50 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



Pagina tunica Cressey, 1964 



Figures 243-267 

 Pagina tunica Cressey, 1964, p. 285. 



Specimens studied. — 21 specimens (18 females and 3 males) col- 

 lected from Alopias superciliosus (Lowe) caught at Majunga, Mada- 

 gascar, Holotype female, allotype male, and 8 paratype females in 

 alcohol deposited in the U.S. National Museum, 3 paratype females 

 in alcohol deposited in the Collection of the Centre d'Oceanographic 

 et des Peches de Nosy Be, Madagascar, and the remaining paratypes 

 in the author's collection. 



Other specimens studied. — A single collection from Alopias 

 superciliosus from Nosy Be, Madagascar; a single collection from the 

 same host in the Pacific (0°38'N, 124°23'W). 



Female. — Body form as in figures 243 and 244. Total length, 

 based on an average of 4 specimens, including caudal rami but not 

 setae, 17.9 mm. Greatest width (measured at the widest part of 

 cephalon) 5.8 mm. 



Cephalon nearly round, slightly longer than wide, measuring 6.0 by 

 5.8 mm (measurements including marginal fringe). Posterior corners 

 of cephalon projecting distally. First thoracic segment fused with 

 head. Second segment distinct with 2 lateral lobes extending to 

 posterior margin of third thoracic segment, thus incorporating the 

 smaller third segment within its posterior border. Fourth thoracic 

 segment with dorsal plate consisting of 2 conspicuous winglike lobes. 

 The distal corner of this plate extends only slightly over anterior 

 corner of genital segment. Genital segment large, its greatest length 

 4.6 mm and its greatest width at the posterior comers 3.8 mm. Pos- 

 terior corners produced to form 2 short lobes. Abdomen 2-segmented, 

 both segments possessing a conspicuous dorsal plate. From the dorsal 

 aspect abdominal plates covering rest of abdomen. Ventrally the 

 first abdominal segment (fig. 248) as wide as long, measuring 1.5 by 

 1.5 mm. Dorsal plate of this segment extending over rest of abdomen 

 and with a deep median sinus dividing it into 2 long lobes (see figs. 

 243, 244). Second abdominal segment also as long as wide and 

 measuring ventrally 2.1 by 2.1 mm. Its dorsal plate composed of 

 only a single lobe and extending over proximal ends of caudal rami 

 (see figs. 243, 245). Caudal ramus (fig. 245) large, comprising almost 

 one-fourth of total body length. Each ramus about 4 times as long 

 as wide measuring 4.2 by 1.3 mm. Distal end of ramus bearing 6 

 setae. The outermost and innermost small and naked, but median 4 

 plumose and all nearly equal in length, longest measuring 0.4 mm. 

 Outer border heavily sclerotized while inner only weakly so and often 

 appearing wrinkled in preserved specimens. 



