140 keport— 1884. 



produced cells are tubular, occasionally passing off into the Lepralia- 

 like form of a cell. The general features are that of Idmonea, but the 

 cell characters are abnormal, and one would incline to place the one form 

 in two different genera. The same feature is noticeable in some of the 

 cells of TercbeJlaria. Mr. Busk, in remarking on I. fenestrates (' Crag 

 Poly.' p. 105), says that his species approaches 'in some respects the I. 

 triquetra, Lamx., as well as a recent species met with in South Africa, 

 which, if not identical with the Caen fossil, is undistinguishable from it.' 

 The form referred to by Busk is before me, and there is certainly a like- 

 ness between the Jurassic and the Recent form, but the Recent form has 

 the advantage of being more highly specialised and also larger in both 

 the cells and in the size of the zoarium. Mr. Busk, however, says that 

 the branches of I. triquetra are very much thicker than the Recent form. 

 This difference of opinion may arise from difference in size of fragments, 

 but anyhow I cannot regard the 7. fenestrata, Busk, or the I. fenestrate/. 

 (Busk), Smitt, ' Scanct. Bryozoa,' as being one and the same species. This 

 being the earliest record that I have of Idmonea, I think it would be 

 unwise not to keep the species separate. It will be well, however, if 

 students will direct their attention to the several features referred to. 



Goldfuss, in his ' Petrefacta,' describes and figures what he gives as 

 five species of Retepora — R. cancellata, G. ; R. clathrata, G., and R. 

 lichenoides, G. ; R. truncata and R. disticha — all from the Chalk. It is 

 very evident that Goldfuss neglected to sort out his species, and the 

 consequence is that we have an assemblage of forms anything but satis- 

 factory ; consequently the labour of Hagenow on the group is all the 

 more appreciable, because he worked from fresh material, and, from 

 what I understand from his text, with full access to the type species of 

 Goldfuss. I also have been able to stndy the Faxoe Limestone material, 

 already referred to ; and if I offer any remarks upon the species of 

 Hagenow, it must be understood that I do so with specimens before me 

 which seem to be the same or of near the same horizon as those of 

 Hagenow's Maestricht beds. To prevent a repetition of Hagenow's and 

 Goldfuss's works, I shall give the reference to the plate and fig. only of 

 the two authors. 



•20. Idmonea MACULATA, Hag., H. Tab. IT., fig. 3. 



27. Idmonea clathrata, Goldfuss (Retepora), H. Tab. IT. fig. 2 



Gold., ' Pet.' Tab. IX. figs. 1-2 c and d. 



28. Idmonea yerrictlata, Goldfuss (Retepora), H. Tab. II. fig. 5 



Gold., 'Pet.' Tab. XXXVI. fig. 19 b. 

 20. Idmonea lichenoides, Goldfuss (Retepora), H. Tab. II. fig. 6 

 Gold., 'Pet.' Tab. XXXVI, fig. 13 a and b. 



30. Idmonea cancellata, Goldfuss (Retepora), H. Tab. II. fig. 7 = 



Idmonea ibid., Rss. 



31. Idmonea mactlenta, Hag. (Retepora), H. Tab. II. fig. 4. 



o2. Idmonea disticha, Goldf. (Retepora), H. Tab. II. fig. 8 ; Goldf., 

 ' Pet.' Tab. IX. tigs. 15 c, d = Retepora ibid., Goldf., Lamx., 

 Blainv. = ? Retepora, Michelin, Reuss. 



33. Idmonea pseudo-disticha, Hag., H. Tab. II. fig. 9 ; Gold. ' Pet.' 



Tab. IX. fig. 15 a-b = Ii. disticha, G., in part. 



34. Idmonea dopsata, Hag., H. Tab. II. fig. 10 ; Goldf., 'Pet.' Tab. IX. 



figs. 15 g & n = Retepora disticha, G., in part. 



35. Idmonea geometrica, Hag., H. Tab. II. fig. 11. 



36. Idmonea sulcata, „ „ ,, 12. 



