SYLLIDJE. 23: 



Family IX. — Syllim-, continued. 



By the careful search of the tidal region at Torquay, Major E. V. Elwes has made a 

 notable addition to the Syllidge of Britain since the issue of the last part. He followed 

 the plan of immersing roots of tangles and similar growths from the rocks in sea-water, 

 when the Syllids crawl to the water-line and are thus easily removed for examination. 

 Major Elwes kindly forwarded such preparations as he had made, and has thus 

 rendered it possible to include them in the present part. Should living forms be in 

 future obtained they may yet be represented in the work. The success of this observer 

 indicates what may yet be accomplished in the group by skilful and persevering 

 search in suitable localities. Further knowledge of the development of the Syllids has 

 been gained by Mr. Gravely, 1 who found a pelagic stage probably of Odontosyllis gibba,oS 

 Port Erin, Isle of Man. He also gives an account of three larvse which he connects 

 with Syllids, 2 his A, B, and C respectively, from the same locality, but further 

 examination would appear to be necessary. 



The notice of these also affords an opportunity for reference to the remarkable 

 aberrant form Iclithyotoinus sanguinarius, found by Lo Bianco on the Neapolitan eel, 

 Myrus vulgaris, and ably described and figured by Eisig 3 and referred by him to the 

 Syllids. It is apparently a more modified condition of parasitism than that detailed 

 on p. 140, vol. ii, where a parasitic Autolytus, found by C. Crossland at Wasin, 

 East Africa, fixes itself by its permanently extruded proboscis to Nemerteans and Poly- 

 chaets. Ichthyotomus is attached by two stylets to the median fins of the eel, and 

 resembles a broad Syllid, measuring from 5 to 7 mm. in length, or in the case of a 

 ripe female to 10 mm., and having from seventy to eighty segments. The head is round 

 and truncated, with indications of median and lateral tentacles, a minute pair of eyes 

 posteriorly, rudimentary palpi, a ciliated (nuchal P) groove on each side in front, and a 

 pair of tentacular cirri on the first segment. The body ends posteriorly in a tapered 

 tail with a pygidium, at the tip of which are the anus and two cirri of moderate 

 length. The remarkable boring apparatus recalls the armature in the mastax of 

 certain rotifers, and consists of two twisted blades with serrated edges, sharp points, 

 a "locking" apparatus of the stem, and a posterior bifid process fixed to the complex 

 muscular proboscis in the centre of a cup-like sucker. The proboscis is globular or 

 ovoid, and is followed by a second globular region which Eisig considers to be the 



1 ' Quart. Journ. Micros. Sci./ N.s. ; vol. liii, p. 600, 1909. 



2 f L. M. B. C. Memoirs/ xix, Polycli. Larva?, pp. 4—10, pi. i, figs. 1—5, 1909. 



3 ' Fauna u. Fl. Neapel/ Monographie xxviii, 10 pis., 1906. 



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