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 
35 were enlarged fifty-five diameters. With the same exceptions, 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. 8. Hydranth of P. symmetrica, showing 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 Eudendrium distichum : a, large trumpet-shaped 
hypostome, a family characteristic ; ò, ultimate ramulus with its nar- 
rowed, annulated base; c, portion of a branch. 
Fig. 5. Tho 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. distichum : a, main stem ; 5, branches. 
PLATE II. 
Fig. 7. Portion of a branch of Cryptolaria longitheca Aim. The specimen is 
peculiar in the very large number of additions which have been made 
to the hydrothecx, thereby making somo 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. Isa more typical form of the same, from the same locality. 
Fig. 9. Two somewhat abnormal hydrothece 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 Cryptolaria 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 : 5, sections of the stem of C. 0 
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 Oryptolaria conferta Allman : a, the distal 
end of the cauline tube. 
Fig. 15. An unusually large form of the same. 
