278 CEYLON PEARL OYSTER REPORT. 



there are two stout setae, tridentate (one damaged), Avhich are not compound 

 (Plate IV., fig. 100). These clearly represent the acicular setae in the first foot. A 

 parapodium from the anterior half of the body contains three aciculae, a bundle of 

 simple capillary setae, two bidentate acicular setae, and a small bundle of internal 

 capillary setae associated with the dorsal cirrus, passing nearly to the apex of the 

 cirrus. The width of the worm is 3 millims. ; the median antenna stretches back 

 over 7 segments. 



Onuphis holobranchiata, Marenzeller Plate IV., fig. 101. 



Station V., off Chilaw, Gulf of Manaar, 11 fathoms. 



One specimen contained in a membranous tube coiled up between the valves of a 

 Lamellibranch, adhering to one of the valves (Plate IV., fig. 101). The length of 

 the coiled mass was 13 millims. ; calcareous particles adhered to the borders of the 

 tube ; the whitish end of the tube projected beyond the posterior edge of the shell, 

 like a siphon, to the length of 21 millims. ; diameter 2 - 25 millims., a few shell- 

 fragments and other calcareous ddbris attached. No part of the worm protruded 

 from the mouth of the tube. After extraction of the anterior portion of the worm, 

 which broke away from the rest of the body, it proved to be an Onuphid allied to 

 Onuphis holobranchiata, Marenzeller. 



The submedian ceratophores show about 10 annulations and a terminal collar ; 

 they are less than one-fifth the total length of the appendages ; half as long again 

 as the median ceratophore and equal to the lateral. The lateral ceratophores are half 

 the total length of the appendages to which they belong. The median antenna 

 stretches back over 21 segments, but the body has a dorsal flexure in the preserved 

 state ; the submedian antenna? are longer than the median. The frontal antennae are 

 obtusely subulate, coloured brown at the base. The tentacular cirri are shorter than 

 the buccal segment, which is rather longer than the prostomium, and has a concave 

 anterior dorsal border. 



The first four parapodia are porrect, decreasing in size to the fourth, and occupying 

 a ventral position. After the fourth, the line of parapodia bends up in a conspicuous 

 arc to a more dorsal position. The first foot is not greatly enlarged, not longer than 

 the buccal segment ; the dorsal cirrus and posterior ligule are equal and similar and 

 longer than the bulk of the foot. The unifilar branchiae commence on the first foot. 

 The first foot contains a small bundle of fine setae passing to the dorsal cirrus, two 

 aciculae and four tridentate compound setae. A parapodium from the region between 

 the 40th and 50th segments contains, besides the internal setae of the dorsal cirrus, 

 four or five capillary setae, three scalprate or comb setae, four aciculae, and two 

 bidentate acicular setae. 



There are two discrepancies between the above description and that furnished by 

 Marenzeller (' Siidjapan. Ann.,' i., 1879, p. 24), and, in addition, the peculiar 

 character of the habitaculum has not been described before. According to 



