UJ L I B R 



une membrane calcareuse transversale, caractère qu'elles partagent avec des Hetero- 

 pora, des Enlalophora et une quantité d'autres genres. — 



Waters') who was the first to point out the likeness between the »cellules 

 accessoires« or »cellules ovariennes« of d'Orbigny and the Cheilostomatous avicu- 

 laria is inclined to think, that the Eleidae have been provided with a chitinous 

 operculum. He says about that, referring to transverse seclions o( Meliceritites Royana: 

 »In transverse sections (figs 5 and 11) a contraction formed by a curved plate is 

 seen on each side just below the opening. Possibly an operculum has an attachment 

 here, but of this I have not been able to satisfy myself«. He does not mention 

 d'Orbigny's calcareous opercula, and, therefore, no doubt regards them in the same 

 way as the other authors, namelj' as closure-plates. On the whole Waters seems 

 inclined to think that the Eleidce are nearer related to the Cheilostomata than to 

 the Cijclostomata. 



Gregory^) who regards the Eleidae only as a family of his suborder Cyclosto- 

 mata tiibiilata defines this family as follows: »Cyclostomata tubulata in which the 



1) 12, p. 48, pi. VI. 



'-)riREGORY(14,p.2S5) when speaking about d'Orbigny's institution of the family EWdaehas quite 

 misunderstood this autiior. He says as follows: »D'Orbigny I'ouniicd this family in 1853 for a 

 series of Bryozoa with anomalous characters, of which the most striking was the ])resence 

 of a series of modified zoæcia that be described as »cellules accessoires«. These accessory 

 structures are of two types, large sui)erficial marsupial chambers, and cells with triangular 

 or elongated apertures and a platform i)arallel to the surface of the zoarium. The marsupial 

 chambers were described by d'Orbigny as »cellules ovariennes«, and they are clearly gono- 

 cysts or gonæcia. The nature of the second set is more important. D'Orbigny recognized 

 tliat they sometimes occur on the same specimen as »cellules ovariennes«, and tlierefore 

 cannot be ovarian. He suggested that they may be male cells or sperm-cells. Nevertheless 

 Pergens and Marsson subsequently described them as ovicells«. Every reader must understand 

 the above statement in that manner 1) that d'Orbigny has founded the family Eleidae chiefly 

 on account of its possessing modified zooecia (»cellules accessoires«), and that he has only 

 found such modified zooecia in the Eleidae. Further 2) that d'Orbigny has pointed out tlie pre- 

 sence of marsupial chambers (gonozoæcia) in the Eleidae, and 3) that lie has interpreted some 

 of the modified zoæcia found in the Eleidae as „cellules males". As to the first point the above 

 quotation of d'Orbigny shows that he has founded the division Centrifugines operciilinés not on 

 account of its possessing modified zooecia, but because it possessed calcareous opercula, and 

 for both tlie families belonging to this division he only mentions in somewhat different terms 

 that they sometimes possess »cellules accessoires« which structures, besides, he has found not 

 only in this division, but also in the Cheilostomata and the Cyclostomata. As to the two other 

 points d'Orbigny lias nowhere mentioned or pictured an Eleid gonozoæciuni, and what he says 

 about „cellules males" only concerns the Cheilostomata. The structure of tlie avicularia be- 

 ing at that time unknown d'Orbigny is evidently most inclined to look upon the modified zo- 

 oecia as gonozoæcia (»cellules ovariennes«), but as in Eschara') they are found togetlier with 

 zooecia wearing ooecia he cannot escape regarding the latter as »cellules ovariennes«, a view 

 held further by all his predecessors, and therefore he asks whether they may not here be 

 regarded as »cellules males«. In the representation he gives of the Bnjozoaires centrifugines, 

 a division which besides some Ctenostomata comprises tlie present Cyclostomata. the Eleidae, the 

 Myriozoumidae and the Ceidae, lie says about these modified zooecia-): Dans quelques genres 



') 7, p. 99. •-) 7, p. 587. 



