that Hagenow's division only embraces freely growing species it is founded on the 

 examination of a few badly conserved species of which only a single Escharites gra- 

 cilis with certainty can be referred to the Eleidœ, and as species belonging to this 

 division have never been found in the tertiary formation the following statement 

 of the author distinctly shows that his Salpingina also embraces common cyclosto- 

 matous species: »Alle sind fossil und gehören dem Jura, der Kreide und der Ter- 

 liärbildung an«. 



The presence of an operculum in the Salpingina should be a real diiîerence 

 from the Cyclostomata, but there is no evidence that the author has seen a real 

 operculum in any of the species referred by him to this division. As a species 

 provided with such an operculum he names Escharites ^FeliceaJ velata Hag., but this 

 species belongs to quite another division, the Ceidae, which are not provided with an 

 operculum, and what Hagenow has seen is only a closure-plate. 



d'Orbigny ') in 1852 founded a division to which he gives the name Centri- 

 fuginés operculinés and which he defines as follows: »Cellule centrifuginée toujours 

 pourvue d'un opercule. Colonie très variable dans sa forme composée de cellules 

 généralement peu saillantes, mais toujours pourvues d'un opercule : partie testacée 

 ou calcaire, s'ouvrant comme une porte pour laisser sortir l'animal«. As to the 

 operculum he later adds: D'ailleurs s'il pouvait encore rester quelques doutes à 

 cet égard la presence de ces opercules encore restés en place dans beaucoup d'es- 

 pèces fossiles, vient entièrement les lever et donner la preuve que cet opercule exi- 

 stait«. To this division d'Orbigny refers two families, the Eleidae and the Myrio- 

 zoumidae, the last of which contains the exstinct genus Foricula and the recent genus 

 Myriozonm. The last named genus, however, belongs to the Clieilostomata. The above 

 quotation leaves no doubt that d'Orbigny has founded his division Eleidae on the 

 presence of an operculum, and it is a curious fact that all the modern authors with 

 the exception of the present though accepting this division, at the same time deny 

 that its member possesses an operculum, explaining the calcareous plate which may 

 be found closing the aperture of more or less zooecia as a closure-plate. Not a 

 single author even mentions this statement of d'Orbigny. 



Hamm") in 1881, founded a very artificial division, the Sffg/nafoporma to which he 

 besides two inoperculate cyclostomatous genera Stigmatopora Hamm {-Hammia Grey) 

 and Cyrtopora Hag. also referred the operculate genus Meliceritites. He characterizes this 

 division as follows: »Die Zellen sind ähnlich wie die der Tubuliporiden beschaffen. Statt 

 dass sie aber in der mittleren Axe des Stammes entspringen legen sie sich rings um ein 

 senkrecht stehendes, im Querschnitt rundliches Bündel von langen cylindrischen unter 

 einander parallelen Röhren . He divides the Stigmatoporina in two groups the second of 

 which (^Me/icer(7z7esy he characterizes by the trumpet-shaped distal enlargement of the zo- 

 oecia: ». . zweitens in solche, deren Zellen lang, anfangs sehr dünn sind und erst an der 

 Mündung sich plötzlich trompetenförmig erweitern«. As we have seen Hagenow has al- 



') 7, p. 605. "-) 8, p. 45. 



