1196 THE VOYAGE OF H.M.S. CHALLENGER. 



pyramidal, with three strongly divergent ribs, which are prolonged into three slender conical feet of 

 about the same length. Pores irregular, roundish, of variable size. 



Dimensions. Cephalis 0'032 long, 0'028 broad ; thorax 0'34 long, 0'064 broad. 



Habitat. Mediterranean (Messina), Atlantic (Canary Islands), surface. 



3. Dictyophimus plectaniscus, n. sp. (PL 61, figs. 8, 9). 



Shell flat, pyramidal, smooth, with distinct collar stricture. Cephalis hemispherical, with a 

 conical horn of the same length and numerous small regular pores. Thorax flat, triangular, 

 pyramidal, with three widely divergent ribs, which are prolonged into three cylindrical feet of the 

 same length. Thoracic pores fifteen, very large, subregular, roundish, disposed in two transverse 

 girdles, the inner with six, the outer with nine pores ; five pores between every two ribs. 



Dimensions. Cephalis 0'04 long, 0'06 broad ; thorax 0'08 long, 018 broad. 



Habitat. Central Pacific, Station 265, depth 2900 fathoms. 



4. Dictyophimus craticula, Ehrenberg. 



Dictyophimus craticula, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, 



Taf. v. figs. 4, 5. 

 Dictyophimus craticula, Butschli, 1882, Zeitschr. f. Wiss. Zool., vol. xxxvi. p. 515, Taf. xxxiii. 



fig. 35. 



Shell flat, pyramidal, very similar to the preceding species, but differing in the rudimentary horn, 

 which is smaller than half the cephalis, and in the length of the three cylindrical feet, which are 

 twice to three times as long as the shell. The nine inferior large pores of the thorax are twice to 

 three times as large as the six superior pores. The basal peristome is commonly thorny. 

 Dimensions. Cephalis 0'04 long, 0'05 broad ; thorax 01 long, 0'2 broad. 

 Habitat. Fossil in Barbados. 



5. Dictyophimus pyramis, n. sp. (PI. 61, fig. 16). 



Shell regular, pyramidal, with flat collar stricture. Eelative length of the two joints = 1:4, 

 breadth = 2 : 6. Cephalis hemispherical, with a stout pyramidal horn of the same length. Thorax 

 triangular pyramidal, with three prominent ribs, which are prolonged into three slender pyramidal 

 feet, half as long. Pores small and very numerous, subregular, circular. 



Dimensions. Cephalis 0'03 long, 0'05 broad ; thorax 01 long, 015 broad. 



Habitat. Central Pacific, Station 266, depth 2750 fathoms. 



6. Dictyophimus challengeri, Haeckel. 



Dictyophimus challengeri, Haeckel, 1878, Protistenreicfi, p. 47, fig. 35. 



Shell campanulate, with sharp collar stricture. Eelative length of the joints = 1 : 3, breadth 

 = 1:4. Cephalis subspherical, with a stout pyramidal horn of twice the length, and numerous 



