88 LOWER PENINSULA. 



growth, unite laterally with them and inclose irregular loops. 

 All the tube ends, after the departure of a branch tube, bend into 

 an erect position and usually grow no further. The width of the 

 tubes of different specimens varies from one to two millimeters. 

 The identification of this species with the European form, described 

 by Goldfuss, is made with some hesitation, and is intended rather to 

 express their great resemblance than a full identity. Found in the 

 Hamilton group of Thunder Bay and Little Traverse Bay, incrust- 

 ing other corals. 



Plate XXXIII. — Fig. 2 represents a specimen from Little Trav- 

 erse Bay incrusting a Stromatopora. 



AULOPORA CONFERTA, Winchell. 



Incrusting, reticulated, or continuous laminar expansions formed 

 of laterally anchylosed conical tubules, arranged in fan-like, spread- 

 ing order by emanation from the prolific gemmation of a single 

 mother-tube according to the bilateral, forking mode of growth ex- 

 hibited in the generic description. The club-shaped tubules are 

 about one millimeter wide across the thickest part ; the channels 

 of the erect, circular orifices measure about half of a millimeter. 

 Found abundantly as incrustation of other corals in the blue fos- 

 siliferous shales of Little Traverse Bay. 



Plate XXXIII. — Fig. i represents a solid incrustation of the sur- 

 face of a Stromatopora by this species of Aulopora. 



AULOPORA ERECTA, N. Sp. 



Massive, incrusting expansions formed of very stout-walled tubes, 

 about two or two and a half millimeters in diameter. On the basal 

 side of the expansions, broke loose from the incrusted body, the 

 prostrate, flattened tubes are noticeable, grown into a dense agglo- 

 meration by repeated rapid gemmation. From this basal sheet the 

 tubules bend into a vertical position, and continue to grow in this 

 direction for some length parallel with each other, and producing 

 no more side branches at the rapid rate of the prostrate portions. 



