84 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 38. 



ORBIMORPHUS CONSTRICTUS, new species. 



Body of adult female ovate, somewhat irregular in outline. 

 Head large, and with a narrow frontal border. Eyes absent. 

 First pair of antennae small, composed of three articles, the terminal one 

 being minute. Second pair of antennae concealed by the mouth parts. 



The seven segments of the thorax are distinct. Lateral bosses are 

 present on the first four. Lateral to these are the epimeral plates, 

 which extend the entire length of the lateral margin, and which are 



larger on one side of 

 the body than on the 

 other. The epimera of 

 the last three segments 

 are also well developed. 



The abdomen is com- 

 posed of five segments, 

 the fifth or terminal 

 segment being small and 

 not provided with pleu- 

 ral plates as are the first 

 four segments. The seg- 

 ments of the abdomen 

 are rather indistinctly 

 defined in the middle 

 of the dorsal region. 

 There are four pairs of 

 double -branched pleo- 

 pods, the lamellae being 

 leaf-like. The uropods 

 are a pair of double- 

 branched oval lamella?, 

 a little shorter than 

 the branches of thepleo- 

 pods, all of which en- 

 circle the abdomen, and 

 project beyond the pleu- 

 ral plates of the abdom- 

 inal segments. There 

 are seven pairs of prehensle legs, all furnished with a high rounded 

 carina on the basis. There are five pairs of incubatory plates, the 

 first pair having the distal half produced in a small lobe. 



The male is narrowly elongate. The head is large, transversely 

 oval. Eyes are small and distinct. All seven segments of the 

 thorax are distinctly defined, with lateral margins not contiguous, but 

 separated by a small indentation. The segments of the abdomen are all 

 united to form a single tapering segment, with posterior extremity 



FIG. 5.— ORBIMORPHUS CONSTRICTUS. 

 b, FIRST LAMELLA OF MARSUPIUM. 

 FEMALE. X 41. d, MALE. X 41. 



a, ADULT FEMALE. X 14|. 

 X 23. C, SEVENTH LEG OF 



