78 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



Spicules plates or buttons, knobbed or smooth, often reduced. Feet with 

 a vestige of an end plate or none at all ; walls supported by rods, often 

 3 armed, or plates. Introvert and tentacles with perforated plates and 

 rods. The spicules show tendency to become reduced in many forms. 



Type species. — Cucumaria frondosa (Gunnerus). 



Remarks. — The diagnosis embraces only the members of the genus 

 Cucumaria sensu strictiore. The well-known type species is the only rep- 

 resentative of the genus in the northern Atlantic, while the northern 

 Pacific, including Bering Sea, harbors 3 large species : C. japonicn Semper, 

 C. fallax Ludwig, and C. miniata Brandt. From the west coast of North 

 America a number of smaller forms have been described : C. vegae Theel, 

 C. lubrica H. L. Clark, C. curata Cowles, C. pseudocurata Deichmann. 

 From the Panamic and Peruvian-Chilean region 4 species are reported 

 with certainty, while a fifth species, from Chile, imperfectly described, is 

 briefly discussed below. 



Key to the Species of Cucumaria s. str. Known from the Panamic 



Region 



1. Spicules small, crackerlike buttons or plates with marginal 

 holes or incisions. ... 4. Cucumaria crax, new species 



1. Spicules larger plates and buttons, knobbed to smooth, often 

 reduced in older individuals 2 



2. Feet not restricted to the ambulacra, fairly numerous in the 

 dorsal interambulacra. . . 3. Cucumaria duhiosa Semper 



2. Feet restricted to the ambulacra 3 



3. Tentacles soft, bushy, of equal size. Spicules usually almost 

 lacking in larger individuals (6-10 cm. long), in young indi- 

 viduals as knobbed oblong plates, often with a dentate handle ; 

 supporting rods in feet predominantly 3-armed rods. . . . 

 1. Cucumaria calif ornica Semper 



3. Tentacles rigid with spicules, not bushy, ventral ones small. 

 Spicules strongly knobbed circular plates or smooth ones, usu- 

 ally without a spinous handle. Feet with narrow, bandlike sup- 

 porting rods 2. Cucumaria chilensis Ludwig 



Remarks. — Not included in the key is Cucumaria godeffroyi Semper, 

 which possibly is a strictly southern form. See p. 83. 



