1884.] NATURAL SCIENCES OF PHILADELPmA. 41 



posed ; characteristic, the substitution of a membraneous cup or 

 net, destitute of external ciliation, in the place of the ordinary 

 rotatory organs. 



Bibliog. — Leidy, Proc. Acad. Nat. Sci., 1857, 204; Meczinchow, Zeits.f. 

 wis. Zoologie, 1866, 346, Taf. XIX; Forbes, Am. Month. Micros. Jour., 

 1882, 102, 151. 



REFERENCES TO PLATE I. 



Fig. 1. Apsilus vorax (Dictyop7wra vorax of Leidy). a. Membraneous net. 

 6. Crop, c, c. Embryo, d. Mastax. e. CEsophagus. /. Oral aper- 

 ture, g. Vent. h. Muscular system of net. Seduced from drawing 

 by Leidy. The body is slightly wider in proportion to the net than in 

 original drawing. 



Fig. 2. Apsilus lentiformis Meczinchow. a, a. Antennae, b. Muscular 

 system of net. c. Crop. d. Mastax. e, e. Embryo. /. CEsophagus. 

 g. Purplish brown bodies. Beducedfrom drawing by Meczinchow. 



Fig. 3. Apsilus bucinedax (Cupelopagus bucinedax of Forbes), a. Net. 

 b. Oral aperture, c. Crop. d. Mastax. e, e. Embryo. /. (Esopha- 

 gus. Reduced from drawing by Forbes. 



Fig. 4. Apsilus bipera Foulke. a, a. Antennae, b. Muscular system of 

 net. c. Oral aperture, d. Crop. e. Secondary sacculated stomach. 

 /. Mastax. g. ffisophagus. h, h: Embryo, i. Enigmatical pur- 

 plish brown bodies attached to walls of body. 



Fig. 5. Apsilus lentiformis Meczinchow. a, a. Ganglion of the pouch. 

 Superficial view when closed. 



Fig. 6. Dorsal view of net of Apsilus lentiformis. a, a, a, a. Muscular 

 system. 



Fig. 7. Dorsal view of net of Apsilus bipera. a. Shield, b. Pointed 

 support, c. Portion of net above shield, d. Muscular system of 

 shield, e. Ciliated flaps extending up inside of net. 



