1668 THE VOYAGE OF H.M.S. CHALLENGER. 



small Medusae (e.g., Codonium, Tiara, Sarsia, &c.). This similarity is the greater, as 

 usually the four feet are elegantly curved and the entrance in the shell-cavity partly 

 closed by a marginal diaphragm, comparable to the velum of the Craspedotae or 

 Hydromedusse. In all the species observed the apex of the shell bears a slender vertical 

 or Curved spine, comparable to the apical horn of the NASSELLARIA. In most 

 species the feet bear on their convex outside a series of teeth or branches, which are 

 also alveolate. 



1. Medusetta codonium, n. sp. (PL 120, fig. 1). 



Shell ovate, smooth, twice as broad as the constricted mouth. Apical horn about as long as the 

 shell, nearly straight, smooth. Feet cylindrical, smooth, irregularly curved, about as long as the 

 shell. 



Dimensions. Length of the shell 0'08, breadth 0'05. 



Habitat. Tropical Atlantic, Station 347, depth 2250 fathoms. 



2. Medusetta tiara, n. sp. 



Shell campanulate, smooth, about as long as broad, and three times as broad as the constricted 

 mouth, which is surrounded by a horizontal broad ring, like the velum of a Hydromedusa. Apical 

 horn conical, straight, half as long as the shell. Feet divergent, irregularly curved, twice as long 

 as the shell. 



Dimensions. Length of the shell 0'07, breadth 0'06. 



Habitat. North Atlantic (Fseroe Channel), John Murray, surface. 



3. Medusetta minima, n. sp. 



Shell slenderly ovate, smooth, about twice as long as broad, twice as broad as the constricted 

 mouth. Apical horn straight, vertical, of the same length. Feet somewhat longer, very thin, 

 slightly curved at the base, in the distal half nearly parallel and descending vertically. 



Dimensions. Length of the shell 0'06, breadth 0'03. 



Habitat. South Atlantic, Station 332, depth 2200 fathoms. 



4. Medusetta quadrigata, n. sp. (PL 120, fig. 2). 



Shell ovate, campanulate, smooth, little broader than the wide open mouth. Apical horn 

 longer than the shell, more or less curved, smooth. Feet cylindrical, about as long as the shell, 

 strongly curved and somewhat spirally revoluted, with a series of short curved teeth on the 

 abaxial margin. 



Dimensions. Length of the shell 0'07 to 0'09, breadth 0'04 to 0'06. 



Habitat. North Pacific (off Japan), Stations 231 to 237, surface. 



