150 HOLOTHURIIDAE. 



are fairly distinct. As a rule the distinction between the dorsal and ventral 

 surfaces is very marked but this is not always the case. The specimens were 

 taken at Taboquilla and Perico Islands, Panama, in October, 1904. 



Holothuria marenzelleri. 

 Ludwig, 1883. Ber. d. oberh. Ges. f. Naturk., 22, p. 167. 



A single specimen was taken at Chatham Island, in the Galapagos, in Janu- 

 ary 1905. It measures 100 mm. in length by 35-40 mm. in diameter. The 

 species has been recorded previously from the Galapagos Islands, although 

 it was originally described from the East Indies. 



Holothuria monocaria. 



Lesson, 1830. Cent. Zool., p. 225. 



The specimens which I refer (though not without hesitation) to this com- 

 mon species are quite young, one about 40 mm., the other only 11 mm. long. 

 The larger is nearly white and is possibly from Tahiti but nothing is certain 

 as to the locality beyond the fact that the specimen was collected by the 1899- 

 1900 expedition. There are very few buttons in the skin and the tables show 

 considerable diversity of form. The smaller specimen is also nearly white. 

 It was taken October 12, 1899, at Fakarava, Paumotu Islands. The tables 

 are well formed but diversified with eight to thirteen marginal holes in the disk. 

 There are apparently no buttons in the skin. If these specimens really are 

 monocaria it would seem to be probable that tables arise some time before 

 buttons and that the buttons only gradually become so numerous as to form 

 the layer present in adults. But of course, only a series of indubitable growth- 

 stages can determine whether this is the case. 



Holothuria pardalis. 

 Selenka, 1867. Zeits. f. w. Zool., 17, p. 336. 



A single specimen taken October 20, 1899 at Makemo, Paumotu Islands, 

 seems to belong to this species but the condition is poor and the calcareous 

 particles are so corroded that it is impossible to be sure of the identification. 



Holothuria scabra. 

 Jaeger, 1833. De Holothuriis, p. 23. 



A single specimen of moderate size was taken at Guam, Ladrone Islands, 

 February 27, 1900. 



