296 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 108 



of Munida irrasa A. Milne Edwards from North Carolina and Florida, 

 which had been collected by the U. S. Fish Commission many years 

 ago, also had peltogastrids present that proved to be new. Descrip- 

 tions of this new genus and new species also are given here. 



The two new genera are gregarious in their habit of growth, but 

 they differ markedly from the other gregarious forms in external 

 appearance and in various aspects of their internal anatomy. One of 

 their most distinctive features is the peculiar orientation of the 

 mesentery in relation to the stalk. 



Family Peltogastridae 

 CyphosaccuSy new genus 



Genotype: Cyphosaccus chacei, new species. 



Diagnosis: Gregarious; body elongate, V- or U-shaped; stalk on 

 the left side. Mantle aperture a blind canal which eventually opens 

 to form a birth pore. Testes saccular, small, situated near posterior 

 end. Vasa deferentia directed posteriorly. Colleteric glands in the 

 vicinity of the stalk. On Galatheidae. 



When the animal is viewed with the anterior arm to the left and 

 directed upward, the side facing the observer is the mesenterial or 

 dorsal surface. The curvature of the sac is therefore in a lateral 

 direction, with the stalk originating on the left side. 



Cyphosaccus chacei, new species 



Figure 1; Plate 1, figure 1 



Syntypes: Off Cayo Coco, Cuba, Atlantis Station 3397, lat. 

 22°34'30'' N., long. 78°16' W., 180 fathoms, Apr. 28, 1939; 18 speci- 

 mens on one Munida irrasa A. Milne Edwards. Harvard-Havana 

 Expedition, Atlantis. MCZ 11431. 



Additional specimens: Off Cayo Coco, Cuba, Atlantis Station 

 3399, lat. 22°35' N., long. 78°2' W., 180 fathoms, Apr. 28, 1939; 10 

 specimens on one Munida irrasa A. Milne Edwards. Harvard- 

 Havana Expedition, Atlantis. MCZ 11432. 



Off Havana, Cuba, Albatross Station 2337, lat. 23°10'38" N., long. 

 82°20'21'' W., 199 fathoms, Jan. 19, 1885, 15 specunens on one 

 Munida irrasa A. Milne Edwards. Albatross coll. USNM 100943. 



Off Pelican Island, Barbados, Station 7, 80 fathoms. Mar. 16, 1918; 

 1 specimen on Munida irrasa A. Milne Edwards. Barbados-Antigua 

 Expedition. USNM 57962. 



Diagnosis: Body slender and V-shaped, with the stalk at the 

 vertex of the angle. Length of anterior arm equal or nearly equal to 



