270 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



FIG. 280. LlMNORIA L I G N O R U M 



(AFTER HARGER). a, FIRST AN- 

 TENNA. x25. 6, SECOND AXTF.XNA. 

 x 25. c, MAXILLIPED. x 25. <l, 

 SECOND MAXILLA, x 25. e, FIRST 

 MAXILLA, x 25. e', DISTAL END OF 



FIRST MAXILLA. X 66. /, MANDI- 

 BLE. X 25. 



FIG. 281. LlMNORIA LIGNOKTM 



(AFTER HARGER). o, LAST SEG- 

 MENT OF ABDOMEN WITH UROPODA. 



x 10. b, UROPOD. x 30. c, FIRST 



PAIR OF PLEOPODA. X 20. d, SEC- 

 OND PLEOPOD OF MALE. X 20. 



branch reaches the 



first; the fifth article is about as long as the fourth. The flagellum is 

 composed of two or three indistinctly denned articles. The maxilli- 



peds have a palp of five articles. The pulp of 

 ^ ne man -dibles i* composed of three articles. 



The first seg- 

 ment of the tho- 

 rax is longer than 

 any of those fol- 

 lowing, which are 

 subequal; it is al- 

 most twice aslong. 

 Epimera are dis- 

 tinctly separated 

 on all the segments 

 with the excep- 

 tion of the first. 



The abdomen is composed of six distinct 

 segments. The first five are short and sub- 

 equal. The sixth or terminal segment has 

 the posterior margin widely rounded. The 

 uropoda are laterally placed. The outer 

 branch is small and rudimentar}^. The inner 

 extremity of the abdomen. 

 All the legs are ambulatory. 



Family XI. SPH^ROMID^. 



Body short, oval, convex. Head transverse. 



First and second pairs of antennae multiarticulate with evident dis- 

 tinction into peduncle and flagellum. Mandibles with palps. Anterior 

 segments of abdomen united into a single segment, which, with the 

 large terminal segment, forms a biarticulate abdomen. 



Uropoda lateral, forming, with the terminal abdominal segment, a 

 caudal fan. Outer branch of uropoda, when present, movable. Inner 

 branch fixed, immovable. 



Epimera united with the thoracic segments. 



ANALYTICAL KEY TO THE GENERA OF THE FAMILY SPH^CROMID^. 



a. Outer branch of the uropoda entirety wanting Genus Ancinus Milne Edwards 



a'. Both branches of the uropoda present. 



b. Outer branch of the uropoda small, rudimentary Genus Cassidisca, new genus 



b' '. Outer branch of the uropoda not rudimentary. 

 c. First and second pairs of legs subchelate in male; only first pair subchelate 



in female Genus T<'rti<-<-/< Richardson 



cf. Legs all ambulatory. 



d. Outer branch of uropoda capable of folding under inner branch; both 

 branches similar in shape and salient. 



