2 (58 CEYLON PEARL OYSTER REPORT. 



The definition of Irma should be modified as follows : 



Proboscis nuda ; palpi biarticulati ; antennas 3 (interdum 2 observatse) ; oculi 4 ; 

 cirri tentaculares 12 ; pedes quasi biremes ; ramus dorsalis vestigialis cum articulo 

 basali cirri dorsalis connatus, setas dorsales capillares gerens aut nullus ; seta? ven- 

 trales composite falcigerse ; acicula? binse. 



The fact of an acicula passing into the cirrophore indicates the primitive biramous 

 nature of the foot in those species where dorsal capillary setse do not occur, exactly 

 as in the analogous case of Podarke, Ehlers. The absence of a median antenna in 

 /. limicola is puzzling, and will remain so until more material is obtained. The 

 species described by me as Oxydromus aucklandicus (' "Southern Cross" Collections,' 

 London, 1902, p. 281) should be transferred to the genus Irma as now defined. 



Family: SYLLIDiE. 



Typosyllis taprobanensis, n. sp. Plate III., figs. 77 and 78. 



Localities : East side of Cheval Paar ; and South-west Cheval Paar, Gulf of 

 Manaar. 



This is a variable species, one specimen seemed to resemble T. variegata, the next 

 T. krohni, the differences being in part substantial, in part due to the fact that the 

 pharynx of the one was on the point of being projected, that of the other was 

 retracted completely. 



Antennae and cirri moniliform ; in the first specimen (length 19 millims., width 

 1'5 millims.) the paired and unpaired antennae were about equal in length to each 

 other and to the palps, the paired rather slenderer than the hnpar, shorter than the 

 d< irsal cirri ; the latter, not deciduous, longer alternating with shorter and slenderer ; 

 the first ventral tentacular cirrus slender, not much longer than the palps ; head 

 transverse, partially concealed below the buccal segment ; pharynx, on the point of 

 projection from the mouth, lined by thick dark-brown cuticle (showing dark purplish- 

 black through the skin) carrying a subtermmal dorsal tooth coloured the same as the 

 chitinous intima ; proventriculus, with about 37 rows, finely tessellated, glistening 

 whitish with delicate flush. 



In the second specimen the median antenna was long, showing 36 joints ; most of 

 the dorsal cirri were lost, that of the 5th setiger showed 42 joints, that of the 

 64th setiger upwards of 30 joints ; the pharynx and proventriculus, seen by trans- 

 parency, exactly resembled those of the first specimen and decided the specific identity, 

 but were differently placed, being retracted ; the pharynx extended from the 7th to 

 the 15th setigerous segment, the proventriculus from the 15th to the 25th setigerous 

 segment ; colour of the first 24 setigerous segments : two brown transverse bands in 

 each segment; total number of segments 150 ; length 30 millims. 



The setas of both corresponded in general characters, differing in a manner shown 

 in the figures (Plate III., figs. 77 and 78). In the anterior segments there are about 



