1410 THE VOYAGE OF H.M.S. CHALLENGER. 



4. Theosyringium tubulus, Haeckel. 



Eucyrtidium tubulus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, 

 Taf. xi. fig. 6. 



Shell smooth, slenderly spindle-shaped, with two slight strictures. Length of the three joints = 

 2:10:8, breadth = 3 : 6 : 3. Cephalis hemispherical, hyaline, with a stout, pyramidal horn of 

 the same length. Thorax spindle-shaped. Abdomen inversely conical, half as long as the thorax 

 prolonged into a slender, cylindrical tube. Pores subregular, circular. 



Dimensions. Length of the three joints, a, 0'02, b 01, c Q'08 ; breadth, a 0'03, 1 0'06, c 0'03. 



Habitat. Fossil in Barbados. 



Genus 617. Lophocyrtis, 1 n. gen. 



Definition. T heocorida (vel Tricyrtida eradiata aperta) with cylindrical 

 abdomen, and wide open truncate mouth. Cephalis with two horns, or a bunch of 

 horns. 



The genus Lophocyrtis differs from its ancestral form Theocyrtis only in the 

 armature of the cephalis, bearing instead of a single horn either two divergent 

 horns, or a bunch, or coronal of numerous spines. The slender abdomen is in both 

 genera cylindrical, with wide open mouth. 



1. Lophocyrtis holothuria, n. sp. 



Shell smooth, slender, with two distinct strictures. Length of the three joints = 1:2:4, 

 breadth = 2:4:3. Cephalis hemispherical, with a bunch of five divergent, conical horns, the 

 middle of which is larger and vertical, nearly as long as the thorax. Thorax campanulate, half as 

 long as the cylindrical abdomen. Mouth truncate. Pores regular, circular, quincuncial. (Similar 

 to Theocyrtis cylindrica, but with different cephalis and thorax.) 



Dimensions. Length of the three joints, a O'OS, b OD5, c 01 ; breadth, a 0'04, b 0'07, c 0'06. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms. 



2. Lophocyrtis stephanophora, Haeckel. 



Eucyrtidium stephanophorum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, 

 Taf. viii. fig. 14. 



Shell smooth, slender, with deep collar and indistinct lumbar stricture. Length of the three 

 joints = 1:2:4, breadth = 1:3:3. Cephalis subspherical, with very small circular pores, and a 

 corona of three to nine short conical spines. Thorax campanulate, with regular, circular pores, 

 which are half or one-third as broad as those of the cylindrical abdomen. 



Dimensions. Length of the three joints, a 0-025, b 0'05, c 0'09 ; breadth, a 0'025, b 0'06, c 0'06. 



Habitat. Fossil in Barbados. 



1 Lophocyrtis =Za,sket \rith a crest ; 



