380 



2. Hyperioides sibaginis (Stebbing, 1888) (Fig. 161) 



Stebbing, 1888: 1379 (Hyperia); Bovallius, 1889: 201; (?) Pirlot, 

 1930: 18; Bowman, 1973:33. 



Length of adult specimens 4-6 mm. 



The head is round and longer than the first three somites of the 

 pereon together. The eyes occupy not only the dorsal, but also the greater 

 part of the lateral surface of the head. 



In females antennae I are two-segmented and antennae II one-seg- 

 mented; their length is approximately the same. Pereopods I and II are the 

 same as in the preceding species,but the distal process of the 5th segment 

 of pereopods II is shorter and does not extend to half the length of the 

 6th segment. The 5th and 6th segments of pereopods V and VI bear not 

 only sparse spines on the anterior margin, but also a dense row of short 

 thin setae. Pereopods VII are the same in structure as in H. longipes. 



The posterior distal angle of epimeron I is round but in epimerons II 

 and III acute. The uropods are much longer and thinner; the basipodite 

 of uropods III is almost 1/3 as wide as long and 1.5 times longer than 

 the exopodite. 

 310 Distribution: Found in the tropical waters of the Pacific Ocean: 



northern, central, and equatorial regions, of the Philippines, Line Islands, 

 and the Gulf of Panama. It lives mainly in the upper 200 m layer. 



10. Genus Lestrigonus Milne-Edwards, 1830 



Milne-Edwards, 1830: 392; 1840:81; Bowman, 1973: 33. 



A minute species (2-5 mm) with a highly bulged pereon. The head is 

 spherical and the eyes occupy most of its surface. The anterior somites 

 of the pereon [I-III (V) in females and I-II (IV) in males] are fused; 

 the number of fused somites is specific to each species and the number 

 always more in females than in males. Antennae I in females are two- 

 segmented; antennae II are one-segmented and rudimentary. The epis- 

 tome projects and is convex anteriorly. The mandibular palp is absent in 

 females. The outer lobe of maxillae I bears three apical spines. The outer 

 lobes of the maxillipeds are long and fairly narrow while the inner lobes 

 are comparatively larger. The coxal plates are fused with the somites of 

 the pereon. Pereopods I have a subchela or a poorly developed chela. 

 Pereopods II have a chela and the distal process of the 5th segment is 

 spoon-shaped. Pereopods V-Vii are generally longer than pairs III-IV. 

 Pereopods VI are generally longer than the mutually equal pereopods V 

 and VII.^ 



Type species: Lestrigonus fabrei Milne-Edwards, 1830. 



' Diagnosis of the genus and description of its constituent species are after Bowman 

 (1979), with some emendations. 



