PLATE IV. 



Fig. 4. — Mantle chamber of female viewed from the ventral side. The mantle has teen turned hack over the 

 posterior end of the body. 



B, raised and overlapping border of the nidamental gland. 



BV, branchial vein of the anterior gill. 



F, base of funnel. 



GA, anterior gill. 



GP, posterior gill. 



LM, lateral portion of mantle. 



N, nidamental gland. 



OV, protruding end of oviduct: oviducal papilla. 



PA, preanal papillae. 



SM, shell muscle. 



VM, ventral portion of mantle. 



Y, thickened portion of mantle between the inturned ends of the nidamental gland. 

 Fi(i. 5. — Cephalic region of female viewed from the dorsal side. The hood has been slit open along the median line 

 to show the arrangement of the labial lobes and tentacles. 



B, buccal mass. 



CR, crescentic ridge upon the posterior face of the hood. 



DM, dorsal portion of the mantle. 



Ho, hood. 



L, lamellated organ upon the center of the inferior labial lobe. The fan-like cirrus-bearing portions of the lobe 



are seen at the sides of the lamellated organ. 

 SIX, superior labial lobe. 

 Fig. K. — Funnel, opened and viewed from the ventral side. 



C, infundibular portions of the cartilage showing through the integument of the dorsal wall of the funnel. 

 CR, crus of funnel. 



L, ligamentous band of the integument extending from the posterior edge of the funnel backward over the 



surface of the shell muscle. 

 M, shell muscle, 

 V, valve of funnel 



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