GENERA OF CH^ETETID^E AND MONTICULIPORID^. 307 



given pair of the former. The small tubes are closely tabulate, 

 but by the imperfect development of their walls the tabulae 

 coalesce to a larger or smaller extent, and thus give rise to a 

 vesicular tissue, composed of lenticular vesicles, which have their 

 convexities directed upwards. 



Fig. 39. Fistulipora minor, M'Coy. A, Portion of a tangential section, showing the rounded 

 large tubes (a, a) and the angular interstitial tubes (b, b); B, Portion of a vertical section, 

 showing two of the large tubes, almost free from tabulae (a, a), and the interstitial vesicular 

 tissue formed by the tabulae of the smaller tubes (b, b). The sections are enlarged twenty- 

 five times. 



Obs. I am indebted to my friend Dr Ramsay H. Traquair 

 for a specimen from the Carboniferous rocks of Scotland which 

 he had previously, and unquestionably correctly, identified with 

 the Fistulipora minor of M'Coy. The surface of this specimen 

 is poorly preserved, the prominent round mouths of the larger 

 tubes being alone shown ; and I am unable to determine 

 whether or not " maculae " are present, though I see no traces 

 of these in thin sections. The internal structure is fully shown 

 by thin tangential and vertical sections (fig. 39, A and B) ; but I 

 need add nothing further to the description given in the specific 

 diagnosis. 



In its minute characters, F. minor is nearly related to F. 

 incrassata, Nich., from the- Devonian of North America. This 



