PIONOSYLLIS LAMELLIGERA. 237 



Synonyms. 

 1886. Plonosyllis lamelligera, Dj St. Joseph. Ann. Sc. Nat., T ser., t. i, p. 163, pi. viii, figs. 30—38. 

 1908. „ „ Blwes. Journ. M. B. A., n.s., vol. viii, p. 198. 



Habitat. — Common amongst Laninarian roots between tide-marks at Torquay (Blwes). 



Between tide-marks at Dinard, France (De St. Joseph). 



Head rounded in front with four eyes in a trapezoid, the anterior pair the larger 

 and wider apart, and all furnished with lenses. Besides, a pair of smaller black specks 

 occur near the anterior border. Three tentacles, a longer median, and two shorter 

 lateral, are attached to the head, and whilst the basal region of each is smooth, the distal 

 is moniliform, a result to some extent of the mode of preparation. In life De St. Joseph 

 found them hirsute with palpocils. The palpi are large, oblong in life (De St. Joseph), 

 but ovoid in the preparations, soldered at the base (De St. Joseph), though in the 

 preparations this could not be made out. The buccal segment is separated from the 

 head by a brown bar, and on each side are two tentacular cirri, a longer dorsal and 

 shorter ventral. 



The slender body is very little tapered anteriorly, but posteriorly it gradually 

 diminishes to a slender tail which has two anal cirri. The length is 6 — 7 mm., and the 

 number of bristled segments varies from forty-five to fifty-five, the anterior being less 

 distinctly separated than the posterior. It is more or less translucent, marked by three 

 violet bars on the dorsum of each segment (De St. Joseph). 



The proboscis has ten soft papillae anteriorly, and a large tooth. The proventriculus 

 has from twenty-two to twenty-five rows of points, and the stomach follows with two 

 lateral pouches. Abutting on the anterior circle of papillae in the proboscis is on each side a 

 glandular tube, enlarged into a sac on reaching the level of the proventriculus, and filled 

 with little "pits " like those in Eusyllis (De St. Joseph). 



The foot (Plate LXXXVII, fig. 11) presents dorsally a moderately long cirrus, 

 which, though slightly crenate distally, does not present in the preparations the moniliform 

 condition of the cephalic and buccal appendages. The setigerous process is bluntly 

 conical, and bears a series of rather small translucent compound bristles, the tips of 

 which vary from the inferior series with short bifid tips to those at the dorsal edge 

 of the fascicle with much longer and apparently minutely bifid tips (Plate LXXXVI, 

 fig. 12). The condition is thus parallel w r ith that in the Syllis cornuta of H. Ratlike, 

 though none of the shorter series in the latter corresponds with the structure in 

 Pionosyllis lamelligera. Moreover the spines are much stouter in 8. cornuta, and have 

 not the modification of the tip indicated by De St. Joseph, though it cannot be said that 

 this condition has actually been seen in the mounted examples. The ventral cirrus is 

 a somewhat lanceolate structure with large hypodermic reticulations. 



Reproduction. — De St. Joseph mentions that reproduction is direct, and that when the 

 sexual elements are ripening the four posterior eyes increase sensibly in size. In the 

 female grey or violet eggs appear from the fifth or sixth to the ninth segment from the 

 posterior end. All the segments bear swimming bristles, and the intestine atrophies. 

 Similar changes occur in the male ; only those segments filled with sperms have a trape- 

 zoidal form and a rose-orange hue. There are eighteen pairs of brownish testes (De St. 

 Joseph). 



