LEPTONEREIS GLAUCA CLPDE. AND GENUS I.EPTONEREIS KINBERG. 245 



There can be little doubt that Leptonereis must occur commonly in 

 many localities on the shores of this country and of the Continent in 

 which its presence is not suspected, either for lack of observers or on 

 account of its small size. 



GENUS LEPTONEREIS KINBERG, CHAR. EMEND. 



Proboscis furnished only with soft papillae. 



The notopodium and neuropodium rather deeply divided. 



In the male heteronereid, the body is divided into three distinct 

 regions, the middle region only being modified for swimming, while the 

 posterior is marked by the appearance of peculiar fused setae, not present 

 in the nereid-form or in the female heteronereid. 



Characters otherwise as in Nereis Lin. 



Leptonereis glauca Claparede, Plate I, Figs. 1-10. 

 Leptonereis glauca Claparede, 3, p. 90, PI. 7, Figs. 3-3c. 



vaillanti de St. Joseph, 6, p. 246, PI. 10, Figs. 113-123 ; 

 PI. 11, Fig. 124. 

 ,, vailla7iti Elwes, 8, p. 351. 



vaillanti Mcintosh, 8, p. 264, PI. 86, Figs. 9-9a. 

 ? Leonnates pusillus Langerhans, 5, p. 279. 



This little nereid occurs in some numbers on the piles of the wharf at 

 the Great Western Docks. These are exposed at low water, and are 

 covered with compound ascidians, sponges, various coelenterates and 

 other sedentary organisms, which, together with the muddy sediment 

 which accumulates in such places, form a thick encrustation on the 

 cement piles and wallings near low-water mark. In these congenial 

 surroundings Leptonereis dwells. It also occurs in dredgings from Asia 

 Shoal and the Cattewater, in the former of which localities the bottom 

 consists of stones and mud, in the latter of soft mud. 



Its small size and the resulting difficulty of distinguishing it from other 

 small nereids, no doubt account for its having been hitherto overlooked. 

 The short cephalic lobe, stout squat palpi, and short tentacles, peris- 

 tomial and parapodial cirri, and peristomium., serve to distinguish it 

 — once its appearance is known — from Nereis pelagica, small examples of 

 which occur in the same localities, but for certainty the parapodia and 

 proboscis must be examined under the microscope. 



Several dozens of specimens in all were collected, and a number of 

 these were examined in detail, as a basis for the following description. 



