different in several more or less important details, I consider it as a variet\- of the last described 

 species. Comparing the capitulum we see that the occludent segment of the scutum of this 

 specimen is more than twice as long as the basal segment, and that it does not grow wider 

 towards the apex but has about the same width throughout its length. The tergimi of this 

 specimen, though deeply furrowed like the same valves in D. Vershtysi, does not show the 

 fourth prominence just above the apex of the carina. The carina itself not only has almost 

 the same o-eneral shape, but its basal portion has exactl)- the particular form which is so 

 characteristic of D. Versluysi. 



Only one specimen represents this form and this specimen, the length of the capitulum 

 in which is about 6 mm., has been dissected to prepare the valves and to make out its identity: 

 so that the "type" of this form no longer e.xists and this alone would be a reason for not 

 introducing it into science as a new species. As, further, its relation to D. Versluysi is very 

 close I think it right to indicate it as D. Versluysi Var. The single specimen was taken at : 



Stat. 258. Dec. 12 — 16, 1899. Tual anchorage, Kei Islands. Depth 22 m. Bottom: Lithotham- 

 nion, .sand and coral. 



Genus Megalasma Hoek 

 HOEK, Cirripedia of the "Challenger", 1883, p. 50. 



This genus was founded (1883) for a very characteristic Cirriped dredged during the 

 cruise of the "Challenger". It belongs to the same natural group of genera as Poecilasvia, 

 Dichelaspis and Lepas and is nearly related to the tirst of these three. 



In 1 894 Weltner ^ described a second species of this genus and gave it the name of 

 M. carino-dentatum . A third was collected by H. M. S. "Siboga" in 1899. 



The diagnosis given for this genus in the "Challenger" Report holds good for the forms 

 discovered later, with one exception.; the triangular form of the scutum which was so very 

 striking in M. striatum is, strictly speaking, gone in M. lineatum (and so far as can be judged 

 from the sketches of Weltner, the same is the case in M. carino-dentatuni), there being a 

 distinct though short basal margin. Hence, I propose to have the diagnosis changed so far that 

 the scuta are not called triangular but approaching more or less to a triangular form. 



For the determination of the species known at present, the following table may be of use ; 



Megalasma 



A. Dorsal margin of the carina developed into a broad flattened part 

 forming the continuation of the downwards inclined portions of the 



tergum along their carinal margin M. striatum. 



B. Dorsal margin of the carina not forming a broad flattened part. 



a. Dorsal margin of the carina having a tooth-like excrescence. . ]\I. cariiio-dentattim. 



b. Dorsal margin of the carina without a tooth-like excrescence. . M. lineatum. 



' Weltnkr, W., Zwei neue Ciiiipcilien aiis dem Indischen Ocean. Sitz. Ber. Ges. Natmf. Fieunde zu Berlin, 1S94, p. 80. 



3° 



