1378 THE VOYAGE OF H.M.S. CHALLENGER. 



six longitudinal rows of large, roundish, quadrangular meshes (four to five meshes in each row). 

 Mouth hexagonal. 



Dimensions. Length of the three joints, a 0'025, b 01, c 0'3 ; breadth, a 0'03, b 01, c 0'2. 



Habitat. Fossil in Barbados. 



6. Cycladophora spinosa, n. sp. 



Shell spiny, with two deep strictures. Length of the three joints = 1:4:3, breadth = 1:5:4. 

 Cephalis subspherical, with a stout conical horn of the same length. Thorax ovate, with regular, 

 circular pores, and numerous conical spines. Abdomen truncate, conical, with irregular, roundish 

 pores, and six strong, divergent ribs. Mouth circular. 



Dimensions. Length of the three joints, a 0'03, b 012, c 009 ; breadth, a 0'03, b 015, c 012. 



Habitat. Central Pacific, Station 268, depth 2900 fathoms ; fossil in Barbados. 



Subgenus 3. Lamptonium, Haeckel. 



Definition. Abdomen with nine radial ribs (three primary or perradial, and six 

 secondary or interradial). 



7. Cycladophora enneapleura, n. sp. 



Shell spiny, with two sharp strictures. Length of the three joints =1:5:3, breadth = 2:7:4. 

 Cephalis hemispherical, with a conical horn of twice the length. Thorax campanulate, with regular, 

 circular pores, and conical thorax. Abdomen cylindrical, with nine straight, parallel ribs, and 

 irregular, roundish pores. Mouth circular. (Similar to Clydadophora gigas, Ehrenberg, 1875, 

 loc. cit., Taf. xviii. fig. 1, but differing in the possession of nine abdominal ribs.) 



Dimensions. Length of the three joints, a 0'03, b 015, c 01 ; breadth, a 0'06, b 0'2, c 012. 



Habitat. South Pacific, Station 295, depth 1500 fathoms. 



8. Cycladophora nonagona, n. sp. 



Shell spiny, with two distinct strictures. Length of the three joints = 3 : 10 : 7, breadth = 

 2:9:8. Cephalis pear-shaped, with a stout pyramidal horn of the same length. Thorax pear- 

 shaped, with regular, circular pores, and conical horns, increasing in size towards the base. 

 Abdomen truncate, pyramidal, with nine straight, spinulate ribs, and nine even faces between 

 them, with irregular, roundish pores. Mouth nonagonal. 



Dimensions. Length of the three joints, a 0'06, b 0'2, c 014 ; breadth, a 0'05, b 018, c 016. 



Habitat. Fossil in Barbados. 



