continued on each side 

 forward and outward, and then curves directly outward to the 

 edge of the carapace (Fig. 76, cs). Further than this I 

 cannot trace this homologue of the cervical groove of Astacus. 



Fig, 76.— Of the two upper fisnres, the left represents the dorsal surface of the cara- 

 pace of Carcinus moenas : f, rostrum; o, orbit; cs. cervical groove; q^, epigastric 

 lobe; g'2 jirotogaptric ; g'^, mesogastric ; .9*, hypogastric; g-\ urogastric; c, c', an- 

 terior and posterior cardiac; A, ht-patic; b^,b-, b^, epibranchial, mesobranchial 

 and melabranchlal lobes. The loM'er figure represents a ventral view of the an- 

 terior half of the same carapace: «, rostral septum; 6, antennar}' sternum ; c, 

 suture between these; d, siipraciliary lobe; e, internal suborbi tar lobe; /, anten- 

 na ; (7, articular cavity for the ophthalmic peduncle ; h, tlie same for the anten- 

 nule ; 0, orbit ; sh, subhepatic region ; ep, anterior pleural region. The right- 

 hand upper figure gives a side-view of the rarapace of Stenorhynchvs phalangium, 

 the common " spider-crab : " o. orbit ; / ',/^, rostrum ; «/, autennule ; at, antenna ; 

 €/?, epistoma. 



Elevations and depressions upon the surface of the carapace 

 in front of the cervical groove, which, as in Astacus^ is com- 

 posed of the connate terga of the six cephalic somites, mark 



