MUSEUM OF COMPARATIVE ZOOLOGY. 251 



EXPLANATION^ OF THE PLATES. 



All the figures were drawn with the aid of the camera-lucida, and with the exception of Figs. 1 and 

 85 were enlarged fifty-five diameters. With the same e.xceptions, all are represented as enlarged thirty 

 diameters. 



PLATE I. 



Fig. 2. A portion of the trophosome of Pennaria symmetrica : a, main stem ; 

 b, branch ; c, ultimate ramulus or pedicel. 



Fig. 3. Hydranth of P. symmetrica, sho^ving the capitate and filiform tentacles 

 and the large body of the hydranth. This specimen had been some- 

 what flattened by pressure, so that one or two more of the filiform 

 tentacles appear than are usually seen in such a view. 



Fig. 4. Portion of trophosome of Eudcndrium distichum : a, large trumpet-shaped 

 hypostome, a family characteristic ; h, ultimate ramulus with its nar- 

 rowed, annulated base ; c, portion of a branch. 



Fig. 5. The same ; letters as in Fig. 4 : d, the mouth at the extremity of the 

 large hypostome. 



Fig. 6. A portion of the main stem of E. disticlium : a, main stem ; b, branches. 



PLATE IL 



Fig. 7. Portion of a branch of Cry2)tolaria longitheca Allm. The specimen is 

 peculiar in the very large number of additions which have been made 

 to the hydrothecffl, thereby making some of them twice their original 

 length. In the original condition the free portion is about equal, or a 

 little greater in length than the part imbedded in the stem. 



Fig. 8. Is a more typical form of the same, from the same locality. 



Fig. 9. Two somewhat abnormal hydrothccaj from the extremity of a branch of 

 the same specimen as Fig. 8. 



Fig. 10. The same, from Professor Allman's type-specimen. 



Fig. 11. A colony of the peculiar gonangia-like organisms found attached to the 

 stems of Cnj})tolaria longitheca Allman. 



Fig. 12. A longitudinal section through the stem and portion of the colony of Fig. 

 11 : a, apertures through which the vessels communicate by a network 

 of stolons at their bases. 



Fig. 13. A transverse section of the same : h, sections of the stem of C. IcmgUhfcn 

 upon which they were growing : a, sections of the root-like stolons of 

 the gonangia-like colony. 



PLATE III. 



Fig. 14. The distal end of a branch of Cryptolaria conferta Allman : a, the distal 



end of the caulinc tube. 

 Fig. 15. An unusually large form of the same. 



