84 



A crest on the epistome is nearly obsolete in some female 

 specimens. 



The mouth parts are unmodified, and the marsupial 

 plates are not overlapping in mature females, as observed by 

 Dr. Hansen. 



I have always found specimens bearing any indi- 

 cation of a median process on the seventh thoracic segment, 

 as also rudimentary narrowing of the posterior extremity of 

 the abdomen, to be immature males. 



Gulf St. Vincent. One of our commonest marine isopods 

 littoral species. 



Zuzara (isocladus) excavata, n. sp. PI. xxiv., figs. 4 to 6. 



This closely-allied species has the body almost completely 

 glabrous. 



The segments of the thorax differ little in length, except 

 the seventh : seventh segment with a process reaching as far 

 as the end of the abdomen, abruptly contracted to a small 

 obtuse point at the distal end. 



The anterior portion of the abdomen is short, the pos- 

 terior portion triangular in shape, and towards the end again 

 slightly contracted, ending in an obtusely - rounded point ; 

 the inferior surface of this is slightly excavated, as in the 

 preceding species. 



The anterior part of the epistome is not crested, but the 

 surface gradually curves over to the rostrum ; the lateral 

 limbs thin away and recede more than in Z. venosa. 



The antennular flagellum has 12 joints, the basal joint 

 with uneven surface. The antennal flagellum has 15 joints. 



The mandibles have the incisory plates entire, the second- 

 ary plate absent from the left mandible. 



The uropods are broad and lamellate, with the venation 

 more evident than in Z. venosa. 



The female of this species has not been recognized. 



Gulf St. Vincent, littoral. One specimen. 



Zuzara v Exosphaeroma) laevis, n. sp PL xxiv., figs. 7 and 8. 



Body smooth and glabrous. 



Eyes large and prominent. 



Thorax not expanding so much posteriorly as in the two 

 preceding specimens. 



First segment of the thorax shorter than the head, and 

 only slightly longer than those which follow. The seventh 

 segment is without process. 



The anterior abdominal segment is short and acutely 

 angular at the sides. The posterior segment is triangular, 



