250 BRANCHIOMMA VESICULOSUM. 



of a Convolvulus (Claparede). De St. Joseph describes the exterior of the branchiae as 

 white, or as brownish violet, or alternately of these colours. Sometimes they are entirely 

 "eoloeur de rouille ou gris de souris." In the examples from Plymouth the colour was 

 pale olive throughout, only the exterior of the filament being marked by an interrupted 

 band of white, which broke up distally into isolated touches. The remarkable delicacy of 

 the pinnae is characteristic, each branchial process thus resembling a feather with its 

 delicate barbs. When viewed from without the branchial fan has a slightly barred aspect 

 from the arrangement of the white touches. The pinnse are pale olive throughout. The 

 eyes vary much in size on the same specimen, and in one case only a single large one 

 was present, the rest being small — in varying degrees. All are double, with the terminal 

 process passing off between them. Such therefore differs from the single eye of the 

 Branchiomma described by Brunotte 1 and others, in which the crystalline bodies are 

 arranged in a radiate manner round the central axis. The minute structure of each, 

 however, would appear to be similar to that first described by Kolliker 2 and afterwards 

 by De Quatrefages 3 and Ohatin, 4 a figure from the var. Kollikeri being given in Plate 

 CXXXVIII, fig. 4. 



1 ' Recherches Anat. Branchiomma/ pp. 37 — 45< 



2 'Zeitschr. f. wiss. Zool./ Bd. ix. 



3 f Ann. Sc. nat./ 3 e ser., t. xiii, 1859. 



4 Ibid., 6 e ser., t. viii, 1878. 



