REPORT ON THE RADIOLARIA. 1333 



13. Pterocanium trilohum, Ilacckel. 



Didijiqiddiinn trilohum, Haockel, 1882, Muiiogr. tl. Radiol, p. 340, Taf. viii. figs. G-10. 



Shell tliree-sided pyramidal, nearly tetraliedral, covered with conical spines. Length of the 

 three joints = 1:4:2, breadth = 1:6:10. Cephalis hemispherical, with a large conical horn (as 

 long as the thorax). Thorax tetrahedral, with little prominent crests. Abdomen forming three 

 semicircular, convex lobes between the three feet, half as long as the thorax, with the same irregular, 

 roundish pores. Feet slender, about as long as the shell, triangular, with convex back, strongly 

 divergent, fenestrated at the inflated and thickened base. (Compare the special description of the 

 living form and its soft body in my Monograph.) 



Dimensions. — Length (if the three joints, n 0-02, // 0-OS, c 004 ; breadth, a 0-03, h 012, c 0-2. 



Ualiitat. — ]\Iediterranean, Messina, surface. 



Geuus 589. Ptcrocodon,^ Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. 



Wiss. Berlin, p. 54. 



Definition. — Tlieopilida (vel Tricyrtida triradiata aperta) with three solid 

 free lateral wings on the thorax, and numerous solid terminal feet around the mouth 

 of the abdomen. 



The genus Ptcrocodon difiers from the closely allied Pterocorys, its ancestral form, 

 in the development of numerous solid feet around the terminal mouth, similar to the 

 terminal corona of Calocyclas. 



1. Ptcrocodon campanci, Ehrenberg. 



Pterocodon campana, Ehrenberg, 18.3-J-, Mikrogeol., Taf. xxxvi. fig. 10. 



Pterocodon campana, Elirenberg, 1875, Abbandl. d. k. Akad. d. "Wiss. Berlin, p. 82, Taf. xix. fig. 1. 



Shell slender, campauulate, subconical, with two distinct strictures. I,ength of the three joints 

 = 1:2:4, breadth = 2:3:5. Cephalis hemispherical, with a conical hum of twice the length. 

 Thorax hemispherical, in the upper part with three divergent, conical horns, as long as the cephalis, 

 and curved downwards. Abdomen with four transverse rows of large circular pores, increasing in 

 size towards the mouth ; the largest (undermost), five times as broad as the circular thoracic pores. 

 Mouth not constricted, with a corona of twelve to fifteen divergent, conical feet. 



Dimensions. — Length of the three joints, a O'Olo, h O'OS, c 006 ; breadth, a 0-02, h O'OS, c O'OS. 



Habitat. — Fossil in Barbados. 



2. Pterocodon ornatus, n. sp. (PI. 70, fig. 11). 



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

 = 1:5:7. Cephalis hemispherical, with a large oblique horn reaching half the length of the 



' Pterocodon = Bell with wings ; tts^o'v, y.ulut. 



