142 CLARKE ON HYDROIDS. 



Explanation of Plates, 

 plate VII. 



1. Calyptospadix cerulea, X25, portion of a branch. 



2. The same, X25, portion of the main stem. 



3. 4. The same, X25, portions of branches. 



5. The same, X25, male sporosacs ; a, spadix. 



6. The same, X25, female sporosacs. 



7. The same, X80, a female sporosac, a, the large spadix. 



8. The same, x80, a female sporosac, side view, a, spadix. 



9. The same, x80, a female sporosac, a, spadix; b, developing ova. 



10. Eudendrium carneum, x25, portions of branches, a, a young hydranth. 



11. The same, X25, a large terminal hydranth. 



12. The same, X80, female sporosacs. 



13. The same, X25, female sporosacs. 



14. The same, X25, an abnormal twin planula or two hydranths developing simultaneously from one 

 planula. 



15. The same, X80, a normal planula. 



16. The same, X25, a normal planula. 



17. The same, X25, a branch with male sporosacs. 



PLATE VIII. 



18. Stylactis arge, X25, an adult hydranth ; a, constriction in stem ; b, b, hydrorhizal growths by which 

 the hydranth will attach itself after becoming free. 



19. The same, x25, a hydranth with female medusoids. 



20. The same, X§, a colony. 



21. Bougainmllea rugosa, X25, a portion of a branch with hydranths and sporosacs. 



22. The same, X25, portion of main stem with hydranths and sporosacs. 



23. The gonocheme of the same, x80. 



24. The same individual gonocheme two days later, x80 ; showing the great increase of the tentacles in 

 leno-th but no addition to their number. The oval, granular mass that has become separated from the manu- 

 brium I do not understand ; it may be abnormal. 



PLATE IX. 



25. LoveneUa gracilis, X25, portion of main stem and hydrorhiza. 



26. The same, x25, a hydranth expanded. 



27. The same, X 25, the hydrorhiza. 



28. The same, X25, the hydrorhiza thirty-two hours later. 



29. The same, x25, terminal portion of stem with lateral bud, the latter to form the next internode of 

 the stem. 



30. The same portion, X25, eight hours later. 



31. The same portion, X25, six hours later. d 



32. The same portion, X25, seven hours later. 



33. The same portion, X25, four hours later. 



34. The same portion, x25, seventeen hours later. 



35. The same, X25, female gonangium with developing blastochemes. 



36. The same, X25, gonangium. 



37. The same, X 25, gonangium. 



38. The same, x25, gonangium and hydrotheca. 



39. The same, X80, blastocheme ; a, lithocysts, b, marginal tentacles, c, sporosacs, d, manubrium. 



40. Hydractinia echinata, a, feeding zooids, b, reproductive zooids, c, tentacular zooids, d, chitinous 

 spines, e, an abnormal form of feeding zooid,^ an abnormal tentacular zooid. 



