280 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [574] 



ARGULUS LATICAUDA Smith, sp. nov. (p. 452,) 



Carapax orbicular, longer than broad; antero-lateral margin with a 

 deep sinus from which a deep sulcus extends to the center of the cara- 

 pax; sinus of the posterior margin about twice as deep as broad, 

 extending a little less than a third of the length of the carapax. Eyes 

 large. Body scarcely projecting beyond the posterior margin of the 

 carapax. Tail orbicular, slightly longer than broad, its posterior sinus 

 narrow, extending scarcely a fourth the length. Antennula 1 and antenna 

 much as in A. Catostomi, to which the species bears considerable resem- 

 blance. The squamiform appendage upon the base of the prehensile 

 legs expands into a broad posterior margin, which is divided into three 

 broad, closely approximated lobes, of which the extremities are broad, 

 truncated, and slightly and irregularly excavated; the terminal portion 

 of the leg is much as in A. Catostomi, the ultimate segment longer than 

 the penultimate and armed at the tip with two claws. Natatory legs 

 short, the anterior ones not projecting beyond the carapax. 



In alcoholic specimens most of the carapax is opaque and black with 

 a thick deposit of pigment. 



Length of entire animal, in the largest specimen, 5 111111 ; length of 

 carapax, 3.7; breadth of carapax, 3.2; length of tail, 1.3; breadth of 

 tail, 1.1. 



Found among algae in Vineyard Sound. 



A small specimen taken at surface early in September had the opaque 

 portions of the carapax dark brown in life, and in alcohol it retains 

 about the same color. 



ARGULUS LATUS Smith, sp! nov. (p. 452.) 



Carapax large, orbicular, broader than long; the antero-lateral border 

 ' with a broad shallow sinus; the sinus of the posterior margin not 

 deeper than broad, its depth scarcely more than a fifth of the length of 

 the carapax. Body projecting considerably beyond the posterior margin 

 of the carapax. Tail a third as long as the carapax, about two-thirds 

 as broad as long, the lateral margins slightly curved and nearly parallel, 

 the sinus very broad and extending more than a third of the whole 

 length. Disks of the sucking legs about a fourth as wide as the carapax. 

 Squamiform appendage upon the base of the prehensile legs with a pap- 

 pilose area upon the expanded distal portion, the posterior margin 

 without teeth or lobes, but the outer margin of the expanded portion 

 armed with numerous very small teeth ; ultimate segment longer than the 

 penultimate, and apparently without any hooks at the tip. Natatory 

 legs all long, even the anterior projecting beyond the sides of the 

 carapax. 



Color of alcoholic specimens yellowish white. 



Length, 3.0 mm ; length of carapax, 2.2; breadth of carapax, 2.5 ; length 

 of tail, 0,7; breadth of tail, 0.45. 



Taken at the surface, in Vineyard Sound, July 1. 



