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another. The present species agrees well, so far as I can judge, wïth the first of these three. 

 In the arrangement of its zooecia, in the form of its ovicells, and particularly in the characters 

 of its ooeciostomes, it resembles T. aperta Harmer l ), from which* it differs in the much smaller 

 size of the zooecia. The peristomes are slender and of great length, being mostly free in the 

 central parts of the colony and only united into series at the margin. The largest colony 

 (fig. 10) measures about 4.5 mm. in longest diameter. 



The roofs of the ovicells occur at the bases of the greatly elongated peristomes, and 

 thus appear to lie at a low level. The outlines of the ovicells cannot be distinguished clearly 

 in the specimen figured ; but their number is indicated by the ooeciostomes, of which three 

 are present. Each is a tube of some length, standing more or less at right angles to the 

 roof of its ovicell, and completely free from the zooecia. The ooeciostome becomes compressed 

 near its free end, so that the ooeciopore is elongated. The free lip of the ooeciostome is 

 slightly everted. 



350. D. and 351. E. were found on sea-weed; 352. 13. on what appears to be a 

 Chaetopod tube, perhaps a P hy llochaetopterus \ and 57. Y. on an Adcona (57. C). The last 

 specimen has rather coarser tubes, and more nearly approaches T. aperta in this respect. It 

 is possible that it does not belong to the same species as the specimens from Stat. 240, but 

 it has no more than the commencements of ovicells. 



Measurements, in y. : 



Greatest diameter of colony, fig. 10, 4,500; 

 Diameter of zooecia, 95 •, 

 Diameter of ooeciopore, 110. 



2. Tuèulipora atlantica (Forbes, MSS.) Johnston. (PI. X, figs 4, 5). 



Idmonea atlantica (Forbes, MSS.) Johnston, 1847, "Hist. Brit. Zooph.", Ed. 2, p. 27S, PI. XL VIII, 



figs 3. 3- 

 Idmonea atlantica Busk, 1856, "Pol. Norway and Finmark", Ann. Mag. Nat. Hist. (2) XVIII, 



p. 34, PI. I, figs 6a — e. 

 Idmonea atlantica Busk, 1S58, "Zoophytology", Q. J. Mier. Sci., VI, p. 128, PI. XVIII, fig. 5 



(Madeira). 

 Idmonea atlantica (pars) Busk, 1875, "Cat. Mar. Pol. Brit. Mus.", III, p. 11. 

 Idmonea atlantica Hincks, 1880, "Hist. Brit. Mar. Pol.", p. 451, PI. LXV, figs 1 — 4. 

 Idmonea atlantica (pars) Busk, 1886, 'Challenger' Rep., L, p. 10. 

 Idmonea atlantica Ortmann, 1889, "Japan. Bry.", Arch. f. Naturg., Jahrg. LVI, Bd I, p. 58, 



PI. IV, figs 20a, b (var. disticha Ortm.). 

 Idmonea atlantica Levinsen, 1894, "Zool. Danica", 4 Bd, 1 Afd., "Mosdyr", p. 76, PI. VII, figs 4, 5. 

 Idmonea atlantica (det. R. Kirkpatrick), Thurston, 1895, "Ramésvaram Island and Fauna G. 



Manaar", Madras Gov. Mus., Buil. 3, p. 131. 

 Idmonea atlantica Neviani, 1900, "Monogr. Gen. Idmonea", Parte I, pp. 6, 49 (synonymy); 



1901, Parte II, Cap. 2, p. 74. 

 Idmonea atlantica Jullien and Calvet, 1903, "Rés. Camp. Sci. Prince de Monaco", XXIII, p. 113. 

 Idmonea atlantica Waters, 1904, "Bry. Fr.-Josef Land", II, J. Linn. Soa, Zool., XXIX, p. 166, 



PI. XXI, figs 2, 3 (the ovicell here figured is unusually short). 



1) Harmer, S. I-"., 1898, "Dev. Tuiu/ipora", Quart. J. Mier. Sci., XLI, p. 101. 



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