VI 



OXYRHYNCHA CATOMETOPA 



193 



c 



G 



the gill-chambers (G) greatly swollen and enlarged to make uj 

 for the scarcity of oxygen in these 

 deep regions. 



Fam. 1. Maiidae. The chelipedes 

 are not much larger than the other 

 legs, but are very mobile. Orbits 

 incomplete. A very large family, 

 including all the true Spider -crabs, 

 very common in the Atlantic and 

 Mediterranean littoral. Inachus, Pisa, 

 Hyas, Stenorl ////<// i/.s, Maia, Enceplia- 

 loides (Fig. 132). 



Fam. 2. Parthenopidae. - - The 

 chelipedes are much larger than FIG. 132. Encephaloides arm- 



, , . , , strinigi, x 1. The long walk- 



the Other legs. Orbits Complete. i ng legs are omitted. C, Greal 



LambruB (Fig. 133), Parthenope. chela ; G > ot ' i]w g"^3 



, swollen gill -chambers. (After 



Fam. 3. Hymenosomatidae. Ihe Aicock.) 

 carapace is thin and flat ; the cheli- 

 pedes are neither very long nor especially mobile. There are no 



orbits, and the male openings 

 are on the sternum. ('liarac- 



'' .^ Kl "^X teristic of the Antarctic seas. 



fly inenosoma, Trigonoplax. 



Tribe 5. Catometopa. 



These Crabs resemble the 

 < 'vclometopa in general ap- 

 pearance, but the carapace i- 



FIG. 13:!. 7-<'/,//-,v'.s-,,,,V,',st, x 1. (After very S(|Uare i u oullilir. ;iud 

 .Milne- Edwards and Bouvier.) ,. 



its margins are nc\cr so \\> j l 



pru\ id.-d with sj.iiM-s as in the Gyclometo]);i. The position oJ 

 the m;dc .uvnilal openin;_;< is peculiar, since they lie u|><ni tin- 

 sternum, and are connected with the copulatnry appendages 

 uiiuii the abdomen liy means <if furrows excavated in the 

 sternum. The ( 'utoiiictopii are either litt-.i-.-d or shallow wal 

 tbi'ins, or else they live entirely on land. The < Ir.-ipsidae are 

 marine ('rali>, I'url, //>// />xti* ni<tnin>r<it n* ' V\'^. \ '' -I al Naples 

 bcinu exce.-din-ly coiiimon <>n rocks at hi-b-\\ater mark OV61 

 which it scuttles at a -Teat rate: in Hi.- Mediterranean it takes 

 VOL. IV 



