EXTERNAL CHARACTERS. 307 



EXTERNAL CHARACTERS. 



General form and color. — The single specimen of this species was taken in 

 shore collecting at Easter Island. The colored figure upon Plate 1 is repro- 

 duced from a water-color drawing, painted from life by Mr. Agassiz. No notes 

 accompanied the drawing other than the memorandum that the color "should 

 be a Uttle more copper-green." A comparison with other figures of different 

 members of the Dolabellinae, notably those given by Rang (1828), would indicate 

 that this specimen was probably somewhat contracted, and not moving about 

 freely while being painted. In the preserved condition the body-form is bluntly 

 conical, its posterior end being abruptly terminated by an oblique disc from 

 above backward, with prominent smooth and slightly sinuous outlines. The 

 general surface of the body, save for general longitudinal corrugations mani- 

 festly due to shrinkage, is fairly smooth, a few low scattered tubercules being 

 recognizable along the dorsum and in the head-region, as shown in Plate 1. 

 Nothing resembling the highly developed fleshy processes or cirrhi, character- 

 istic of most described species, is present. In this respect it resembles Dolabella 

 ecaudata (Rang) more than any other form. Shrinkage has caused the pos- 

 terior disc to be set off from the otherwise smooth surface of the foot by a deep 

 ditch-like corrugated area. 



The anterior end of the body is bluntly rounded, and is so strongly invagi- 

 nated that the tentacles and mouth-parts are completely introverted into a 

 cavity. From the figure, Plate 1, it is seen that the anterior tentacles are short 

 and bluntly cyUndrical, while the rhinophores are of the same general shape, 

 their bases not close together, but set far forward on the head, more so than in 

 other species. On careful eversion the anterior tentacles are found to be rather 

 narrowly auriculate, while the rhinophores are of the same cylindrical form, with 

 a narrow longitudinal groove upon their outer posterior margin. 



Diviensions. — In the preserved specimen the greatest length of the ani- 

 mal is 16.0 cm., and its greatest transverse diameter is 8.0 cm. The circum- 

 ference at the highest point of the epipodia is 21.0 cm., tapering to 10.5 cm. at 

 the anterior end of the body. The posterior disc is 8.0 cm. in transverse diam- 

 eter, and 5.5 cm. in vertical height, its circumference measuring 25.5 cm. The 

 total length of the epipodial slit is 7.58 cm., its anterior end being nearly mid- 

 way of the body-length. No measurements are at hand of the animal during 

 Ufe, but they were probably considerably greater than those here given. 



