PALLASIA MUKATA, N. SP. : A NEW BKITISH SACELLAlilAX. 303 



such filament is also attached to a small projecting piece behind the 

 first rudimentary tooth. The neuropodial cirri are developed on the 

 abdominal segments as flattened, bilobed processes arising behind the 

 bundles of neuropodial chaitffi and joined to the ventral edges of the 

 notopodia. Of the two lobes of each cirrus the internal is rounded, 

 the external conical and pointed ; the bilobed structure becomes less 

 pronounced posteriorly. Each neuropodium has a bundle of long, hair- 

 like cluette, which are longest on the most posterior segments and show 

 the structure seen in Fig. 7. 



The smooth, caudal portion of the worm is devoid of appendages, 

 excepting for three or four pairs of rudimentary neuropodial cirri 

 on its most anterior part. The anus is terminal and is surrounded by a 

 large, funnel-shaped membrane with a crenate margin. 



JDimcnsions. Total length of preserved specimen, 13 cm. (5-1 inches). 

 Length of first segment to the tip of the peristomial lobes, 22 mm. 

 Length of thorax, to anterior edge of mouth, about 19 mm. Length of 

 abdomen, ^6 mm. Length of caudal portion, 26 mm. Maximum breadth, 

 not including parapodia, 10 mm. Length of tentacles, 18 mm. 



Amongst the various species of Sabellaridie (Hermellidic) which have 

 been described, the two species which most nearly resemble that now 

 found at Plymouth are SahrUarii/ {Pidlasia) Giardl, Mcintosh 

 (from Port Jackson, Sydney), which Mcintosh thinks may be identical 

 with Kinberg's L>/(/domis indicxs, and SaheUarla {Pallasia) IccvispinU, 

 Grube (from Upolu and Ascension). The three species P. Icvvispinis, 

 P. Giardl, and P. murata form a distinct group of the genus Pcdlasia 

 cliaracterised by the deep division of the peristomial lobes (a char- 

 acter found also in P. Johnstooii, Mcintosh), l)y the straight, slender 

 and pointed palea3 of these lobes, and by the fact that the dorsal chcctte 

 of four segments (Segts. 3, 4, 5, and 6) have the modified, stout, 

 flattened form, instead of this modification being confined to three 

 segments only. 



The following table gives an indication of some of the points in 

 which the tliree species differ from one anotlier : — 



Length (preserved) 

 ]ire;ulth . 



Number of Segments . 

 Papillae on Peristomium 



Paleae- 



Uncini 



-outer row 

 inner row 



P. Iccvispinis, 

 Grube. 



25 -f mm. 

 4-5 



27 



16 



28, straight and smooth 



6 teeth 



18 fiicli si(k' 



P. Giardi. 

 Mcintosh. 



7 mm. 

 2 „ 



11 



P. murata, 

 n. sp. 



130 mm. 



10 „ 



46 



20 



rDenticulate at tip,y 3 ^^^^.^^^ ^^^^^ ^^^^^^^^ 

 y sliglitly curved j ' ° 



Curved inwards 1 1 „ „ 



9 teeth 8 teeth 



l'O •_>! rarll Mile 



