1312 THE VOYAGE OF H.M.S. CHALLENGER. 



Genus 580. Dicolocapsa, 1 Haeckel, 1881, Prodromus, p. 433 (sensu emendate). 



Definition. S ethocapsida (vel Dicyrtida eradiata clausa) with a free cephalis, 

 without apical horn. 



The genus Dicolocapsa differs from the preceding Sethocapsa in the loss of the 

 apical horn, and therefore bears to it the same relation that Dictyocephalus does to 

 Sethocyrtis. 



1. Dicolocapsa microcephala, n. sp. (PL 57, fig. 1). 



Shell smooth, thin-walled, with distinct collar stricture. Cephalis small, subspherical, with 

 small, crowded pores. Length of the two joints = 1:3, breadth = 1 : 3. Thorax also nearly spherical, 

 three times as large as the cephalis, with small, irregularly scattered, circular pores, and much 

 broader bars. 



Dimensions. Cephalis 0'03 diameter, thorax 0'09 diameter. 



Habitat. Western Tropical Pacific, Station 225, depth 4475 fathoms. 



2. Dicolocapsa megacephala, n. sp. 



Shell smooth, thin-walled, with sharp collar stricture. Cephalis large, conical, obtuse. Length 

 of the two joints = 5:9, breadth = 6 : 8. Thorax ovate, truncate, with hemispherical base. Pores 

 of both joints equal, subregular, circular, about as broad as the bars. 



Dimensions. Cephalis 0'05 long, O06 broad ; thorax - 09 long, O'OS broad. 



Habitat. Central Pacific, Station 272, depth 2600 fathoms. 



3. Dicolocapsa platycephala, n. sp. 



Shell papillate, thick-walled, with slight collar stricture. Cephalis flat, hemispherical, hyaline, 

 without pores (or with few small pores). Length of the two joints = 2 : 11, breadth = 4 : 9. Thorax 

 ovate, with small, regular, circular pores, half as broad as the bars. 



Dimensions.^Cephalis - 02 long, 0'04 broad ; thorax Oil long, 0'09 broad. 



Habitat. Fossil in Barbados. 



Genus 581. Cryptocapsa,' 2 Haeckel, 1881, Prodromus, p. 433. 



Definition. S ethocapsida (vel Dicyrtida eradiata clausa) with a cephalis 

 hidden in the thorax, without apical horn. 



1 Dicolocapsa = Two-jointed capsule ; 8/xaXof, xii-^a. 



2 Cryptocapsa = Hidden capsule ; xyjvro;, xxt^a. 



