Dksimui'tion ok thk FifiniKs i\ Pr.ATK IV. 



FifT. 1 is rediu't'd from a lirawiiig made from the specimen in tlio (ihisgow 

 Museum, referred to in tlie text as the only specimen at present known to he 

 perfect at the top. The dotted outline of the stalk has been copied from a figure 

 by Dalyell. Figs. 3 and i are drawn direct with the camera from one of the Oban 

 specimens. Figs. 5, C, and 7 are constructed from separate camera drawings of 

 the several parts shown, the preparations in all cases being from one of the 

 Oban specimens. 



AliJhabetical List of References. 



Mesentery. 



Egg of EntomoRtracon, embedded 



in mesenterial filament. 

 Retractor muscle. 

 Short mesenterial filament. 

 Long mesenterial filament. 

 Ovum. 



Main canals of rachis. 

 Small canals of rachis. 

 Radial canals. 

 Ectoderm. 

 Mesoderm. 

 Endoderm. 



Fig. 1.— View of an entire specimen of Vinjitlariti : the rachis drawn from the 

 specimen in the Glasgow Museum, and the stalk copied from a figure by Dalyell. 

 The figui-es along the left-lmud side of the rachis indicate the pitch of the leaves 

 at the points opposite which they are placed. Thus the top figure (4S) 

 indicates that at this point the leaves occur at the rate of 48 per inch, x J- 



Fig. 2.— The stem of the specimen in Fig. 1, drawn partly from actual 

 measurements, and the lower part added from figures by Dalyell, and Koren 

 and Danielssen. x h- 



Fig. 3. — Dorsal view of a small portion of the rachis of one of the Oban 

 specimens, showing one pair of leaves and jiart of a second pair, with the rachis 

 connecting them. Shows clearly the characteristic bending upwards of the 

 ventral angles of the leaves. X 0. 



Fig. 4. — Ventral view of the same specimen as in Fig. ;). Shows the bare 

 ventral surface of the rachis ; the mode of attachment of the leaves to the 

 rachis ; and the fusion of the polypes to form the leaves. X 0. 



Fig. 5. — A transverse section of the rachis about its middle, with the whole of 

 one leaf and the base of its fellow of the opposite side. Shows structure of 

 rachis, with the stem, main canals, radial canals, and zooids : also the structure 

 of the individual polypes, and their relations to one another and to the rachis. 

 The most dorsal polype is represented entire ; the others as if bisected 

 horizontally. The several polypes are drawn in different degrees of expansion 

 or retraction to .show the alterations produced thereby in the arrangement of 

 the parts, and especially in the calyx. X 14. 



Fig. C. — Transverse section through the lower end of the rachis, showing the 

 stem, main canals, radial canals, rudimentary polypes ; and the ova, both 

 mature and developing. X 18. 



Fig. 7. — A series of three transverse sections through different parts of 

 polypes. The uppermost section passes through the base of the retracted 

 tentacles, and through the oesophageal portion of the stomach. The middle 

 section passes through the mesenterial filaments just below the stomach, and 

 shows the arrangement of the filaments in a set of two long ones and a set of six 

 short ones. The lower section passes through the body-cavity below the short 

 mesenterial filaments ; it shows the two long filaments and the six ridge-like 

 mesenteries which bear higher nip the short filaments. X 24. 



