EXPLANATION OF PLATE IV. 



EUNICEA MURICATA.i GROSS ANATOMY. 



Fig. I. Tip of branch shozving arrangement of calicles^ enlarged. 



Fig. 2. Gross cross-section of living branch., enlarged: a, axis cylinder; b, 

 investing mass of small purple spicules; c, main water- vascular 

 canals; d, mesoderm containing small spicules; e, e, e, large spicules 

 supporting calicles; f, f, exterior layer of sinall interlocking spicules; 

 g, g, g, g, retracted tentacles of polyps; h, h, h, mesenteries; i, i, con- 

 voluted gullet wall; j, j, mesenterial filaments; k, k, k, ova; I, 1, "lid" 

 of calicle. 



Fig. 3. Top oj calicle vjith " lid " closed. 



Fig. 4. Top of calicle -with '■'■lid''^ open. 



Fig. 5. A calicle -with side removed to sho'ju contents: a, retracted tentacle; b, 

 convoluted gullet wall; c, c, retractor muscles; d, mesenterial fila- 

 ment; e, lining of calicle; f, f, large supporting spicules; g, small 

 interlocking spicules; h, epidermis extending over polyp; i, i, i, ova. 



Fig. 6. Gross longitudinal section of fresh branch. Lettering as in fig. 1. 



I This species was identified after the Plates were sent to the engraver. 



