PLATE IV. 
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. 
S 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. 
Fig. 1. Myzostoma Jissum, n. sp. 
Fig. 1. The animal seen from the dorsal side. 
Fig. 2. Myzostoma intermedium, n. sp. 
Fig. 2. Outline only. C the last pair of cirri ; CA 1 -CA 3 , the caudal appendages. 
Figs. 3-6. Myzostoma quadrifilum, n. sp. 
Figs. 3, 4. Two individuals, seen from the ventral side. 
Figs. 5, 6. Marginal cirri of another individual, more highly magnified ; seen from above 
(6), and from below (5). 
