1214 THE VOYAGE OF H.M.S. CHALLENGER. 



4. Lamprodiscus Icevis, Haeckel. 



Eucecryphalus laivis, R Hertwig, 1879, Organism, d. Radiol,, p. 77, Taf. viii. figs. 6, 6rt, 65. 



Shell smooth, with distinct collar stricture. Length of the two joints = 1:3, breadth = 1:6. 

 Cephalis subspherical, with small circular pores and an oblique conical horn of twice the length. 

 Thorax flat, pyramidal, twice as broad as long, with three strong, straight divergent edges and 

 subregular roundish pores. Peristome smooth. 



Dimensions. Cephalis 0'025 diameter; thorax 0'08 long, O16 broad. 



Habitat. Mediterranean (Messina), E. Hertwig, surface. 



Genus 542. Lampromitra, Haeckel, 1 1881, Prodromus, p. 431. 



Definition. S ethopilida (vel Dicyrtida triradiata aperta) with three divergent 

 lateral ribs in the wall of the flat conical or pyramidal thorax. Cephalis commonly 

 with a horn. Peristome with a corona of spines. 



The genus Lampromitra differs from the preceding and nearly allied Lamprodiscus 

 only in the development of a dentated peristome, or an elegant corona of teeth around 

 the wide open mouth. It bears therefore to the latter the same relation that 

 Clathrocorona does to Clathrocanium. 



1. Lampromitra coronata, n. sp. (PL 60, fig. 7, 7a). 



Shell flat, conical, with slight collar stricture. Length of the two joints = 1:2, breadth = 2:7. 

 Cephalis hemispherical, with a conical oblique horn of twice the length, and small subregular 

 hexagonal pores. Thorax with larger, subregular, hexagonal meshes, six to eight times as broad as 

 the bars. Peristome or basal margin of the thorax circular, with a marginal ring of smaller polygonal 

 meshes and a triple coronal of short spines ; two external rings of short conical centrifugal spines, 

 and an internal ring of thin centripetal rods (fig. 7 a). In fig. 7 the shell is seen from below and 

 exhibits very distinctly the internal cross of the collar septum, composed of the four divergent 

 cortinar bars ; between the latter descend the four pear-shaped lobes of the central capsule (each 

 containing an oil globule), whilst the apical part of the capsule (with the nucleus) is hidden in the 

 large cap-shaped cephalis. 



Dimensions. Cephalis 0'03 long, 0'07 broad ; thorax 0'06 long, 0'2 broad. 



Habitat. Central Pacific, Station 271, depth 2425 fathoms. 



2. Lampromitra quadricuspis (PL 58, fig. 7). 



Shell flat, conical, with sharp collar stricture. Length of the two joints =1 : 3, breadth = 2 : 10. 

 Cephalis hemispherical, with subregular circular pores and an oblique, conical, occipital horn of twice 



1 Larnpromitra= Splendid turban; 



