130 Bulletin, Vanderhilt Marine Museum, Vol. Ill 



median line from the rostral tooth to the posterior margin. The 

 gastro-frontal groove is well defined and directed towards the rostral 

 tooth. The cervical and postcervical grooves are also well defined and 

 approach near to each other in the dorsal region. The cardio-branchial 

 ridge is short, neither reaching the postcervical groove anteriorly nor 

 the posterior margin of the carapace posteriorly. 



The abdomen has the first three segments moderately robust, the 

 fourth and fifth segments more compressed, diminishing posteriorly; 

 the sixth segment is twice as long as the fifth and is decidedly carin- 

 ated in the median dorsal line; the carina is rather stout and does 

 not quite attain the posterior margin of the segment. The telson is 

 not quite as long as the sixth abdominal segment and has the dorsal 

 region sulcate; the inferior lateral margins bear three notches and 

 the rudiments of a fourth notch on each side; the tip is armed with 

 a pair of movable spines and several cilia. The peduncle of the 

 rhipidura is well developed; the inner blade is one and two-fifths 

 times as long as the telson, and has the lateral margins very con- 

 vergent distally, the tip narrow, rounded ; a deep sulcus occurs on the 

 proximal inner half of this blade and a very prominent longitudinal 

 ridge approximately in the median line; the outer blade is one-fifth 

 longer than the inner and substantially wider ; the outer lateral mar- 

 gin of the outer blade is relatively straight for a distance equal to the 

 length of the inner blade and terminates in a very rudimentary 

 spinule ; beyond this spine the lateral margins converge to a rounded 

 apex; this distal portion and the inner lateral margin are finely 

 crenulate and ciliated, as are also the margins of the inner blade. A 

 longitudinal ridge transverses the outer blade, extending diagonally 

 from the median proximal region toward the spinule of the outer 

 lateral margin. 



The eyestalk is well developed, slightly flattened dorsally, with a 

 very prominent conical tubercle directed upward. The cornea is sub- 

 spherical with brownish pigment in the preserved specimen. 



The antennulae have the basal article dorsally excavate for the 

 reception of the. eye ; the spine on the outer lateral margin of this 

 joint is well developed and almost reaches as far forward as the distal 

 margin of the cornea ; there is a thin plate-like process from the distal 

 end of the basal article projecting above the eyeball, and fringed with 

 cilia, fan-like. The second antennular article is approximately two- 

 fifths the length of the first and is cylindrical with the dorsal distal 

 end excavate for the reception of the knob-like proximal dorsal end 



