PLATE VII. 



The lettering is the samo in aU the figures. 



a Acontia. 



b Mesenteric filaments. 



c Stomata in tlio soptu. 

 c' Perioral stomata. 

 c^ Margiual stomata. 

 cij Cuticle. 



d Glandular streaks of the mesen- 

 teric lilaments. 



« Ciliated streaks of the mesenteric 

 lihimcnts. 

 ck Ectoderm. 

 en Endoderm. 



(/'Keproductive organs. 



h Septa, rh Diruotive septa. 



i Oral disk. 



k Wall. 

 I Pedal disk, 

 m Muscles. 

 mm Mesodermal muscles. 

 ml Longitudinal muscles of the septa. 

 ml^ Kctractor. 

 mp Parietobasilar muscle. 

 ml Tran.sverse muscles. 

 mr Radial muscles of the oral di.sk 

 and longitudinal muscles of the 

 tentacles 

 ins Circular muscle of the wall. 

 me Mesoderm. 

 n Urticating cells. 

 Ovicells. 



p Filamental apparatus of the ovicells. 

 p ' Process of the ovicell. 

 j/^ Apical set of epithelial cells. 



r Marginal spherules. 

 rh Directive septa. 



s QLsophagus. 

 so Openings of the oesophagus into 



the radial chambers. 

 sr CEsophageal grooves. 

 sz Lappets of the ce.sophagus. 



t Tentacles and tlie openings homolo- 

 gous with them. 

 t ' Principal tentacles. 

 t ^ Accessory tentacles. 



V Openings of the pedal disk. 



All statements given as to magnifying powers have reference to Zeiss's system. The magnifying powers amount to 



Oc. 2. 



10 D ... 



A 55 70 F ... 



95 125 J ... 



A with unscrewed front lens (unscr. A) magnifies with Oc. 1 



Oc. 1. 



6 



55 



95 



Oc. 1. 

 195 

 410 



470 



Oc. 2. 



240 

 550 



5S0 



30 times ; with Oc. 2 ; 40 times. 



Leiotealia nympJicea (figs. 1-5). 



Fig. 1. Transverse section through the oral disk. A, Oc. 2. 



Fig. 2. Radial section through the anterior end of the body, the wall with upper 

 and lower [ms') circular muscles, and the oral disk with a tentacle. Unscr. A, Oc. 2. 

 For I in the lettering of the plate read t. 



Fig. 3. Transverse section through the septum at about one-third the height of the 

 animal, passing perpendicularly through the parietobasilar muscle and longitudinal muscle. 

 A, Oc. 1. 



Fig. 4. Half a transverse section of the upper circular muscle. C, Oc. 1. 



Fig. 5. Septum ; natural size. 



Dysactis crassicornis (figs. G-12). 



Fig. G. Transverse section through a septum. A, Oc. 1. 



Fig. 7. Transverse section through the upper end of the wall. Unscr. A, Oc. 2 

 diminished two-thirds. 



Fig. 8. Part of a transverse section through the circular muscle, more highly mag- 

 nified. D, Oc. 1. 



Fio". 9. Section through the circular muscle parallel to the course of the fibriUse. 

 A, Oc. 2. 



Fig. 10. Transverse section through the oral disk of an old animal. Unscr. A, Oc. 2. 



Fig. 11. Transverse section through the oral disk of a young animal. Unscr. A, 



Oc. 2. 



Fig. 12. Septum ; natural size. The circular muscle appears rather too large in the 



drawing. 



