402 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



plates, 1.375 mm.; of third plates, 1.65 mm.; width of third plates, 

 3.4 mm.; length of sixth segment plate, 1.65 mm.; length of egg- 

 strings, 13 mm. 



Color a rich creamy yellow, the dorsal surface of the carapace and 

 of the second and third pairs of thoracic plates a deep chocolate 

 brown, a light and transparent spot being left around the eyes, much 

 the same as in crancMi. 



{hicolor, hi, or his, two, and color, colored.) 



Male. — Carapace orbicular, a little more than one-third the entire 

 length on the mid-line, wider than long. Frontal plates wide and 

 prominent, with a broad and shallow central sinus; posterior lobes 

 wide and bluntly rounded. Second thorax segment about filling the 

 space between the posterior lobes; third and fourth segments nar- 

 rowing regularly, the fourth segment of peculiar form, like an inverted 

 flask, the anterior half twice the width of the posterior. Genital 

 segment elliptical with two pairs of rudimentary legs, one at the 

 posterior corners and the other some little distance in front of them 

 on the lateral margins; the two pairs about the same size and simi- 

 larly armed. Abdomen two-jointed, joints equal; anal laminae large 

 and broad, armed with four setae, all about the same length. Ter- 

 minal claws on the second antennae longer and more powerfid than 

 in the female, with two accessory spines. Second maxillipeds with a 

 distinct claw in place of the knob-like forceps. All the legs biramose, 

 the rami two-jointed and armed with stout plumose setae. 



Total length, 6 mm. ; length of carapace on mid-line, 2.1 mm.; width 

 of same, 2.6 mm.; length of free thorax, 1.65 mm.; length of genital 

 segment, 1.2 mm. 



Color, yellow slightly tinged with brown. 



This species possesses peculiar interest, because it is the one on 

 which Leach founded the genus Pandarus in 1816. But he gave 

 practically no distinctive characters for the two species which he 

 presented, the only differences cited being a black pigment in the 

 ''shell and the middle of the abdominal lamellae" of hicolor, the first 

 and therefore the type species, while hoscii, the second species, had 

 a pale body devoid of pigment. There was also a trifling difference 

 in the length of the egg-tubes. From the figures given by Leach of 

 these two species on Plate XX of his 1816 article it is evident that 

 they are identical and that the species named hoscii is simply a young 

 female hicolor in which the pigment has not yet been formed. 



This is shown by an identity of structure so great that Leach pre- 

 sents but a single set of figures to illustrate the appendages of the 

 two species, and by a little difference in size, hicolor being larger and 

 having longer egg-strings, as would naturally be expected. This 

 same condition is often noticed in sinuatus, and, in fact, in all the 

 pigmented species ; the younger and immature forms usually have no 



