2 PEOCEEDIXGS OF THE NATIONAL MUSEUM vol. G6. 



end are provided with a thin, rounded, projecting appendage, concave 

 on its anterior face (fig. 2). They taper somewhat, and at the distal 

 end are provided with two rather blunt, recurved hooks on the 

 ventral side. In the left spicule one hook is larger and forms the 

 end of tiie spicule and the other is located just a very little anterior 

 and to one side. The right spicule is likewise terminated by a hook, 

 which is the smaller, and the other is located considerably further 

 forward. Length of spicules 131-156[;,, maximum width 29[jl. The 

 gubernaculum (figs. 1 and 2) is roughly boat-shaped when seen from 

 the dorsal aspect, but from the side it consists of a roughly triangu- 

 lar body with a narrow, curved, slightly tapering process extending 

 anteriorly from the antero-dorsal angle ; length 74^86[;^, width 21-38[ji.. 

 Female. — The maximum width is in the posterior region of the 

 body. Anteriorly the body tapers gradually to a thin filament, pos- 

 teriorly to a fine point (fig. 3). Anterior end rounded. Length 8.7- 

 9.25 mm., maximum width 106-177[jt., width of head 16[j,. Anus 141- 

 164[i. from posterior end, vulva 1.6-1.7 mm. froui posterior end. 

 Oesophagus same shape as in male. Length 816-955[ji,, maximum 

 with 37[x, nerve ring 13 1[;. from anterior end. 



The vulva is a crescentic slit lying apparentl}' in. a lateral (left) 

 instead of a ventral position with the long axis directed longitudi- 

 nally. Well-developed ovijectors are present (fig. 4). 



Ova present in the ovijectors were studied. They are ellipsoidal, 

 surrounded by a very thin shell, and are in process of segmenting, 

 the cell mass filling the entire space within the egg. Size 57-66ix long 

 by 33-40pL broad. 



The type specimen has been deposited in the Helminthological Col- 

 lections of the L^. S. National Museum, where it is registered as No. 

 7804. Paratypes are also included and are entered as 7805. 



This species resembles somewhat T. retoi'tGefonnis^ but differs in 

 the size and shape of the spicules and gubernaculum, size of the eggs, 

 and various other characters. 



EXPLANATION OF PLATE. 



Tricltostrouf/iiJus affiiiis, new species 



All drawinirs made with a camera lucida. 



Fig. 1. Dorso-lateral view of bursa .showing dorsal ray, left externo-dorsal 

 ray, and all six rays in right lobe of bursa. Spicules and gubernacu- 

 lum shaded X 345. 



2. Spicules and gubernaculum X 345. 



,',. Posterior end of female X 395. 



4. Oviiectors of female, vulva not shown, X 170. 



o 



