ORTMANN : TERTIARY INVERTEBRATES. 



EXPLANATION OF PLATE XI. 



PAGE 



Fig. i. CIDARIS ANTARCTICA Ortm. ... 51 



Patagonian beds ; 30 miles north of upper Rio Chalia. 

 i a. Fragment of spine. 

 \b. Cross section of spine. 



ic. View of articular surface of lower end of spine. 

 id. Plate. 

 Fig. 2. HYPECHINUS PATAGONENSIS (d'Orb.). . . . .. . . . 52 



Patagonian beds ; Darwin Station, San Julian. 

 Upper view of the only specimen in the collection. 

 Fig. 3. TOXOPNEUSTES PRECURSOR Ortm. ....... 53 



Patagonian beds ; Oven Point, San Julian. 



30:. Upper view of a large specimen, slightly worn. 

 3^. Side view of another specimen, 2/1. 



Fig. 4. SCUTELLA PATAGONENSIS Des. ........ 55 



Patagonian beds. 



40. "Alate form," adult, upper view ; Salt Lake. 

 46. "Alate form," young, lower view; Salt Lake. 

 4<r. "Rotundate form," medium size, upper view; Oven Point, 



San Julian. 



\d. "Rotundate form," adult, lower view ; Upper Rio Chalia. 

 4<?. "Rotundate form," young, lower view; Oven Point, San 



Julian. . 

 Fig. 5. TEREBELLA MAGNA Ortm. ......... 63 



Patagonian beds; Oven Point, San Julian. 



5. Isolated tube (with remains of another one), side view. 

 5<J. View of terminal opening. 



Fig. 6. CELLARIA FISTULOSA (L.) 64 



Patagonian beds ; Shell Gap, Rio Chico. 



6a. Fragment of a branch, showing achylosis on upper end. 

 6b. A number of zocecia, enlarged. 



All of the figures, unless otherwise stated, are natural size. 



(VOL. iv) 



