90 



PROCEEDINGS OF THE NATIONAL MUSEUM 

 Genus ACEROTISA Strand 



ACEROTISA PELLUCIDA. new speciea 



VOL. 86 



FlGtTRE 33 



Body flat, delicate and elliptical in outline; size of two preserved 

 specimens : 7.1 by 4.3 ; 5.7 by 3.8 mm. The median ventral sucker is 

 at the posterior end of the anterior third of the body; diameter, 0.2 

 mm. The cerebral eyes in the two specimens number 34 and 24, re- 

 spectively. They are arranged in two irregular, elongated gi'oups 

 anterior and posterior to the brain lobes on each side. There are 

 about 12 small eyes along the anterior margin; two near the median 

 line; three lateral to these in a longitudinal series; and two farther 

 toward the sides. The brain lies at the posterior end of the anterior 

 ninth of the body. A reticulate nervous system is easily seen all 

 around the margin and is especially clear at the anterior end. The 

 mouth is immediately behind the brain, about 1.0 mm from the ante- 

 rior end. The pharynx is tubular, 0.7 mm long and 0.5 mm wide. 



FiGDRB 33. — Acerotisa pellucida, new species : Dorsal view. 6, Brain ; e, eyes ; en, enteron; 

 g, gonads; p, pharynx; au, sucker; u, uterus; vd, vas deferens; cf, male opening; 

 $, female opening. 



