OY TJIE LEYDEN MUSEUM. 195 



The varieties described by Boas (p. 133, PI. 6, fig. 95), 

 urceolaris and iypica^ can scarcely be maintained, as the 

 transitions between them are most gradual, and neither 

 seems to inhabit special regions. 



One of the specimens from the W. Pacific had the hinder 

 part of the shell yet attached. It is long and slender, 

 conic, terminating into a point, quite as Boas described it 

 (p. 132, PI. 3, fig. 39, PI. 4, fig. 56). Contrary to this 

 author, I could nothing observe about a constriction near 

 the end, which separates an embryonic shell from the rest. 

 At this place I observed a very minute septum, which, if 

 I am not mistaken, also appears in the figure of Boas 

 (PI. 3, fig. 39), without being mentioned in the text. A 

 .similar, but much larger, transverse septum occurs, as is 

 well known, somewhat behind the middle of the complete 

 shell. The whole surface is very minutely striated, especially 

 in transverse direction. 



Genus 6. Diacria Gray. 

 Species 1. Diacria trispinosa (Lesueur). 



Animals: 



N. Atlantic Ocean, (5^ N., 24^ W.), 1S79, 1 sp., R. J. Lusink. 



,/ (4^N., 24" VV.), 1880, 1 sp., » 



Empty shells: 



N. Atlantic Ocean, (24" N., 22" W.), 1880, 1 sp., R. J. Lusink. 

 Mediterranean (Sicily), date?, 1 sp., Cantraine. 



Species 2. Diacria quadridentata (Lesueur). 



Animals: 



Indian Ocean, April '06, 1 sp., Buitendijk. 



// (Gulf of Bengal), August 'OG. 1 sp., // 



Empty shell: 

 Red Sea, 1861, 1 sp., Keferstein. 



Notes from the Leyden Museum, Vol. XXIX. 



