116 Bulletin Vanderbilt M. trine Museum, Vol. VI 



Distribution : Blanche Bay, New Britain, 50 to 100 fathoms ; 

 D'Entrecastreaux Group, New Guinea (Borradaile) ; "Siboga," 

 Station 306, Lobetobi Strait, 247 m. ; "Siboga," Station 312, Saleh 

 Bay, north coast of Sumbawa, depth 274 m. (de Man) ; Bima, 

 Sumbawa Island (Boone). 



Material examined: One specimen, about 20 millimeters, 

 long, taken at Bima, Sumbawa, Dutch East Indies, October 23, 

 1931, by the "Alva" ; depth not cited. Other specimens from this 

 station all shallow water records. 



Remark : Mr. Borradaile notes that this species forms a part 

 of the food of the pearly nautilus. 



Technical description: The single specimen obtained by 

 the "Alva" appears to be the first record of the species since the 

 type series was captured, and very substantially extends the south- 

 ern distribution of this most primitive genus of the Pontoniinae. 



The Sumbawa specimen has the rostrum about twice as long as 

 the carapace, slender, compressed laterally, recurved, the portion 

 just beyond the orbit dipping concavely, the distal half thrust de- 

 cidedly upcurved, both dorsal and ventral margins dentate, the 

 formula being f^, the distribution on the dorsal margin be- 

 ginning on the epigastric region, where there are four spines, suc- 

 ceeded by two, the largest of the series, on a crest above the orbit, 

 followed by four small teeth in series above the antennulae next 

 to a non-dentate area, and there are three small separated teeth 

 near the tip, the thirteenth tooth being subdistal. The twelve 

 ventral teeth are nearly subequally spaced, the most proximal one 

 being just in advance of the cornea, the terminal one, at the apex. 

 The carapace is smooth, rather compressed, slender, the antennal 

 spine present, slender ; the hepatic spine small, acute, nearly bran- 

 chiostegal in position. The abdominal segments are rather com- 

 pressed, the first to third, with the lateral margins deep, convex; 

 the third segment is produced to a median dorsal point posteriorly ; 

 the fourth to sixth segments decrease in breadth ; the sixth seg- 

 ment is elongated, one and one-half times the length of the fifth 

 segment or three-fourths as long as the telson. The telson is 

 slightly shorter than the uropoda and is quite narrowed and tap- 

 ered, the dorsal surface channelled in the median line and mar- 

 gined on either side dorsolaterally by a longitudinal ridge. These 

 ridges bear three pairs of articulated spines, the proximal pair 

 being placed little more than one-third of the telsonic length from 



