176 THE APODOTJS HOLOTHURIANS 



ing to accept Sluiter's genus Microdactyla at its face value, and we are safe in 

 considering that remarkable holothurian as a strongly contracted chilensis. 

 Perrier's descriptions and figures ( : 05) throw a great deal of light on the pro- 

 portions and anatomy of this interesting species. Although M. Perrier had 

 only seven specimens at hand, he regards them as representing five distinct 

 forms, one being the type specimen of ransonnetii, one the type of rugosa, one 

 the type of pigmentosa, two type and topotype of pulchella, and two type and 

 topotype of coriacea brevicauda. Unfortunately, however, he fails to make 

 clear any characters, upon which reliance can be placed, for separating these 

 so-called species; for size, color, proportions, and texture and surface of the 

 body-wall are all characters which vary greatly with the individual and with 

 the method of killing and preserving. Moreover, too close similarity in de- 

 posits must not be expected in such a variable group as the Molpadiidae, and 

 while we may for the present recognize pigmentosa (q. v.), all of M. Perrier's 

 other names appear to fall into the above given list of synonyms. Any other 

 course would necessitate a, new name for every specimen which showed any in- 

 dividual variation a factor in the case for which M. Perrier apparently fails 

 to allow. Miiller ( '50) describes and figures ( '54) some remarkable organs in 

 his type of chilensis which he calls Cuvier's organs, but that they are homol- 

 ogous with the Cuvier's organs of the Holothuriidae is exceedingly doubtful. 

 (See antea, p. 150.) It is very interesting to note that Perrier's specimen of 

 pigmentosa shows the same curious structures. It is somewhat exasperating 

 that the name chilensis must be retained for a species which is most common 

 apparently in New Zealand and occurs in the East Indies and Japan. 



CAUDINA OBESACAUDA. 



PLATE XI, PIGS. 1-5. 



Caudina obesacauda Clark (antea, p. 38). 



LENGTH. 115 mm., of which the tail may be estimated at about one-third. 



COLOR. Pale brown. 



DISTRIBUTION. Eeported only from Marco, Florida, and Galveston, Texas. 

 (See antea, p. 38.) 



REMARKS. This species is very near the preceding, and were it from New 

 Zealand or Australia instead of Florida, it would be difficult to show any real 

 difference between it and chilensis, for it is very doubtful whether the differ- 

 ence in the form of the body is of any significance. Until we have further light 

 on the shape of the body in chilensis, obesacauda may retain a dubious inde- 

 pendence. 



