NO. 2 DEICHMANN: HOLOTHURIOIDEA; PARTII, ASPIDOCHIROTA 281 



Depth : From shore to about 20 fathoms. 



Specimens examined: Several in various collections in the United 

 States and Europe. A total of 35 collected by the Hancock expeditions 

 from 29 stations. 



Remarks: The Velero III material has confirmed the correctness 

 of the differences previously listed for the two members of the genus. 

 More important than actual measurements are the proportions of the 

 tables — narrovi^er in the Atlantic species, almost square in side view in 

 the Pacific form. 



The Velero material, as w^ell as that v^^hich Dr. Mortensen brought 

 back from Panama in 1916-1917, ranges in length from a few to about 

 20 cm ; the animals shrink considerably when preserved and for practical 

 reasons one avoids picking up the largest individuals, which are more 

 difficult to preserve before they have time to dissolve into slime. In the 

 young individuals, which are paler in color and have fewer appendages, 

 one finds often larger, more delicate tables, with a tall fragile spire and 

 four central holes surrounded by 4 to 10 smaller ones, similar to those 

 found in Parastichopus and Stichopus of similar age. 



Steinbeck & Ricketts note that the species is extremely common in 

 favorable sheltered localities and say that they could easily have col- 

 lected fifty individuals in a short time in the lagoon at Puerto Escon- 

 dido, in the Gulf of California. 



II. Holothuriidae 



Diagnosis: Aspidochirote holothurians with respiratory trees, rete 

 mirabile, well developed tentacle ampillae, and the gonads in a single 

 tuft to the left of the dorsal mesentery. Tentacles 20 to 30, in most 

 species 20; mouth terminal or ventral in position. Shape of body vary- 

 ing from cylindrical to flattened, with appendages in different arrange- 

 ment and different development, as cylindrical tube feet or more 

 papilliform, with sucking disk reduced or lacking. Spicules diversified, 

 in most forms an outer layer of tables, absent or reduced in some groups ; 

 in addition often an inner layer of buttons — regular or irregular, 

 knobbed or smooth — ^rosettes, rods or plates. With the outer layer of 

 tables lacking or reduced, the inner layer usually well developed (ex- 

 cept in some of the surf-loving forms with very few spicules). Tube 

 feet mostly with end plate and a varying number of supporting rods or 

 plates; in the papillae, end plate reduced or lacking and rods, if present, 

 mostly curved and short. 



