102 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.53. 



nogen layer very thick over the entire inner surface of the genital 

 segment and abdomen. 



Genus habitat. — Muscle borers, penetrating from the outside sur- 

 face of the host into the underlying tissues, usually near a fin; an- 

 chored in the muscles themselves by the cephalic horns, the sur- 

 rounding tissues forming a cyst around the head. 



Type of the genus. — Trifur tortuosus^ monot^'pic. 



{Trifui\ a notorious rascal in Plautus.) 



Remarks. — This genus is so markedly different from the others in 

 the family as to warrant its establishment, even upon the scanty ma- 

 terial here recorded. The trunk is almost exactly like that of 

 Haemohaphes., except that it is relatively much smaller, but the 

 head and neck are totally different and resemble those of Lernaeeni- 

 cus. The entire head, including the horns, and the neck are fully 

 chitinized, instead of being soft, and the thorax segments are so 

 completely fused as to be indistinguishable. The new genus thus 

 combines the characters of the two older genera and becomes a con- 

 necting link between them. All the characters essential for its 

 establishment are present, including the antennae and swimming 

 legs, the only things lacking are the proboscis and maxillae, whose 

 future discovery can not affect the systematic position of the genus. 



TRIFUR TORTUOSUS. new species. 



Plates 20 and 21, figs. 158 to 160. 



Ilost and record of specimens. — Two females with egg strings Avere 

 obtained from the outside of the body near the pectoral fin of Salllnta 

 australis, at Otter Bay, Smith Channel, South America. One speci- 

 men lacked the head and was cleared in clove oil to show the inter- 

 nal anatomy; the other was perfect, except the proboscis, and is 

 made the type of the new genus and species, with Cat. No. 49704, 

 U.S.N.M. 



/Specific characters of female. — In addition to the generic charac- 

 ters already given, the cephalothorax with its horns is fully chiti- 

 nized like Lernaeenicus and Phrixocephalus., but totally unlike 

 Haemohaphes. The long posterior horn is slightly curved, conical, 

 and bluntly rounded at the tip; the lateral horns are smaller and 

 shorter but also conical and blunt. 



The neck is comparatively much thicker than in Haemohaphes and 

 is curved in two or three different directions, chiefly sidewise at 

 right angles to the median plane of the trunl?. It is perfectly 

 smooth, without Imobs or horns, and in the cleared specimen is more 

 than twice the length of the trunk; it does not continue the S-curve 

 but is straight for a very short distance and then turns sidewise. 



