IDMONEID.E. 105 



Polyzoarium ramose or fenestrate; branches subcylindrical ; mouths of cells small, 

 orbicular, prominent, 3 4 in each series ; surface, both anterior and posterior, uniformly 

 punctured. 



LATEKOCAVA PUXCTATA (?), D'OrLigny, pi. Dcclxxii, figs. 11, 12. 

 Habitat. C. Crag, S. Wood; Cretaceous (?), D' Orbigny. 



2. I. FENESTRATA (. sp.) PI. XV, fig. 6. 



Polyzoario irregulariter fenestrato vel reticulato ; ramis subtrigonis non raro postice 

 angulatis. Cellularum orificiis quadrangularibus, pronrinentibus, 5 6 singulis in seriebus. 

 Superficie anteriori cellularum planata delicatule maculata ; posteriori minute reticulata, 

 sulcata, porisque elongatis oruata. 



Polyzoarium irregularly fenestrate or reticulated ; branches subtrigonal, often angular 

 behind ; mouths of cells projecting quadrangular, 5 6 in each series ; front of tubes 

 flattened, surface finely dotted ; dorsal surface very finely reticulate, sulcate, with elongated 

 pores. 



Habitat. C. Crag, S. Wood, J. S. B. 



Approaching in some respects the Idmonea triquetra of Lamouroux, as well as a 

 recent species met with in South Africa, which if not identical with the Caen Fossil is 

 undistinguishable from it without direct comparison, the present species not only in habit 

 but in other particulars also appears to differ so materially from either, as to justify its 

 distinction from them. 



In /. triquetra (including the recent form above alluded to under that title) the front 

 of the branches is acutely angular, whilst in /. fenestrata it is rather rounded than 

 angular. The front of the tubular cells also in I. triquetra, though scarcely convex, is not 

 nearly so much flattened as in /. fenestrata ; nor is the dorsal surface in /. triquetra 

 pitted like that of I. fenestrata, being either smooth or very finely sulcate. But a more 

 obvious distinction exists in the general habit of the polyzoarium. In /. triquetra the 

 branches are very much thicker and curiously curved, as is well shown in Lamouroux's 

 figure, and in no specimen of the recent form, in fragments whose aspect precisely 

 resembles that of Idmonea triquetra, do the branches ever anastomose so as to constitute 

 the elongated elliptical meshes of I. fenestrata. 



There does not appear to be any other fossil Idmonea with which the present species 

 is likely to be confounded, unless perhaps it might be with I. maculata, Hag. (' Maastr. 

 Kreideb.,' pi. ii, fig. 3). The resemblance, however, is only in general habit, which is 

 certainly somewhat alike ; but in /. maculata the cells are said to be 3 5 serial ; and the 

 anterior angle of the branches appears to be carinate, whilst the dorsal is described as 



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