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

 pora, des Entalophora et une quantite 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 Clieilostoniatous avicu- 

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

 operculum. He says about that, referring to transverse sections o{ Meliceritites Roy ana: 

 »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'Orhigny's calcareous opercula, and, therefore, no doubt regards them in the same 

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

 inclined to think that the Eleida; are nearer related to the Clieilostomata than to 

 the Cyclostomata. 



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

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



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



2) Gregory (14, p. 285) wlien speaking about d'Orbigny's institution of the family £/cidachas quite 

 misunderstood this author. He says as follows: »D'Orbigny founded this family in 1853 for a 

 series of Bryozoa with anomalous characters, of which the most striking was the presence 

 of a series of modified zoiecia that he described as ^cellules accessoires<. These accessory 

 structures are of two types, large superficial marsupial chambers, and cells with triangular 

 or elongated apertures and a platform iiarallel to the surface of the zoarium. The marsupial 

 chambers were described by d'Orbigny as Dcellules ovariennes's and they are clearly gono- 

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

 that they sometimes occur on the same specimen as »cellules ovariennes«, and therefore 

 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 nuist understand 

 the above statement in that manner 1) that r/ORBioNv has founded the family Eleidae chiefly 

 on account of its possessing modified zooecia (licellules accessoiresi), and that he has only 

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

 sence of marsupial chambers (gonozoa?cia) in the Eleidae, and 3) that he has interpreted some 

 of the modified zotecia found in the Eleidae as „cellules males". As to the first ])ointthe above 

 quotation of d'Orbigny shows that he has founded tfie division Centrifitgines opcrciilincs not on 

 account of its [)Ossessing modified zooecia, but because it possessed calcareous opercula. and 

 for i)oth the families belonging to tliis 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 has nowhere mentioned or pictured an Eleid gonozosecium, and what he says 

 about , cellules m;tles" only concerns the Cheilostomata. The structure of the avicularia be- 

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

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

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

 held further by all his i)redccessors, and therefore he asks whether they may not liere be 

 regarded as DCellules m;iles«. In the representation he gives of the linjozoaires centrifutjines, 

 a division which besides some C<e;!0«/onia<a comprises the present Cyclostomata. the Eleidae, the 

 Myriozoumidae and the Ceidae, he says aliout tliese modified zooecia'-): Uans quelques genres 



7, p. 99. ■) 7, p. 587. 



