no. 1404. PARASITIC COPEPODS—CALIGID.E— WILSON. 631 



for an} r particular localit} r , but may be found anywhere from the out- 

 side of the operculum to the tip of the tail. 



When disturbed the males scuttle about over the surface in a lively 

 manner, but the females ordinarily remain quiet. In the aquarium 

 both sexes swim about freely, but the male is the more lively and 

 usually lives longer. They can be kept more successfully than many 

 other species, and do not bother by crawling up out of the water. 

 Females with eggs which are nearly ripe retain the egg strings even 

 under rough treatment, and the nauplii ma}^ be reared successfully. 

 The egg cases are separated rather more than usual at their origin 

 in the genital segment. At first they approach each other rapidly 

 until about their own diameter apart, and then extend backward 

 parallel with each other. They are light colored even when well 

 developed, so that it is difficult to judge of their maturity by their 

 color. This is due to the paucity of pigment in the larvae. 



The National Museum collection includes the following lots of this 

 parasite, from the summer flounder {ParalicJithys dentatus) 6065, 6081; 

 W. 61; W. 62; W. 65; W. 73, all from Woods Hole and vicinity. 



From the four-spotted flounder {Paralichthys oblongus) 1285 (two 

 lots with the same number), 1308, 6040, W. 63; W. 64; W. 67; W. 68, 

 all also from the vicinity of Woods Hole. 



•From an unknown host 4403 from Great Egg Harbor, New Jersey, 

 and W. 66 from an unknown localhry. 



From the horse crevalle (Caranx hippos) a single specimen taken at 

 Woods Hole, W. 69. 



From the garfish {Tylosurus marinus) a single male taken at Woods 

 Hole, W. 70, and from the summer skate {Raja erinacea) a single female 

 at the same locality, W. 71. 



LEPEOPHTHEIRUS DISSIMULATUS, new species. 

 Plate XXII. 



Female. — Carapace orbicular, the width and length almost exactly 

 equal; frontal plates large and well defined. Posterior sinuses shallow 

 and broadly triangular; median lobe fully half the entire width of the 

 carapace, projecting but slightly beyond the lateral lobes and squarely 

 truncated posteriorly, sometimes slightly emarginate. Transverse 

 groove in the center of the carapace, its halves nearly straight lines 

 and inclined toward each other like the sides of a roof. Eyes small 

 and placed well forward. Free thoracic segment short and a little 

 more than one-third as wide as the genital segment, with the base of 

 the fourth legs projecting strongly. 



Genital segment a sphere, flattened antero-posteriorly, its diameter 

 a little more than" half that of the carapace, its dorsal surface over- 

 hanging the ventral posteriorly. From the rounded posterior margin 



