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The names on the Plates do not, however, agree completely with those used in the text. 



It should be noted that the three species retained in Crisina in the "Paleontologie 

 Frangaise" have porous backs, and thus agree with the definition of Crisina given in that work. 

 Of the others (as shown by the figures) I. unipora has no pores on its basal surface; and it 

 is stated in the text (p. 736) that the appearance of pores in that position in I. ramosa is due 

 to the fact that the specimens are worn. 



Gregory further objects (p. 160) that on PI. 614 of the larger work D'Orbigny figures 

 three species marked as Crisina, and that of these C. cenomana shows pores on the basal 

 surface. But D'Orbigny expressly states in his text (p. 733) that the appearance of these pores 

 is due to wear. C. cenomana (p. 732) was accordingly placed by D'Orbigny in Idmonea, to 

 which genus the second species, C. snbgracilis, a form with an imperforate back (p. 738), was 

 also referred. The only species left on this Plate is there called Crisina Ligeriensis, which is 

 treated in the text as a synonym of C. triangularis . Gregory's statement that C. cenomana is 

 "the only species amongst those originally included in Crisina which is available as a member 

 "of that genus" is invalidated by the fact that in the "Prodrome" (Vol. II, p. 175) C. cenomana 

 is referred to Crisisina, and not to Crisina. I have indicated above that Crisina as used in 

 the "Prodrome" appears to be a nomen nudum; but even if its validity in that work is 

 admitted, it may be pointed out that three of the five species originally included in it are 

 retained by D'Orbigny in Crisina in his larger work; in which, in fact, he rejects Crisisina 

 but retains Crisina. 



Gregory uses Crisina (p. 160) for the erect species which most writers on recent Polyzoa 

 refer to Idmonea. The above considerations appear to show that this procedure is inadmissible; 

 though it would have been open to him to have used Crisisina in the sense in which he 

 actually used Crisina. 



The peculiarities of the recent "Idmonea" radians appear to be sufficiently marked to 

 justify its separation from most of the recent species of " Idmonea\ and as it agrees exactly, in 

 its porous basal surface, with the feature emphasised by D'Orbigny in defining Crisina, there 

 seems to be every reason for placing it in that genus. The basal surface of C. radians has 

 the closest resemblance to that of C. triangularis, as shown by D'Orbigny in his PI. 769, 

 fig. 13. As I show below, in my account of C. radians, this feature is pronounced from the 

 earliest stages in the °Towth of the branches, and thus differs from the arrangement found in 

 other species here described (cf. Tubulipora atlantica, p. 126), in which the stalk of the colony 

 becomes thickened by secondarily developed calcareous tubes, the "canaux de renforcement" 

 of Pergens. 



I cannot find sufficiënt evidence of the characters of the ovicells of fossil species which 

 fall within Crisina in D'Orbigny's sense. MacGillivray l ) has described the ovicell of a Tertiary 

 Victorian form referred by him to C hocJistcitcriana Stoliczka, as being dorsal in position. 

 Waters 2 ), who regards Stoliczka's species as identical with C. radians, considers that the 

 form described by MacGillivray is Horncra fissnrata Busk. I am not quite convinced that this 



1) MacGillivray, P. IL, 1895, "Monogr. Tert. Pol. Vict.", Trans. R. Soc. Vict. IV, p. 121, PI. XVI, fig. 14. 



2) WATERS, A. W., 1914, "Mar. Fauna Brit. E. Afr.", "Biy. Cycl.", 1'roc. Zool. Soc, p. 845. 



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