208 Canon A. M. Norman on 



Genus Teeebripora, d'Orbigny. 



This interesting genus, the exact position of which cannot 

 be determined until the animal shall have been examined, 

 but which is presumed to be a burrowing Polyzoon, was 

 instituted by d'Orbigny in 1841 * to include two species, 

 Terehriporn ramosa and T. irregularis, which he had found 

 in shells ot Calyptroia, Crepidula, and Pecten off the South- 

 American coast. 



In 1865 Paul Fischer published an excellent paper on the 

 fiimily t, in whicli he enumerates all the species both recent and 

 fossil presumed to be referable to his " Famille des Terdbri- 

 porides." In this paper eight recent and fourteen fossil species 

 are recorded. Two of the recent species had been found in 

 European seas — one, Terehripora Orbigniana^ Fischer, bur- 

 rowing in shells of Ostrea edulis at Arcachon, and in Gonus 

 mediterraneus and Triton nodifer in the Mediterranean ; the 

 other, Spathipora sertum, Fischer, found at La Rochelle, 

 Arcachon, and the Mediterranean in shells of Lutraria ellip- 

 tica, Cardium tiorvgicuin, Pectuncidus glycimeris, and Triton 

 nodifer. In 1880 M. J. Jullien \ added another recent 

 species, T. Fischeri, which was found in a shell of Buccinum 

 from Cape Verd Islands. 



Terehripora ditrupce, sp. n. (PL IX. figs. 4-7.) 



Terehripora has a mode of growth analogous to that of 

 Hippothoa divaricata, but instead of running over tlie surface 

 of shells &c. as in the latter species, the whole polyzoary is 

 buried in its substance, except that the orifices of the zocecia 

 open through the surface. The thread-like connecting fibres 

 or stolons in all species hitherto described appear to be quite 

 simple, but in T. ditrupce they consist of lines interrupted on 

 one side by small lateral projecting processes (tig. 5). The 

 zocecia are not in the same plane as tlie connecting fibre, but 

 at right angles to it, in such a manner that they are also 

 ])erpendicular to the surface (tig. 6). Owing to this position 

 of the zocecia their lower portion is too deeply seated to be 

 seen with the microscope; the oral opening has a somewhat 



* d'Orbigny (A.), 'Voyage dans I'AuKSrique m^ridionale,' vol. vi. p. 23, 

 pi. X. 



t Fischer (P.), " £tude sur les Bryozoaires perforant de la Famille des 

 T^rebriporides," Nouv. Arch, du Museum, vol. ii. pp. 293- ol3, pi. xi. 



\ Juliieu (J.), " Desc. nouv, Espece de Bryozoaire perforant du genre 

 Tvrebripora, d'Orbigny," BiUl. Soc. Zool. de France, 1880, pp. 1-i and 

 woodcut (separate copy). 



