160 Bulletin Vanderbilt Marine Museum, Vol. VI 



This genus is placed in the Pontoninae with considerable hesi- 

 tation. Dissection of additional material and females is necessary 

 to clarify the phylogenetic relationship of this remarkable coral 

 crevice shrimp. 



Genotype : Vanderbiltia rosamondae, new, from coral, Venus 

 Point Reef, Tahiti, Society Islands; deposited in the Vanderbilt 

 Marine Museum. 



Vanderbiltia rosamondae, new species 

 Plates 41 and 42 



Type: One male, taken in coral, Venus Point Reef, Tahiti, 

 Society Islands, August 15, 1931. 



Distribution : So far restricted to the type. 



Material examined: Type. 



Technical description: Carapace glabrous, slender, typi- 

 cally Sergestid, 3 millimeters long, with the rostrum consisting 

 of a concave median process extending between the eyes and as 

 far forward as they do, being one-half as wide as one cornea ; ex- 

 tending above the eye with the lateral rostral margin carinate, 

 surrounding the upper side of the eye and distally forming a tri- 

 angulate denticle, immediately above the anterior margin of the 

 eye, beyond which tooth the rostral apex is decidedly deflected, in 

 an abrupt curve, this tip of rostrum being bent downward to 

 midway the orbit. The dorsal surface of rostrum is a deep wide 

 groove. The infraorbital angle is obscure, the frontal margin of 

 carapace being closely applied here to the antennal base. The 

 anterolateral angle is blunt. The abdominal terga are smooth, 

 dorsally rounded, 8 millimeters long; the sixth segment is one 

 and one-half times as long as the fifth segment, but only five- 

 sixths as long as the telson, which is dorsally convex, tapered dis- 

 tally, triangulate, armed with three pairs of articulate spines on 

 the distal half ; the telsonic border bears three pairs of long, spine- 

 like bristles ; the apex of the telson extends as far as the subdistal 

 tooth of the outer lateral margin of the uropod blade. The inner 

 blade is a little longer than the telson, narrowly ovate ; the outer 

 blade is slightly longer and wider than the inner blade, with a 

 subdistal tooth on the outer margin and a transverse suture ex- 

 tending inward obliquely from the tooth and beset with denticles 

 in series; both blades have the margins crenulated and ciliated. 



