TOO CEYLON PEAKL OYSTER REPORT. 







DESCRIPTION OF THE SPECIES. 



Family: CALIGID^E. 

 Sub-family: CALIGIKdE. 

 Lepeophtheirus brachyurus, Hbllee Plate I., figs. 1 to 10. 



This species was briefly described by Heller in tbe ' Reise der Novara,' 

 1865, and has not been seen by any other investigator since. Heller's specimens 

 were obtained near Java upon the gills of the same host as the present Ceylon 

 specimens. 



The following description, and the figures given on Plate I., supplement as well as 

 corroborate Heller's original diagnosis : 



Female. Carapace ovate, considerably narrowed and rounded anteriorly, widened 

 and emarginate posteriorly. The length of the carapace is more than twice that of 

 the rest of the body, but is a little less than its width. The grooves on the dorsal 

 surface are distinct, with the cross-bar of the H about in the centre of the carapace, 

 while the anterior and posterior halves of the lateral grooves are inclined like the 

 sides of an hour-glass. The frontal plates are narrow, scarcely more than one-third 

 the width of the carapace, with a deep but narrow central incision. The eyes are 

 moderately large and placed far forward, about one-fifth the length of the carapace 

 from its anterior margin. The thoracic area is large and wedge-shaped, three- 

 quarters of the width of the carapace and slightly concave at its posterior margin, 

 less than half the width and slightly convex at the anterior margin. 



The fourth or free thorax segment is very short and concealed in dorsal view by 

 the overlapping carapace. The genital segment is transversely elliptical, one-third 

 wider than long, with evenly rounded sides and a nearly straight posterior margin. 

 The fifth legs are visible at the posterior corners. 



The abdomen is short and narrow, one-fourth the length and one-fifth the width of 

 the genital segment, one-jointed, with the posterior margin wedge-shaped. The 

 anal laminae are minute, fastened to the sides of the wedge, and each armed with 

 three plumose setae and a small spine. 



The egg-cases are about the same length as the entire body and as wide as the 

 abdomen. The eggs are of medium thickness, about 70 in each string. 



Of the appendages, the first antenna? are short and unusually wide, a considerahle 

 portion of the basal joint being concealed beneath the edge of the carapace. The 

 terminal joint is only about half the length of the basal and carries a tuft of spines at 

 its tip. The second antennae are stout and of the usual form, with a long terminal 

 claw bent abruptly near the tip (fig. 2). 



The first maxillae are very small and rudimentary ; the basal portion is swollen and 



