272 CEYLON PEARL OYSTER REPORT. 



of hemigomph instead of homogomph spinigers in the inferior ventral fascicle is 

 sufficient to indicate fundamental divergence is interesting. The third tentacular 

 cirrus stretches back to the end of the seventh segment as in N. tmfasciata. 



Nereis ehlersiana, Grube. (Grube, 'Ann. Semp.,' 1878, p. 71.) 



Locality : Station LXIX., Chilaw Paar. 



The anterior portion of the body comprises 15 segments (14 setigerous) ; the dorsal 

 cirri of the first seven setigerous segments are modified, unequally elongate and 

 foliaceous. A normal parapodium from the anterior region shows reduced rounded 

 ligules, moderate dorsal cirrus much longer than its ligule, short ventral cirrus ; 

 dorsal seta? homogomph spinigerous ; superior ventral homogomph spinigers and 

 heterogomph falcigers ; inferior ventral heterogomph falcigers. 



Ceratonereis falcaria, n. sp. Plate IV., fig. 89. 



Locality : South-west Cheval Paar, two specimens. 



About 107 segments with an even diameter of 2'5 millims. up to the region of the 

 55th segment, then rapidly attenuating ; length 27 millims. Frontal border notched 

 so that the antenna? are borne upon ceratophores as in C. tentaculata, Kbg., and 

 C. excisa, Gr, Eyes large, in a rectangle. Tentacular cirri moderately long ; dorsal 

 cirri more than twice as long as the dorsal ligules ; ventral cirri of the two middle 

 quarters of the body with basal lobules. 



The distinctive character of the species is afforded by the setre. In the first 

 sixteen segments the setse of the dorsal fascicle are homogomph spinigerous ; of the 

 superior ventral fascicle homogomph spinigerous and heterogomph falcigerous ; in the 

 inferior ventral fascicle heterogomph spinigerous and heterogomph falcigerous ; the 

 shafts are striated, the appendices fringed and the falciform appendices are simple, 

 not bidentate. After this the dorsal seta? undergo a change, becoming homogomph 

 falcigerous with a deeply set, strongly bidentate appendix without guard (Plate IV., 

 fig. 89). Transitional forms between the two kinds of dorsal setse are to be observed, 

 namely, seta? in which the appendix is shorter and stouter than in the normal 

 spinigerous setse. Paragnaths : I., 0; II., 5-5; III., 7 (in one row); IV, 10-10. 

 Maxilke with about six denticulations. In the character of the paragnaths this 

 species approaches C. vulgata, Ktnberg, from Honolulu. The change of dorsal setse 

 from spinigerous to falcigerous is remarkably diagnostic. 



Ceratonereis pectinifera, Grube Plate IV, figs. 90 and 91. 

 Grube, 'Ann. Semp.,' 1878, p. 66. 



Locality : South-east Cheval Paar. 



A small Nereid, 17 millims. in length, almost the only one in the collection with 

 the proboscis extruded. The systematic importance of the paragnaths of Nereidse is 

 well known, and a particular illustration of it is afforded by this species in comparison 



