496 PROCEEDESTGS OF THE NATIONAL MUSEUM vol.99 



interbasal muscle indicates position of the extra nephridinm. The neuro- 

 intestinal vessel, B', emerges from between the two ventral mesenteries to 

 encircle the interbasal muscle. (Lettering as for plates 28 and 29.) 



2. A proboscis, ventral side, X 2. 



3. Tip of proboscis, X 5. 



4. Portion of proboscis near base, X 5. 



5. Ventral side of anterior end of type, X 4. 



Plate 31 

 Arhynchite pugettensis, new species 



1. Map of alimentary canal, X 2, in approximate natural position when animal is 



opened along middorsal line. The foregut is unshaded ; presiphonal gut in 

 solid black ; siphonal gut unshaded ; postsiphonal gut stippled. Muscular 

 mesenteries and details of anterior complex omitted. Only left nephridium 

 shown in entirety. (AV, anal vesicles; OF, nephrostome; CI, cloaca; /, 

 presiphonal intestine; JV, nephridium; Si^ and Si\ beginning and end of 

 siphon. ) 



2. The segment of presiphonal gut between ++ of fig. 1 to show arrangement of 



muscular mesenteries attached near nerve cord. {NC, nerve cord.) 



Plate 32 



Arhynchite pugettensis, new species 



1. Anterior complex, x 5. The foregut has been drawn far to right and only the 



beginning of presiphonal gut is shown. {M, muscular mesenteries of foregut ; 

 M', mesentery of presiphonal gut ; CG, ciliated groove of presiphonal gut ; 

 other letters as for plates 28 and 29.) 



2. Proximal end of detached, incomplete proboscis, X 2: «, Dorsal, and 6, ventral 



aspects ; c, the basal aperture enlarged. 



Plate 33 

 Prometor tenthophila Fisher 



1. Ventral view of paratype, natural size. The thin-walled posterior portion 



of body was badly torn so that reconstruction was necessary. The inflation 

 is probably artificial. Proboscis was evidently undergoing regeneration, 

 la. Ventrolateral aspect of anterior end of paratype, X 2. 



2. Ventral view of anterior end of type, natural size, to show the basal funnel 



of proboscis (leading to mouth), the two setae, and single nephridiopore. 



2a. Lateral view of proboscis funnel, enlarged. 



2b. Setae (S), nephridiopore {NP), and surrounding skin of type, X 10. The 

 tip of each seta is missing. 



2c. Basal portion of nephridia, showing the compressed fan-shaped nephrostomes 

 or ciliated funnels {CF) , X 5. A portion of nerve cord {NC) has been re- 

 moved ; N, thinner-walled portion of nephridium. 



Plate 34 

 Prometor benthophila Fisher 



1. Anterior portion of alimentary canal of paratype arranged to show the dif- 

 ferent parts of the foregut and circulatory system, x 4 In the natural 



