PROCEEDING OP DOTTED STATES NATIOIJAL MUSEUM. [1886. 



EXPLANATION OF PLATE XXUL 



Pomato8tegii8'8teUatu8 Schmarda. 



Fig. 36. Thoracic uncinus, enlarged 650 diameters. 

 Fig. 37. Abdominal uucinus, enlarged 650 diameters. 



Spirohranchus giganteus (Pall.) Morch. 



Fig. 38. True outline of disk of operculum, small specimen, enlarged 5 diameters. 

 Fig. 39. True outline of disk of operculum, large specimen, enlarged 5 diameters. 

 Fig. 40. Mouth of tube, enlarged 3 diameters. 

 Fig. 41. Operculum, front view, enlarged. 

 Fig. 42. Operculum, side view, enlarged. 



Spirobranchus incrassatua (Kroyer) Morch. 



Fig. 48. True outline of operculum, enlarged 5 diameters. 



