116 



G. LINDSTRÖM, HELIOLITID^. 



youngest mutation of this species, the ca- 

 licles of the largest; nat. size. 

 Fig. 18. Surface of a specimen from the Devonian 

 beds of the »Alpi carniche», Italy, kindly 

 communicated by Dr G. de Angelis 

 d'Ossat in Rome. ^/i- 



» 19. Surface, nat. size, of a large polypary from 

 the stratum d near Wisby, with narrow 

 tubular calicles, large columella and convex 

 tabulse. 



» 20. The same, magnified "/i, columella twisted 

 and branching, the lowest calicle at the 

 right partly overgrown by coenenchyma. 



» 21. Two calicles from the same specimen as in 

 figures 19 — 20, being invaded and over- 

 grown by coenenchyma; the columella is 

 still visible in the left one. ^ji. 



■fl 22. Longitudinal section of the same specimen, 

 showing a peculiar manner of growth; a 

 new polypary haviug extended sideways 

 and caused the extiuction of the older 

 subjacent by covering it. In the large 

 calicinal tube at the left side, in the centre 

 a broad columella has been sectioned, 

 showing a cuspidate crest. At the top of 

 the same tube may be seen a curious 

 accumulation of densely packed tabulse, a 

 Ijhenomenon also observed in other sec- 

 tions, probably due to an abnormous or 

 pathological secretion, causing the destruc- 

 tion of the polyp. Vi- 



» 23. Another section of the same, showing irre- 

 guliarities in growth through the condensa- 

 tion of the tabulie. The dark oblique lines 

 below are caused by accidental cracks, 

 causing a partial displacement of the tubes. 

 Columellar streaks and besides small aculse 

 on the tabulfe. Thecae of the calicinal 

 tubes sinuous. Vi- 



» 24. Transverse section lower down. The calicles 

 have the »decipiens» facies. The shaded 

 parts of the tubes are due to the hori- 

 zontal tabulse of the coenenchyma being 

 sectioned. ^Ii. 



Fig. 25, 26, 27. Three different, incipient polyparies 

 affixed to brachiopoda. Coenenchyma scanty 

 on the lower side of primary polypicrite. 

 All from the stratum d of Wisby. Vi- 



» 28. Longitudinal section of another incipient 

 polypary Vi- Same locality. The coenen- 

 chyma has begun on the right side of the 

 first polypierite and the second calicle has 

 budded from it. 



>> 29. Longitudinal section of a calicle, from the 

 stratum d, to show incipient or broken 

 tabulfe forming a sort of septal grooves at 

 their point of contact with the septa. Vi- 



? 30. Transverse section of a primary polypierite, 

 one millimeter above its apex, showing 

 three small septa on the right side, traces 

 of tabute; no coenenchyma. Vi- 



> 31. Longitudinal section of a small polypary, 

 showing the irregular manner of over- 

 growing older polypierites. Initial poly- 

 pierite to the right. In the larger central 

 calicinal tube there is a series of three 

 longitudinal, interrupted streaks, fragments 

 of septa, as the tube has been cut near 

 the theca, not centrally. ''/i. 



» 32. A series of sections I — iv from the same 

 calicle showing its gradual development 

 out of the coenenchyma beginning at I. 

 Section II contains two stages. i**/i. 



» 33. Longitudinal section of another calicle, same 

 specimen to show how the coenenchyma is 

 broken up when the gemmation sets in. 'V*- 



» 34. A series of sections I — IV to show the intra- 

 calicinal gemmation, beginning at I. */i. 



» 35. Two instances of intra-calycinal gemmation; 

 iu the left one a new calicle has grown 

 out of the coenenchyma of the older. Vi- 



» 36. Section, longitudinal of a calicinal tube, 

 being overgrown with ceenenchyma. There 

 is in the middle a curious funnel on the 

 lower side of which five small globular 

 bodies are fixed, and two below which seem 

 to have fallen down on the uppermost 

 tabula. Parasites? O va? "/i. 



