PLATE 33. 
Hyalonema (Hyalonema) obtusum gracilis LENDENFELD. 
’ Figures 1-24. 
1, 2.— Centrotyle amphioxes; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6. 
3.— Group of small hypodermal amphioxes; magnified 100; phot. Zeiss, apochr. 16, compens. oc. 6. 
4.— Small hypodermal amphiox; magnified 300; phot. Zeiss, apochr. 4, compens. oc. 6. 
5-14.— Side-views of hypodermal pentactines; magnified 50; phot. Zeiss, achr. aa, compens. oc. 2. 
15.— View of the sponge; magnified 1.1; phot. Zeiss, anastig. 480/412 mm. 
16.— View of the sectioned face of the sponge cut in half longitudinally and axially; magnified 2; phot. 
Zeiss, anastig. 167 mm.: 
a, oral cone; b, lower end (place where the stalk is broken off). 
17.— The tip of a lateral ray of a hypodermal pentactine; magnified 300; phot. Zeiss, apochr. 4, compens. 
oc. 6. 
18-23.— Rhabds of the supporting skeleton; magnified 50; phot. Zeiss, achr. aa, compens. oc. 2: 
18, 19, small, slightly centrotyle amphioxes; 
20, tylostyle; 
21, medium centrotyle amphiox; 
22, medium amphiox; 
23, large amphiox. 
24.— Oblique apical view of a hypodermal pentactine; magnified 50; phot. Zeiss, achr. aa, compens. 
oc. 2. 
a 
