166 THE APODOTJS HOLOTHURIANS 



correctness of his position, but add Ludwig's spinosum to the list of synonyms. 

 For my part, I believe that at least three species are confused under the above 

 synonymy ; but as Perrier, and Koehler and Vaney have had far more material of 

 musculus for study than is accessible to me, I defer to their judgment. It seems 

 to me very likely that musculus is a small species, confined to the Mediterranean 

 Sea and eastern Atlantic Ocean, which never outgrows its Ankyroderma stage, 

 while violaceum is a quite different and much larger species. As for spinosum, 

 I believe it, too, will prove to have constant specific characters. Some of the 

 specimens of danielsseni in the National Museum collection are remarkable for 

 the apparent absence of phosphatic deposits, and I think it quite possible that 

 these are really a fourth species. But these questions can only be settled when 

 a large amount of material of all ages from the Mediterranean Sea, Atlantic, 

 South Pacific, tropical Pacific, Indian and south Indian oceans can be brought 

 together and carefully compared. 



MOLPADIA MAHOCCANA. 



PLATE X, PIGS. 17, 18. 



Ankyroderma maroccanum R. Perrier, 1898, p. 1666; 1903, p. 533. Calcareous par- 

 ticles, pi. xxn, figs. 9-15. 



LENGTH. Not given; presumably 20-35 mm. 



COLOR. Not given; presumably grayish, more or less mottled with red- 

 brown or violet. 



DISTRIBUTION. Reported only from off Cape Ghir, Morocco, 2,210 m. (R. 

 Perrier). 



REMARKS. Although four specimens of this form were taken, it is by no 

 means certain that the differences between it and the preceding species are con- 

 stant; but, as Perrier says, in the present state of our knowledge the two are 

 well separated from each other. 



MOLPADIA LOBICATA. 



Ankyroderma loricatum R. Perrier, 1898, p. 1666; 1903, p. 535. Calcareous par- 

 ticles, pi. xxii, figs. 23-28. 



LENGTH. 55 mm., of which the tail is 1 ; diameter, 10-15 mm. 



COLOR. Very deep red-brown; tail grayish. 



DISTRIBUTION. Reported only from off Senegal, 1090-2324 m. (R. Perrier). 



REMARKS. Of this form three specimens were taken by the "Talisman" in 

 1883. It is very close to the preceding species, with which it may be identical, 

 and its separateness from musculus is therefore open to question. The latter 

 was taken by the "Talisman" at a neighboring station off Senegal, but in much 

 shallower water. 



