PLATE IV. 



Figs. 1-4. Molgula gigantea, Cunningham. 

 Figs. 5-8. Molgula gregaria, Lesson. 



Fig. 1. Molgula gigantea, a small specimen, from the left side ; natural size. 



Fig. 2. Part of the branchial sac of Molgula gigantea, from the inside, natural size, t<> 



show the longitudinal folds (br.f.), and the distant transverse vessels (tr.). 

 Fig. 3. Part of the preceding figure, between two folds, greatly enlarged, to show the 



infundibula and the stigmata (Hartn., obj. 4). 

 Fig. 4. Dorsal part of the branchial sac of Molgula gigantea, from the inside, natural size, 



showing the dorsal tubercle, the peripharyngeal bands, part of the tentacular 



circlet, the dorsal lamina, the oesophageal aperture, and part of the branchial 



sac 

 Fig. 5. Molgula gregaria, a large specimen, from the dorsal edge of the right side : 



natural size. 

 Fig. 6. Part of the branchial sac of Molgula gregaria, from the inside ; magnified (Hartn., 



obj. 4). 

 Fig. 7. Dissection of the viscera on the right side of the mantle in Molgula gregaria, from 



the inside, showing the genital gland (g.), and the renal organ (''■".); 



natural size. 

 Fig. 8. Part of a section through the test of Molgula gregaria, showing the large stellate 



protoplasts (t.e. ), in some of which clear vacuoles have appeared : magnified 



(Haitn.. obj. 7). 



