PLATE XII. 
In all the Plates the following letters have the same signification. 
c. Marginal cirrus. 
cl. Cloacal papilla or opening. 
i. Intestine. 
m. Mouth. 
ma. Manubrium of the supporting stalk of the hook-apparatus. 
ov. Ovarium. 
p. Parapodium. 
ph. Pharynx. 
s. Sucker. 
t. Testicle. 
u. Hook of the hook-apparatus. 
6 Male genital papilla or opening. 
Note . — The coloured drawings show the object seven times magnified ; the uncoloured drawings are drawn with the 
Oberhauser camera and objective 0 (Seibert and Krafft), which magnifies 40 diameters, the hook-apparatus with camera and 
objective IV., which magnifies 220 diameters, if the contrary be not expressly stated. 
Figs. 1-9. Myzostoma deformator, n. sp. 
Fig. 1. The animal, magnified 5 diameters ; seen from the dorsal side (A), and from the 
ventral side ( B ). 
Figs. 2, 3. A swollen pinnule of Pentacrinus alternicirrus, P. H. C., from both sides. 
The arrow shows the direction of the internal septum ; # is the injured 
pinnule lying opposite to the malformed one. 
Figs. 4-6. Another malformed pinnule of Pentacrinus alternicirrus , P. H. C., from both 
sides, and broken open (5) to show the septum. Here also the three 
arm -joints a-c share in the swelling. 
Fig. 7. A cross section through the Myzostoma in the hinder half of the body. 
Fig. 8. A cross section about the middle of the body (camera, objective 0). dvm., dorso- 
ventral muscular bundles ; e., epithelium of the surface of the body ; me., 
musculus centralis of the hook- apparatus ; n., brain ; %, nerves cut across ; 
od., oviduct; st., middle intestine (“stomach”). 
Fig. 
9. Isolated eggs of the ovarium, a, unripe, b, ripe ones (camera, objective IV.). 
