NO. 4 WILSON: PARASITIC COPEPODS 25 



restore in full the original recognition, add a new host and two new 

 localities, and afford some information with regard to development, 

 since the females of the Colombian species were only half grown. 

 Accordingly a figure and description of one of these young females 

 are here included (plate 3, fig. 2). 



Young Female. Carapace a little longer than wide and about 

 two thirds of the entire length; frontal plates wide and prominent, 

 the lunules projecting as much as in the adult. The posterior median 

 lobe is not much wider than the lateral lobes but projects consider- 

 ably behind them. The lateral lobes curve inward as in the adult 

 and are more angular at their outer corners. The free segment is 

 two thirds as wide and almost half as long as the genital segment 

 and is not contracted posteriorly. The genital segment is obovate, 

 considerably narrowed anteriorly and a little wider than long, and 

 is less than half its adult size. Its posterior margin is rounded instead 

 of scalloped and it carries rudiments of a fifth pair of legs at its 

 posterior corners. The abdomen closely resembles that of the adult 

 in shape and proportion and already shows signs of segmentation 

 in the form of lateral indentations. The appendages are the same as 

 those of the adult except that the fourth legs appear larger and reach 

 behind the posterior margin of the genital segment. 



Caligus constrictus Heller (plate 3, figs. 3, a-i.) 

 Caligus constrictus Heller, Reise der Novara, p. 175, pi. 15, fig. 5, 1865. 



Heller established this species upon a single male specimen taken 

 from the gills of a Stromateus species in the Indian Ocean, and no 

 other specimens have ever been reported. The present collection 

 includes 2 females from the gills of Caranx hippos (Linnaeus), at 

 Secas Island, Panama, a single female from the gills of the same 

 host at San Francisco, Ecuador, and 4 females from the gills of a 

 runner, Elagatis bipinnulatus (Quoy & Gaimard), at Bahia Honda, 

 Panama. These 7 specimens are referred to Heller's species because 

 they certainly are not identical with any described Caligus females. 

 And they agree so closely in structural details w^ith Heller's male as 

 to preclude any idea of creating a new species for them. They thus 

 confirm the establishment of Heller's species and complete the 

 species diagnosis by supplying the female. 



Female. Carapace orbicular, slightly wider than long; frontal 

 plates with a nearly straight anterior margin, scarcely indented at 



