PLATE VII. 
Figs. 1, 2. Thenea schmidtii, 
Figure 1. View of a specimen ; nat. size. 
,, 2. Section through a part of the choanosome, showing the flagellated 
chambers and the arrangement of the microscleres ; the tangential 
position of the actines of the calthrops is best seen in the canal in the 
lower right-hand corner; x 73. 
Fig. 3. Thenea muricata, .... 
„ 3. A transverse section through the ectosome and adjacent choanosome, 
showing the small eurypylous chambers and abundant mesoderm ; 
X 73. 
Fig. 4. Thenea intermedia, 
4. A transverse section through the ectosome and adjacent choanosome ; 
X 73. 
Fig. 5. Pilochrota lendenfeldi, 
„ 5. View of a specimen ; nat. size. 
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