REPORT ON THE RADIOL ARIA. 1319 



10. Pterocorys melitta, Haeckel. 



Rhopalocanium ornatum, Bury, 1862, Polycystins of Barbados, Taf. vi. fig. 4. 



Shell slender, smooth, with two deep strictures. Length of the three joints = l : 1 : .3, 

 breadth = 1:2:2. Cephalis subspherical, with a pyramidal horn of twice the length. Thorax broad 

 and short, loaf-shaped, with three conical wings, which are horizontally expanded, and half as 

 long as the shell. Abdomen cylindrical, with wide, truncate mouth. Pores small, subregular, 

 circular. 



Dimensions. — Length of the three joints, a 0-025, h 0-03, c 0-09 ; breadth, a 0-0.3, h 0-06, c 0-06. 



Habitat. — Fossil in Barbados. 



11. Pte7'ocorys turgida, Haeckel. 



Lychnocanium turgidtim, Ehrenberg, 1885, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 80, 



Taf. vii. fig. 6. 



Shell thick -walled, pear-shaped, smooth, with sharp collar stricture. The lumbar stricture is 

 not distinct externally, but is represented by a broad, internal, annular septum. Length of the three' 

 joints =1 : 6 : 3, breadth = 2 : 7 : 6. Cephalis hemispherical, with a stout pyramidal horn of the 

 same length. Thorax and abdomen together pear-shaped, inflated. Immediately above the lumbar 

 stricture three stout, conical, lateral wings, as long as the cephalis, arise. Mouth very small, 

 about as broad as the cephalis. 



Dwnensions. — Length of the three joints, a 0-02, h 0-12, c 0-06 ; breadth, a 0-03, h 0-13, c 0-12. 



Habitat. — Fossil in Barbados. 



Subgenus 2. Pterosyringium, Haeckel. 



Definition. — Horn of the cephalis simple. Abdomen prolonged into a narrow 

 cylindrical tube. 



12. Pterocorys tuhulosa, n. sp. (PI. 68, fig. 6). 



Pterosyringium tuhulosum, Haeckel, 1879, Atlas, loc. cit. 



Shell thick-waUed, rough, with two slight strictures. Length of the three joints = 1:4:4, 

 breadth = 1:3:1. Cephalis hemispherical, with a conical horn of the same length. Thorax 

 ovate, in the upper half with three ribs, arising into short, triangular, slightly prominent wings. 

 Abdomen prolonged into a cylindi-ical, narrow tube of the same length as the thorax. Terminal 

 mouth very narrow. Pores subregular, circular. 



Dimensions. — Length of the three joints, a 0-03, h 0-12, c 0-12 ; breadth, a 0-03, b 0-09, c 003. 



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



