20 PPP. KEPOKT OF PKOOllESS. C. E. BEEOIIER. 



EXPLANATION OF PLATES. 



Plate I. 

 EcHiNOCARis sociALis, Beecher. 

 Page 10. 

 Fig. 1. A small example with the abdomen directed pos- 

 teriorly, in a line with the longer axis of the car- 

 apace. 



" 2. A similar specimen, in which the abdomen is ele- 

 vated above the dorsum. 



*' 3. An individual with the valves opened and the ab- 

 domen closely curving around the posterior mar- 

 gin of the left valve. 



" 4. Similar to the preceding, but with the abdomen 

 protruded in front of the valves. 



" 5. An exailiple j)reserving the carapace and four na- 

 ked segments, showing the form and ornamenta- 

 tion of these parts of the test. 



" 6. A carapace with the valves opened, showing the 

 distinct furrow limiting the cejDhalic and thoracic 

 portions, the optic si^ots indicated by dotted lines, 

 and the nodose ridges and elevations ornamenting 

 the valves. 



" 7. A smaller carapace, presenting immature charac- 

 ters, belonging to a young example. 



" 8. Fragment preserving three abdominal segments, 

 the telson and lateral spines showing the form 

 and ornamentation. 



*' 9. Two segments of another fragment, enlarged to two 

 diameters, to show the ornamentation and nature 

 of the articulating surfaces. 



" 10. A small telson with the attached lateral spines, 

 showing their form and longitudinal carinse. 



" 11, A piece of shale with an impression of the caudal 

 plate, and with one of the lateral spines, belonging 

 to a large individual. 



