REPORT ON THE RA.DIOLARIA. 1205 



truncate, of about the same size. Both joints with very small and numerous pores, as broad as 

 the bars. Three feet arising from the middle part of the thorax, very small, rudimentary, 

 pyramidal, about as long as broad. Mouth truncate, little constricted. 



Dimensions. — Cephalis 0-05 long, 004 broad ; thorax 0-04 long, 0-05 broad. 



Habitat. — Fossil in Barbados. 



5. Lithomelissa pycnoptera, n. s\). 



Shell rough, papillate, with slight collar stricture. Eelative length of the two joints = 1:3, 

 breadth = 1:3. Cephalis small, hemispherical, with very small pores and a slender, straight, conical 

 horn of twice the length. Thorax subconical, with regvdar circular, hexagonally framed pores, as 

 broad as the bars. From its lower half arise three divergent, very strong feet, pyramidal, as long 

 as the thorax, and three times as long as broad. 



Dimensions. — Cephalis 0'03 diameter, thorax 01 diameter. 



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



6. Lithomelissa microstoma, n. sp. 



Shell papillate, with slight collar stricture. Pielative length of the two joints =1:5, breadth =1:5. 

 Cephalis small, hemispherical, with a conical horn of twice the length. Thorax subspherical, with 

 subregular circular pores, three times as broad as the bars. From its middle part arise three 

 divergent, stout, conical feet, of half the length, and twice as long as broad. Mouth small, strongly 

 constricted, one-fourth to one-third as broad as the thorax. 



Dimensions. — Cephalis 0'03 long, 0'04 broad ; thorax 015 diameter. 



Habitat. — Fossil in Barbados. 



7. Lithomelissa amphora, Stohr. 



Lithomelissa amphora, Stohr, 1880, Palseontograph, vol. xxvi. p. 100, Taf. iii. fig. 11. 



Shell smooth, with sharp collar stricture. Eelative length of the two joints = 1:5, breadth = 2:4. 

 Cephalis small, hemispherical, with a cervical horn of the same length. Thorax ovate, with small 

 regular circular pores, twice as broad as the bars. From its upper half arise three divergent, slender, 

 conical feet, only one-fourth as long. Mouth constricted, with a hyaUne peristome, half as broad as 

 the thorax. 



Dimensions. — Cephalis 0013 long, 0'026 broad; thorax 0'063 long, 0'053 broad. 



Habitat. — Fossil in tertiary rocks of Sicily ; Grotte (Stohr). 



Subgenu.s 2. Micromelissa, Haeckel, 1881, Prodromus, p. 433 {sensu emendato). 



Definition. — Cephalis with two divergent horns, a superior occipital horn and an 

 inferior frontal horn. 



