PLATE VII. 



Fui. 12. — Anlis)i;ulix, vii'vvcil frmii the niitor side. Nearly twicf natural .size. 



(i, slime jrlaiiil ii|)iiii tlie slieath of the antispadix. 



F, projectiiii;' Hap of tlu> sheath, partly covering the fonrtli tentacle. 



4, fourth tentaele. 

 l'"iu. 13. — ."^padix, viewed Iruui tlie iiuier side. The louse integument covering its base lias been cut away. 

 Natural size. 



1, first cirrus. 



2, second cirrus. 



3, tliird cirrus. 



Fk;. 14. — Spadix, viewed froju the outer side. Natural size. 

 ( i, slime gland of tlie sheath. 

 SII, line along which the integument has been cut away to expo.se the base <.if the spadix. 



1 , fir.st cirrus. 



2, second cirrus. 



3, third cirrus. 



4, fourtli cirrus, nearly covered by tlie jirojecting Hap of the sjxidix sheath. 

 Fui. 1.5. — First cirrus of the spadix. Nearly natural size. 



Fig. 16. — Second cirrus of the .spadix, viewed from the ventral side. Natural size. 



Kiii. 17. — Third cirrus of the spadix, viewed from tlie dorsal side. Natural size. 



Fig. 18. — Third cirrus of the spadix, viewed from the ventral side. Natural size. 



Fig. 19. — Fourth cirrus of the spadix. Natural size. 



Fig. 20. — Lamellated organ U]ion the median portion of the inferior laliial lobe of the female, viewed from the dorsal 



side. Twice natural size. 

 Fig. 21. — Rliinopliore, viewed from tlie anterior side. X 3. 



DP, aperture of the dorsal pit. 



F, aperture of the fossa. 

 Fig. 22. — Longitudinal section of the rhinophore [lassing through the fo.-su and the tentacle. 



a, nerve. 



b, c, portions of the fo.ssa. c is near tlie opening of the fossa to the exterior. Tlie .section does not extend to 



the clo.sed central end of the fossa. The heavy outer line indicates the extent of the external epithelium. 

 Only as much of the rhinophore as is bounded by ttiis line extends beyond the surface of the body. 

 Fig. 23. — Cross section through the middle of a gill. X 2. 



1, branchial vein. 



2, branchial artery. 



3, stem of gill. 



4, respiratory membrane of leaflet. 



5, supporting portion of leaflet. 



Fk;. 24. — Lamellated region upon the inner surface of the cophali<- sheath of the female, just l)ack of the ventral 

 notch, wliich forms an organ for receiving the spermatopiiore. Below the lamellated region tlie tip of the 

 funnel is .seen; at the sides, some of the most ventral digital tentacles. Twice natural size. 



Fig. 2.5. — Spermatoiihore In situ upon the lamellated receiving region. Natural size. 



Fu;. 2(i. — Rase of the inferior labial lolie of the female, seen from the dorsal side. X 2. 



1, 1', levator muscles. 



2, 2', approxhnator iiiu.scles. 



3, 4, 3', 4', lateral retractor muscles. 

 5, dorsal median retractor muscle. 



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