8i 



Fam. SABELLID^. 

 POTAMILLA KEXIFORMIS, O. F. Milller. 



1800. Die iiicrciifonnigcn Ainpliifrifc, O. V. ]\Juller, Xaturges. 



Wurmarten, p. 194, Tab. xvi., tigs, i, 2 and 3. 

 1849. Sabclhi iriiifonnis, Leuckart, Arch. f. Naturg. xv, i, 



p. 183, Tab. 3, f. 8. 

 1865. Sahelhi saxicavci, De Quatrefages, Anneles, II., p. 4^7, 



PI XV., f. 1-7. 



1867. Potaiuilhi iriiifoniils, Malmgren, Ann. Polychiet., p. 

 114, Tab. xiii., f. 77. 



1868. Sabclla sax/awa, Mcintosh, Ann. Nat. Hist., 4th Ser. 

 ' II., p. 286, PI. XX., f. 5-8. 



1894. Potamilla rciiifoniiis, De St. Joseph, Ann. Sc. Xat. 8e 

 Ser. XVII., p. 292, PI. xi., fig. 296-298. 



A species which shows a considerable amount of purplish 

 brown pigment on the anterior region of the body and on the 

 bases of the branchiie even in spirit. 



The collar anteriorly has a median furrow on the dorsal 

 surface, with a slightly frilled triangular lobe on each side. 

 The rim slopes obliquely downward and outward, making" a 

 shallow notch on the dorsum before reaching the line of the 

 bristle-tufts. It then curves to the ventral surface, the rim on 

 each side being separated by a median fissure. Dorsallv, a 

 median furrow passes backwards a short distance, not beyond 

 the third bristle-tuft. The anterior region of the body consists 

 of eight segments, marked by the bristle-tufts and pads. The 

 ventral median groove goes forward to the second segment 

 behind the anterior region, then slopes to the right towards the 

 furrow between the anterior and the following region of the 

 body, but is not continued on the dorsum. 



The length of the largest example was 80 mm. hut the 

 posterior region was imperfect. 



The branchiae are about fourteen in number, appear to be pro- 

 portionally short, and the filaments proceed quite to the tip. 

 On viewing the fans from the dorsum, the rachis in several has 

 three distinct pigment-specks, in others one or two, so that the 

 branchiae have a characteristic appearance. The purplish 

 brown specks project from the line of pigment on the anus as 

 globular bodies. Their number is variable, but none liad so 

 many as those described by Langerhans,* (his var. polyopJitJinl- 

 inos with six or seven eye-spots), from Madeira. The branchii\3 

 in the British examples are often speckled green and white. 

 The tentacles are somewhat lanceolate and pointed processes. 



* Zcit. f.w. Zool. Bd. XL., p. 266. 



