112 FLABELLIGERA AFFINIS. 



at a series of spirit-preparations both bristles and hooks have a tendency to point down- 

 ward with varying degrees of obliquity. 



De St. Joseph describes two long white segmental organs in the seven or eight 

 anterior segments, also two eyes (each of two coalesced) over the brain, and six pairs of 

 genital glands anteriorly. 



This is one of the most beautiful members of the group, for it is enveloped, as it 

 were, in a fairy covering of gauze or lace, the pale bluish lustre of which enhances the 

 effect of its fine colours and resplendent bristles and hooks. The bluish hue is stated by 

 Claparede to be due to the granulations in the papillae, the papillae helping to keep 

 the animal, surrounded as it is by its translucent investment, in touch with the outer world. 

 Habits. — When lodged in the crevices of Filograna implexa considerable difficulty is 

 experienced in extricating it without rupture, since it clings tenaciously to its surround- 

 ings, and even avoids exposure of its body where its retreat can be intercepted. 

 Occasionally it swayed the body to and fro in a glass vessel without moving from the spot, 

 or in other cases, and as Dr. Grieve, of Glasgow, long ago noticed, it swam in a vessel of 

 sea-water with considerable facility. Frequently the body is contracted from behind 

 forward, and the frontal fans of bristles bend over the green branchiae when danger 

 appears imminent. Though not gifted with powers of rapid locomotion on the bottom, 

 yet it frequently climbs on Cerawium rubrum and other sea-weeds, and having settled in 

 a comfortable position, which it can so readily do by means of its fine hooks, the anterior 

 end is thrust in various directions whilst the frontal fans are expanded and the yellow 

 palpi search and feel constantly all around, indeed, the body is seldom at rest anteriorly. 



Reproduction.— In July and August many of the examples, and a few of these were 

 small, procured between tide-marks and dredged off shore in the Channel Islands, and 

 those obtained in the latter month in Lochmaddy, had the body-cavity crowded with 

 ova, which in the preparations retain a greyish-brown hue or just a trace of madder- 

 brown. These are apparently nearly ripe and with a tough capsule, so that the breeding 

 season is nigh. In some they fill the coelom from the dorsal to the ventral surface, only 

 a brief area at head and tail respectively being free, and they give a characteristic 

 firmness and rigidity to the body. In others, and some of these were small, masses of 

 what seemed to be nearly ripe sperms occurred as whitish masses which gave the body 

 a distinctly segmented appearance, apart from the feet and their bristles. Coloration, 

 therefore, at this season, readily distinguishes the sexes of the mature examples. 



Daly ell 1 notes that a quantity of green spawn once appeared in a vessel containing a 

 specimen in the beginning of June. 



De St. Joseph (1894) observes that the ova are brownish or greenish-brown. 



Krukenberg 2 again describes generally the greenish pigment in the ova of Siphonp- 

 atoma diplochaitos. 



Montagu 3 (1808) has a coloured figure of this species, but appends no name. 



In 1820 A. G. Otto 4 gave a structural description of Siphostoma diplochaitus in which 



1 f Pow. Creat./ vol. ii, p. 257. 



2 < Vergl.-Phys. Stud.,- 2 Eeihe, 3 te AUh./ p. 6, Heidleberg, 1882. 



3 MS. vol. (1808) Linnean Soc, pi. Mi. 



4 ' De Sternaspide et Siphon ostomate, Vratislavias/ 1820, 



