1(> IWONEID^i:. 



19. Idiuonea tuberosa, D'Orb. 



" Sleudei', everywhere wrinkled truiisvensely, brauolied, slightly 

 compressed ; rows indistinct, each consisting of two separate cells." 



Idmouea tuberosa, D'Orb. I. c. p. 7ol. 

 ■;' Idinonea mariouensis, Bk. 



Hah. He de Basilan. 



20. Idmonea canariensis, D'Orb. 



" Slender as a thread, almost round, with very few cells." 



Idmonea canariensis, D'Orb. I. c. p. 731. 

 ? Idmouea gracillima. BI;. 



Bab. Tencriffe (D'Orb.). 



21. Idmouea californica, D'Urlj. 



"Wide, much depressed, marked as if by steps of growth beneath, 

 presenting above simple transverse lines of cells not interrupted in 

 the middle." 



Idmouea californica, D'Orb. I. c. p. 7oI. 



IJab. He de Yenado, iler Yermeille, California (D'Orb.). 



22. Idmonea fenestrata, Busk. 



Zoarium irregularly reticulate ; branches anastomosing, subtri- 

 gonal, often angular behind ; mouths of cells projecting, quadran- 

 gular, 5-0 in each series ; cells flattened in front. Surface linelj' 

 punctate ; dorsal surface very finely reticulate, sulcate, with elon- 

 gated pores in the sulci. 



Idmonea fenestrata, Bk. Mo)i. Crmj Tolyzoa, p. 105, pi. xv. fig. 6 P ; 

 Smitt, SkandiH. Hofs-Bryuzoer, 18G6, p. 300. 



Hah. Spitzbergen, 50 fathoms (Malmijrcn). Fossil in the Coral- 

 line Crag. • 



The identification of this species with the Crag form has been 

 made by Prof. Smitt with some doubt. 



2. HORNERA, Lamx. 



Zoarium ramose, ramification irregularly dichotomous. Branches 

 cj'lindi'ical or subcompressed. Zoocecia opening only on one side of 

 the branch. Oocecia dorsal or anterior. 



Hornera, Lavix. Krposit. p. 41 (1821) ; Milne-Edwards (pars) ; Beiiss 

 (pars); Blahiville (pars); Def ranee, Michelin, Hagenow, D'Or- 

 hi(jny, Smitt, Busk, Sars, Alder, Norman, ^-c. 



Millepora (pars), Limi., Pallas, Esper, Solandcr. 



Retepora (pars), Lamk., OoMfK.ss. 



Siphodictyiun. L(in>ida!r. 



