﻿Plate 36 



1, 2, Phascolosoina punlarenae Grube, Panama. Dorsal papillae from postanal 

 region, 0.105 by 0.14 mm.; X 200. 



3, Phascolosoma agnssizii, Kefcrstein; Monterey Bay, Calif. A dorsal papilla 



from postanal region, 0.2 by 0.24 mm., to show typical arrangement of 

 platelets; X 200. 



4, Phascolosoma agassizii; X 16. Dorsal view of head. The crown of 24 



tentacles has been bent rather unnaturally dorsalward; nuchal organ in 

 middle. 



5, Phascolosoma agassizii; X 2. Large specimen from Humboldt Bay, Calif., to 



show origin of ventral retractors; nerve cord omitted from mid ventral 

 line + +. 



6, Phascolosoma agassizii; X 2. Dissection of a specimen from Bodega Head, 



Calif., near the type locality. A short section of esophagus has been 

 removed to show attachments of fixing muscle F (F', esophageal branch) ; 

 A'', nephridium. 



Plate 37 



Hooks of specimens from Panama to Humboldt Bay, Calif., for comparison. 

 Measurements in millimeters; the first number is total height; the second is 

 extreme width of base. Enlarged X 400. 



I, 2, Phascolosoma punlarenae Grube, Panama; 0.059 X 0.07 and 0.05 X 0.05; 



a, the thickening of base similar to that of Ph. nigrescens (pi. 39, fig. 2). 



3, Phascolosoma punlarenae, from Espfritu Santo Island, Baja Calif.; 0.0875 X 



0.077. 

 4-15, Phascolosoma agassizii Keferstein: 



4, San Quintin, Baja Calif.; 0.063 X 0.059. 



5, Santa Rosa Island, Calif.; 0.07 X 0.07. 



6, 7, Point Pinos, Monterey Bay, tide pool in granite rocks; 0.08 X 0.08 and 



0.087 X 0.066. 



8, Montere}' Bay, from colony of AUopora, 50 feet depth; 0.06 X 0.06. 



9, 10, Monterey Bay, common tide pool form from under granitic stones on 



fine sand or mud. From same specimen, 0.063 X 0.063 and 0.063 

 X 0.056. 



II, Monterey Bay, at Hopkins Marine Station, form with dark purple brown 



introvert markings; 0.059 X 0.063. 



12, Bodega Head; 0.059 X 0.059. 



13, 14, Mendocino, from one of Keferstein's paratypes; 0.06 X 0.06 and 0.056 



X 0.05. 

 15, Humboldt Bay, from a light colored specimen; 0.07 X 0.066. 



449 



