506 F. W. GAMBLE. 



Q7. Cycloporus papillosus, Lang (54). PI. XXXIX, fig. 2. 



1880. Proceros tubekculatus, Schmidtlein, ' Mittheil. Zool. 



Stat. Neapel/ Bd. ii. 



1881. „ „ Lang, ibid., Bd. iii. 



Length 10 — 14 mm. Body elliptical with blunt extremi- 

 ties. In front the antero -lateral margins are produced to a 

 variable extent as a pair of small, pointed tentacles. The 

 dorsal surface is typically covered with small coloured 

 papillae — absent, however, in the variety Isevigatus. Excepting 

 the margins, the body is opaque. The ground-colour is 

 yellowish-white. The main-gut and its six pairs of branches 

 are brown, red, yellow, &c. In adult specimens they are 

 largely concealed by the genital organs, but reappear on the 

 margin, where their terminations are usually brightly coloured. 

 The colour of the dorsal tubercles is variable and due to pig- 

 ment in the epidermis. When the tubercles are absent their 

 position is indicated by pigment-spots. Thus the colour is due 

 partly to the contents of the gut, to pigment, and to the genital 

 organs. Combinations of these three sources of colour ac- 

 count for the diversity between individuals of the same and of 

 different ages, and appear to be correlated with the substratum 

 (generally species of Leptoclinum and other Ascidians). 

 Three to four black spots are present in specimens of the laevi- 

 gatus variety, round the first pair of secondary gut-branches. 

 (For good descriptions of the appearance of this animal at 

 different stages of growth see Lang, 54, pp. 568 — 571.) 



The mouth, just behind the brain, leads into a conical 

 pharynx, the apex of which is directed backwards and is con- 

 tinued into the long main -gut. From this six lateral pairs of 

 branches arise at right angles, which, after branching and 

 anastomosing freely, end in terminal vesicles opening to the 

 exterior through temporary epidermal pores at the mo- 

 ment of the expulsion of faecal matter. The elongate cephalic 

 group of eyes borders the white area produced by the pharynx, 

 and extends forward beyond the brain. There is also a distinct 

 group at the base and on the ventral surface of the tentacles. 



