2fi8 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Family X. LIMNORIID^. 



Body oblong, subdepressed, contractile into a ball. Head short 

 and blunt in front. Both pairs of antennas small, subequal; ftagella 

 short. Mouth parts normal. Mandibles without molar expansion; 

 with a small, three-jointed palp. Palp of maxillipeds composed of five 

 articles. Eyes lateral. 



Segments of thorax distinct; first segment longer than second. 

 Epimera well defined on all the segments of the thorax with the excep- 

 tion of the first. 



Abdomen composed of six distinct segments; terminal segment 

 large, broad, flattened above. 



Legs all ambulatory. 



Pleopods uniform in structure, both natatory and branchial; inner 

 plate of second pair in male with a stylet. 



Uropoda small, lateral; outer branch short, unguiform, almost obso- 

 lete; inner branch linear. 



44. Genus LIMNORIA Leach. 

 Only genus. With characters of family. 



pariuin quinque priorum per paria sensim longitudine et robore crescentes, paris 

 sexti et septimi prsecedentibus paulo breviores atque tenuiores, minus curvatte. 

 Carina pedum parium quattuor posteriorum evanida. 



Cauda profunde immersa, lateribus annulorum triuin priorum, saltern alterius 

 lateris, obtectis, annul! secundi, tertii, quarti, quinti conjunctim leviter curvatis, vix 

 convergentibus: convexiuscula, paulo vel vix latior quam longior, quam truncus 

 cum capite plus duplo brevior. Annulus primus magnam vel maximam partem 

 obtectus; annulus secundus, tertius, quartus longitudine subjequales, quam annulus 

 quintus fere sesqui breviores. Margo postieus annulorum quattuor priorum latissime 

 sinuatus; annuli quinti subrectus, obscure flexuosus. Anguli postici annul! secundi, 

 tertii, quarti, quinti prominuli, integri, breviter rotundati. Annulus analis breviter 

 subtriangulus, quam annulus quintus caudalis paulo angustior, sesqui ferme latior 

 quam longior (fere 5:7), annulis ceteris caudalibus conjunctis sesqui longior. Pedes 

 anales quam annulus analis paulo longiores; ram us interior quam exterior fere sesqui 

 brevior et paulo angustior, producte laminatus; ramus exterior subfalcatus, acutius- 

 culus, leviter flexuosus. Long. 8-18 mm. 



Color cereus, maculis majoribus vel minoribus, fuscis, racemosis, in series trans- 

 versas digestis, in medio corpore sparsus; oculi nigri. SCHIOSDTE and MKINERT, Nat. 

 Nat. Tidsskr. (3), XIV, 1883-84, pp. 390-395. 



For description of the male and the young of the second stage, see same reference, 

 pp. 392-395. 



See Sars for characters of family, Crust, of Norway, II, 1899, pp. 74-75. 



