SOALISETOSUS COMMUNIS. 373 



dorsally studded with a series of small papillse or short cilia, and, besides, with a 

 smaller number of much larger clavate processes. The outer and posterior borders 

 of the scale have a close series of short cilia with globular extremities. The 

 transparent scales show the nerve-distribution minutely. They have numerous yellow 

 patches, or are dotted with white specks, or are of a purplish-brown hue, especially 

 at the inner border. The bristles are crystalline in their transparency. The dorsal 

 bristles are slightly curved and not much tapered, have about eight rows of spines, 

 and the tip is notched. The ventral bristles are slender and elongate, the shaft 

 dilated superiorly, and with a spinous frill. From this the spinous region passes 

 with a slight bend to the dorsum, and ends in a well-marked hook with a secondary 

 process apart from its base. The dorsal cirri are rather long, with a slight dilatation 

 beneath the long filiform tip. They have similar cilia to the median tentacle. The 

 ventral cirrus is also rather long, but smooth. 



Synonyms. 



1841. Lysidice communis, Delle Chiaje. Discriz. e not., 'hi, p. 104, tab. 103, f. 1. 



1853. Aphrodita velox, Dalyell. Pow. Creat., h, 169, pi. xxiv, f. 13. 



1864. Polynoe pellucida, Ehlers. Die Borst., p. 105, taf. in, f. 5, 7 — 13 j taf. iv, f. 1 — 3. 



1868. Her madion fragile, Claparede. Ann. Chet. Nap., 73, pi. v, f. 2. 



1869. Lepidonotus pellucidus, Mcintosh. Trans. R. S. E., xxv, p. 408, pi. xv, f. 2. 



1870. Hermadion fragile, Claparede. Supplem., Ann. Chet. Nap., p. 16, pi. ii, fig. 2. 

 1875. „ pellucidum, Mcintosh. Invert, and Fish., St. A., p. 117. 



„ ,, fragile, Marion and Brohretzky. Ann. sc. nat., 1875, p. 6. 



„ „ pellucidum, Marenzeller. Sitz. der k. Akad. (sep. Abd.), 13. 



1880. „ „ Langerhans. Z. f. w. Zool., xxxiii, p. 271. * * % 



1884. „ „ V. Cams. Fauna Medit., 203. 



1886. „ „ G-iard. Bullet, sc. Xord, i, p. 12. 



1888. „ „ De St.-Joseph. Ann. d. sc. nat. (7), v, p. 177, pi. viii, f. 51. 



1890. „ „ Malaquin. Ann. Boulon., 22. 



1891. „ „ Hornell. Op. cit., p. 237. 



Habitat. — Though not abundant it extends from Shetland to the Channel Islands 

 in deep water, in the latter region between tide-marks, and on both the eastern and 

 the western coasts. It ranges to the Mediterranean and Madeira. It is commensalistic 

 on star-fishes (Hornell). 



Head (Plate XXVII, fig. 12). — ■ Yellowish in some, or with white pigment-specks 

 posteriorly and at the eyes ; somewhat trapezoidal, the anterior lobes being smoothly 

 rounded instead of forming the usual peaks. The eyes of each side are placed close 

 together, while the right and left pairs are widely separated and placed far back. The 

 anterior pair are considerably larger than the posterior, and are wider apart. In the 

 British examples no lenses are present in them, but Claparede shows such in the 

 Neapolitan. The median tentacle is somewhat long, slightly dilated below the filiform 

 tip, and with rather numerous short clavate cilia. The lateral tentacles are long with 

 slender filamentous tips, and the column has the same short cilia. The palpi are smooth. 

 The tentacular cirri resemble the median tentacle. The ganglia form two distinct ovoid 

 masses in the head. 



