LYSILLA LOVBNI. 203 



Genus CLVIII. — Lysilla, Malmgren, 1865. 



Cephalic lobe forming a wide frill to the oral region and assuming various outlines 

 according to the degree of expansion or contraction, its edges being somewhat thinner 

 than in Polycirrus and prolonged ventrally. A slight dorsal collar. The surface of the 

 cephalic plate has numerous clavate, grooved tentacles along the dorsal and lateral 

 regions, but with a cluster of tangled filiform ones on each side ventrally. Neither eyes 

 nor branchiae. The buccal surface is prolonged ventrally as a tongue-shaped process 

 fixed anteriorly but free posteriorly, and with a thickened glandular area (scute) in the 

 centre. The body is enlarged anteriorly with a convex dorsal region, and two projecting 

 and rounded ventrolateral regions. The whole of the anterior dorsal surface as well 

 as that of the swollen ventro-lateral regions is minutely tuberculated, the tubercles on 

 the swollen ventro-lateral regions being larger, the papilla?, moreover, from intervening 

 lines, having a transverse arrangement, but posteriorly the body appears to have only 

 smooth rings, and it tapers to the caudal extremity. Segments indistinct. Six pairs 

 of small setigerous processes in the groove between the dorsum and the ventro-lateral 

 projections. Bristles simple and short. No uncinigerous processes or hooks ; the anterior 

 nephridia are larger than the posterior. 



1. Lysilla Loveni, Malmgren, 1865. Plate CXX, figs. 13 and 13 a— lateral and ventral 

 views of body ; Plate CXXVII, fig. 3— bristle. 



Specific Characters. — Cephalic region as in the genus. Body 30 — 60 mm. long, with 

 indistinct segmentation, though posteriorly twelve deeper sulci indicate segments, dilated 

 and papillose or tubercular anteriorly, the largest tubercles being on the ventral surface 

 of the lateral ridges (nephridial papillae). Six pairs of setigerous processes, beginning 

 on the third segment, with curved ends anteriorly, each containing a simple closely 

 arranged fascicle of pale bristles, the tips of which are curved and terminate in the tissues. 



Nephridia occur in the six bristled segments (Hessle), and their pores are on short 

 cirriform papillae. 



Synonyms. 



1865. Lysilla Loveni, Malmgren. Nord. Hafs. -Annul., p. 393, Tab. xxv, fig. 71. 



1867. „ „ idem. Annul. Poly ch., p. 111. 



1869. „ „ Mcintosh. Rep. Brit. Assoc. (1868), p. 338. 



„ „ „ idem. Trans. Roy. Soc. Edin., vol. xxv, p. 424. 



1873. „ „ Kupffer. Jahresb. Komm. deutsch. Meere, p. 152. 



1874. „ „ Malm. Annul. Goteb., p. 99. 

 1879. „ „ Tauber. Annul. Danica, p. 134. 

 1883. „ „ Levinsen. Vidensk. Meddel., p. 172. 



1897. „ „ Michaelsen. Polych. deutsch. Meere, p. 176. 



1912. „ „ Wollebgek. Skrift. Yid.-selsk. Krist., No. 18, p. 75, pi. xvi, figs. 1—4. 



„ „ „ Meyer, A. H. Inaug. Dissert. Kiel, p. 54. 



1917. „ „ Hessle. Zool. Bidr. Uppsala, Bd. 5, p. 230. 



„ „ „ var. Macintoshi, idem. Ibid., p. 231. 



