1915] MacCallum: Ectoparasitic Trematodes 403 



The head is formed much Hke that of others of the family, 

 a slight notch at the extreme tip and on each side a row of 

 papillae extending back almost to the pharynx, which is large. 

 The post-pharyngeal esophagus is short and the angle on each 

 side of the pharynx and esophagus is filled with unicellular 

 mucous glands. Anterior to the pharynx are the usual four 

 ocular spots. The vitellaria are plentiful and extend almost 

 from opposite the genital pore to the point posteriorly where 

 the body suddenly narrows to form the disc. The hooks on the 

 disc have their bases attached to the usual two chitinous blocks 

 of yellow material. These are not of the same shape as in D. 

 teuthis or D. longiphallus. 



For the purpose of description, the characteristics of the 

 worm are, that it is small, has a straight tubular disc end, four 

 large hooks and several small ones clustered in the end of the 

 disc, and the cirrus straight and pointed. 



On account of these peculiarities the worm must be con- 

 sidered a new species and the name D. balistes is proposed. 



Measurements of Diplectanum balistes. 



Length 55 mm. 



Width 09 mm. 



Diameter of disc .035 mm. 



Width of head .02 mm. 



Length of cirrus 04 mm. 



Diplectanum longiphallus, nov. sp. 

 (Fig. 136) 



On January 23, 1915, there were found on the gills of a 

 spade fish, Chaetodipterus faber, a colony of Diplectana, which 

 apparently are different from those described heretofore. 



In general appearance they are like those found on the 

 surgeon fish, (Teuthis hepatus) and in Balistes Carolinensis, or 

 trigger fish, but in detail the anatomy is somewhat different. Like 

 them it is small; being only about 1 mm. long by .15 mm. wide. 

 The clinging disc seems in general form the same in almost all, a 

 firm terminal mass with four relatively large, strong hooks at- 

 tached to odd shaped chitinous blocks, which serve to support the 



