Gatty Marine Laboratory ^ St. Andreivs. 17 



and slopes with an unbroken edge downward and forward to 

 tlie mid-ventral line, where a fissure separates the two sides, 

 each of which is produced into a prominent rounded edge 

 which slightly overlaps its neighbour. The adjoining first 

 scute is indented in the middle line, thus giving a character 

 to the i-egion. Whilst, therefore, the collar is largely 

 developed ventrally, a considerable part of the dorsum is 

 devoid of it. De St. Joseph found two pigment-spots (eyes) 

 over the cephalic ganglia. An otocyst occurs on each side 

 at the base of the brauchiae. The branchiae are of moderate 

 length (1 length of body), and their filaments are from 

 eighteen to twenty-four in number. Each filament has the 

 usual structure, and tapers distally, ending in a subulate 

 whitish terminal process, into which the chordoid axis, which 

 is remarkably attenuate towariis the tip, does not go. The 

 subulate terminal filament, where no eye is present, has 

 a translucent thin margin, especially at the commence- 

 ment of its inner edge. It is at this region (viz. the 

 inner base) that the eye develops as a conspicuous dark 

 brownish-violet organ, a stripe of the flattened translucent 

 margin connecting its inner base with the line of the 

 pinnae ; whereas the distal part of the process is slender. 

 The pinnae are of average length, and provided with a 

 chordoid unjointed axis. When injured, these organs are 

 readily reproduced from the filament, to which they give a 

 feathery appearance when the animal projects itself from its 

 tube. The branchiae are gracefully spread like the flower 

 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 

 " couleur 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 had a 

 slightly barred aspect from the arrangement of the white 

 touches. The pinnae 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 oft' between them. 



The anterior region consists of nine segments (six to nine. 

 Be St. Joseph), eight of which bear pale golden bristle-tufts, 

 which slope in the preparations upward and backward, 

 Ann. & Mag. N. Hist. Ser. 8. Vol. xvii. 2 



