DECAPODA. ANOMUBA. 



541 



Fam. 4. Lithodidae. Carapace broadly ovate, uneven, with prominent 



rostrum ; 1st antennae with cylindrical peduncles and 2 short flagella ; 



2nd with an acicle ; 1st trunk-legs chelate, 5th slender, chelate, folded in 



the bra n c h i a 1 



chambers. Ab- 



domen bent 



UTL d e r thorax, 



without u r o - 



pods, 3-5 terga 



represented by 



paired la t e r a 1 



plates, with the 



a ppendages 



only present in 



the female, and 



uns y m m e t r i- 



cally developed. 



Inhabit shallow 



water of the 



arctic or ant- 

 arctic zones, and 



the intermediate 



cold, deep water in temperate and tropical regions, though some are 



littoral. They are regarded as derived from the Pagurid stock, having 



partially regained their bilateral symmetry, and acquired a crab-like 



appearance. The larva of Lithodes hatches in metazoaea form. 



Sub-fam. 1. Hapalogastrinae ( = Hapalogastrica Brandt). Hapalo- 

 gaster and Dermaturus Brandt ; Placetron Schalfew. 



Sub-fam. 2. Ostracogastrinae. Phyllolithodes Brandt ; Neolithodes 

 M.-E. and Bouv. ; Paralithodes Brandt ; Lithodes Latr., robust and 

 covered with spines, Some spp. British. Widely distributed in deep 

 water, and littoral. Acantholithus Stps. ; Paralomis White ; Rhino- 

 lithodes Brandt ; Echidnocerus W T hite ; Cryptoliihodes Brandt. 



FIG. 329. Birgus latro. Diagrammatic transverse section in the 

 region of the heart, a^-a^ pulmonary or shell vessels leading from 

 the heart ; ah respiratory chamber ; ek branchial blood-canals lead- 

 ing to the heart ; el pulmonary vessels leading to the heart; el-i the 

 same near the entrance into the pericardium ; h heart ; k bran- 

 chiae ; kd branchiostegite ; Ib respiratory tufts ; p pericardium. 

 (From Lang, after Semper.) 



Tribe 3. GALATHEIDEA. 



Body symmetrical, depressed. Abdomen well developed usually 

 ventrally flexed, but not, except in the Porcellanidae, applied to the 

 sterna of the thorax, with uropods. Rostrum usually well developed. 3rd 

 maxillipeds 7-segmented, leg-like or with the basal segments expanded. 

 The 1st trunk-legs alone carry regular chelae, the 5th slender and folded 

 in the branchial chamber. Gills usually phyllobranchiate (tricho- 

 branchiate in Aeglea). Generative orifices on coxae. Aeglea is the only 

 fresh-water genus, the others are littoral or deep sea. 



Fam. 1. Aeglidae. Gills trichobranchiate. Eight arthrobranchiae 

 and 3 rudimentary pleurobranchiae. 2nd antennae without a scale. 

 Aeglea Leach. The sole sp. A. laevis Lat. in mountain streams in S. 

 America. 



Fam. 2. Chirostylidae. Gills as in the remaining families, i.e. phyllo- 

 branchiate : 7 arthrobranchiae and 4, pleurobranchiae. Ant. 2 with 

 spine-like scale. Chirostylus Ortm., trunk-legs very long. Uroptychus 

 Hend. ; Eumunida Smith. 



Fam. 3. Galatheidae. Rostrum well developed, triangular or spine- 



