374 CUMINGS AND GALLOWAY MORrilOLOGV OF TRErOSTOMATA 



I'LATE 15. — Morphology of the TuKrusroMATA. 



FiGUKEfs Til AMD 't'2. - Ldiu/i 1 11(1 i iKiJ sccHdiix of I hc >< u [ic rficiiil rcnioii of a xiteOt- 



irrii of ]>rlfi!ii(i iiiticiihihi. 



Tlic overgrowth thai has in'cscrv cd (lie (h-licalc s]iiiH' s has been 

 delincatod in detail in figure HI. At / the em! of the spine has 

 probably iieeu crushed, thoujxh there may have originally been 

 som(> special organ there. 'I'he submerged portion of the spiue 

 is shown al *'. figure 51. In figure 52 the spine was embedded 

 in fine sill, which is not shown in the drawing. The rounded 

 projections at a and a' show the ai)pearance wliicli acauthopores 

 present in ordinary longitudinal sections. X 65. (iG6-S, 9.) 



Figure 53. — Loiinilndinnl nccHon of a porlioii, of <t spine in the nyion s of 

 fifinrcs 51 and 52. 



The wall is very finely laminate and the lumen distinct. X "100.. 

 (16(>-10.) ■ 



Figure iJi.-^Longitudinal section of a spine at the level s', finiire 52. 



The inner fascicle of laminae is the primary wall of the acan- 

 thopore. The fascicles of lamina? outside of this are secondary 

 deposits, probably laid on by the surrounding zooecia. X 287. 

 ( 166-10. ) 



Figure 55. — Longitudinal f^ectio:! of the wall of Moulienlipora epidenvata. 



This shows a fairly distinct median dark zoi:e, as in the lute- 

 grata. X 287. (56-22.) 



Figure 50. — Hallopora splendens. 



The growing edge of the wall, intact because of the protection 

 of an overgrowth. The edge is very thin and the wall lamiuie 

 have a very steep pitch. X 287. (230-8.) 



Figure 57. — Similar section of the yroii-iiig edge of the icall of Dekagia 

 maeulata. 



The edge of the wall is very smoothly rounded and the laminte 

 run across without interruption from zooecium to zooecium. x 287. 

 (145-9.) 



Figure 58. — Section of the ivall of Stigmatella spinosa where it emerges from 

 the axial region. 



The median dark zone seen at a.r disappears completely farther 

 in toward the axial region of the zoarium. This section .«hows the 

 manner in which the normal characters of tlie mature region are 

 gradually acquired. The beginning of a cingulum is shown at c, 

 X 287. (177-18.) 



