12 :\rr. A. W. Wator,so;i 



described, wlierras /. trijoriff has ovicells * enclosing; a scries. 

 This very remarkable ovii-ell has only been seen on oue 

 specimen, and it is to be hoped that others will turn up. 

 While the general characters are so closely similar, it would 

 be dirticult to place them in ditterent genera, on account of 

 the ovicells, and we must wait for further light on this 

 ])oint. 



There arc some small basal specimens, which, from the 

 size of the zocjceia and the distance apart of the series, are 

 no d()ul)t /. mcniu/hinii, in which the striated dorsal surface 

 lias over the lower part an overgrowth with elongated pores 

 (fig. 10), so that this part is like Crisina. 



Canut refers to a similar growth in Idmonea coronopus, 

 saying that the " canaux de renforcemeut " are liea})ed np 

 on the dorsal surface of the old zooeeia, and sometimes the 

 substratum is detached by fossilization. Smitt + speaks of 

 abortive zooeeia in /. atlantica^ and on that account hesitates 

 to accept the genus Crisina. Pergens § says that in Idmonea 

 carinata, Rss., a section of the upper part shows only four 

 canals de renforcenient, whereas there are about forty in 

 the lower ])art, Ilarmer 1|, speaking of/, atlanticn., says the 

 stalkof the colony becomes thickened by secondarily developed 

 calcareous tubes, the "canaux de renforcemeut" of Pergens, 

 and (page 126) he speaks of a secondary thickening which 

 grows in a distal direction, but does not extend far up the 

 colony. 1 have seen it beyond the second bifurcation. 



The two inner zooeeia of /. meneyhinii are ustialiy closely 

 attached and the otliers more separated, as in many species 

 of Idmonea, and therefore /. erecta, Calv., is considered a 

 svnonym. The measurements of the two are fairly similar. 



Loc. Naples, Capri, Nice, Cette, Marseilles, Lessina and 

 Lissa (Adriatic), i/e//.; between Fayal and Pico (Azores), 

 50-90 fath. (' Cliallenger'). 



Fossil. Italian Tertiaries. 



Idmonea triforis, Heller. (PI. II. fig. 1.) 



Idmonea triforis, Heller, Die Bryozoen des Adriat. p. 120 (18()7) ; 

 Busk, ]Jiit. Mus. Cat. pt. iii. p. 115 (1875); Waters, Bry. from the 



* " On some Ovicells of Cycl. Biy.," Joiirn. Liuu. Soc, Zool. vol. x.\. 

 pi. xiv. fig. 2 (1888). 



t "Bry. des Terr. Tert. des Environs de Paris," Ann. Palaeont. vol. ii. 

 p. 128. 



X Floridan Bry. pt. i. p. 7; Krit. Fort, of Vet.-Akad. p. 44 (18G6). 



§ " Rev. des Bry. du (Jr6tacee fig. par d'Orbigny," Bull. Soc. Oeol. de 

 Fr. p. 312. 



Ii ' Siboga' Exped.p. 138 (1920). 



