324 ASAJIRO OKA AND ARTHUR WILLEY. 
EXPLANATION OF PLATES XVII and XVIII, 
Illustrating Mr. Asajiro Oka’s and Mr. Arthur Willey’s paper 
“On a New Genus of Synascidians from Japan.” 
PLATE XVII. 
Sarcodidemnoides misakiense, nov. gen. et spec. 
View of colony, natural size and colour. Length 12 em., height 6 cm. 
width about 3 c.m. 
PLATE XVIII. 
Fie, 1.—Diagrammatic view of the canal system of S. misakiense, 
showing peripheral and central portions of the system. 
Fic. 2.—Transverse section through a whole colony to show the lateral 
compression and the narrow base. Dark points round margin are Ascidio- 
zooids ; the round bodies lying deeper in test are embryos and larve. 
Fic. 3.—Horizontal section through the branchial sac of an Ascidiozooid to 
show the position of the openings. The atrial opening is placed far back, 
a characteristic feature for the Didemnide. The surface-layer of bladder-cells 
in the test is shown on the right-hand side of the figure. Zeiss, DD, 2. el. 
Cloaca, opening by cloacal aperture into peripheral canal. 
Fic. 4.—Section showing an egg-cell in the body-cavity surrounded by 
blood-corpuscles. 
Fic. 5.—Section through the branchial funnel of an Ascidiozooid to show 
the collar-like aggregation of calcareous spicules. Zeiss, H, 2, cam. luc. 
Fic. 6.—Isolated spicules from the test. Zeiss, E, 4, cam. luc. 
Fic. 7.—Tadpole of 8. misakiense to show the ring of tentacle-like pro- 
cesses surrounding the three adhering papille. Zeiss, B, 2, cam. luc. 
