380 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



Color. — When alive a light cartilage gray, when preserved, any 

 color from dirty white to dark grayish brown, according to the kind 

 of preservative used. 



Female. — Cephalic segment small and hemispherical, flattened 

 ventrally; each lateral wing wide and divided at the center into 

 two lobes; neck short, formed of the second segment; third, fourth, 

 and fifth segments much wider than the cephalic segment and so 

 much inflated that the thickness nearly equals the width, with con- 

 cave lateral margins and evenly rounded corners. Third and fourth 



legs in pits on the ventral surface 

 of the trunk; four similar pits on 

 the dorsal surface immediately 

 above these ventral ones; fifth legs 

 lacking; genital segment small, 

 forming with the single abdominal 

 segment a triangle; caudal rami 

 attached to the ventral surface of 

 the abdomen. Total length, 1.5-1.7 

 mm. 



Male. — Cephalic segment as wide 

 as the trunk, its lateral wings not 

 FIGURE 234.-rucca im^ressuB- a Fe- j ^^^ urosome relatively larger 



male, dorsal ; &, female, fourth leg ' . . 



than in the female ; trunk elliptical, 

 with convex lateral margins ; third and fourth legs larger ; fifth legs 

 present on the posterior margin of the trunk, each 1-segmented with 

 three apical setae. Genital segment half the width of the trunk, 

 with a stout hook on the ventral surface at each posterior corner; 

 caudal rami longer than in the female. Total length, 1.2-1.3 mm. 

 Remarks. — This is a fairly common parasite on the southern puf- 

 fer, and is always found on the fins ; it can be recognized by the four 

 pits on the dorsal and ventral surfaces and the three lobes at the 

 posterior end of the trunk in the female. 



TUCCA CORPULENTUS Wilson 



FiGUEB 235 



Tucca corpulentus Wilson, Proc. U. S. Nat. Mus., vol. 39, p. 358, pis. 49, 50, 1911. 



Occurrence. — Found upon the fins of the northern puffer {Sphoe- 

 roides maxyulatus) caj)tured off Marthas Vineyard. 



Distribution. — Found only in the present area. 



Color. — The preserved specimens were a uniform gray. 



Female. — Cephalic segment with its wings divided into four lobes 

 instead of two ; trunk swollen almost into a sphere, as wide as long, 

 with no pits on dorsal or ventral surfaces ; posterior margin without 

 lobes but overhanging the urosome and completely hiding it in dorsal 



