4o8 WHITMAN. [Vol. IV. 



a yellow vitta commences at the anterior extremity, and is more 

 or less elongated, in some specimens less than one-fourth the 

 length of the body, and in others extending nearly, or quite, to 

 the posterior disc ; lateral margin with eighteen or twenty sym- 

 metrical, equal, and equidistant quadrate yellowish spots ; pos- 

 terior disc above radiate with yellowish ; ocular points two, 

 appropriate, sometimes apparently confluent ; beneath very flat, 

 whitish, with about eleven longitudinal lines ; lateral edges very 

 acute. 



" Length, in a state of repose, two inches ; greatest breadth, 

 seven-tenths of an inch." 



According to Verrill : " This species is one of the largest 

 and most conspicuously colored of the genus. 



"Body smooth, but distinctly annulated, much depressed, 

 broad, tapering anteriorly to the obtusely rounded head, broad 

 and emarginate posteriorly, with a broad, round, posterior sucker 

 or acetabulum, about half of which is exposed behind the end of 

 the body. Length, in extension, three inches ; greatest breadth, 

 three to five tenths of an inch, according to the degree of exten- 

 sion. Ocelli usually united into one inconspicuous spot, placed 

 near the anterior margin of the head ; two or three other minute 

 black spots, somewhat resembling ocelli, sometimes occur along 

 the margins of the head anteriorly. 



" Upper surface variegated with green, yellow, and brown ; 

 the ground-color is usually dark greenish brown, with a broad 

 median vitta of pale greenish yellow, which at intervals expands 

 into several large, irregular spots ; unequal, oval, and rounded 

 spots are also irregularly scattered over the back. The entire 

 margin is surrounded by a series of alternating square spots of 

 dark green and yellow. Lower surface longitudinally striped 

 with numerous purplish brown and black lines ; the margin 

 spotted like that of the upper side." 



These descriptions give us the size, shape, color, number of 

 eyes, and locality. Size and shape do not help us much, since 

 they vary so much, and since so many species are so nearly 

 alike in these respects. The eyes are a very constant feature ; 

 but a number of distinct species agree in having only one pair 

 of eyes closely approximated near the anterior margin of the 

 head. The localities are so widely separated that they speak 

 against rather than for identity. Color, as every one knows 



