General Index 



169 



Septa, of Arenicola, 61, 62, 75 ; of B. 

 vincenti, 152. 



Septal pouches, of Arenicola, 62 ; ab- 

 sent in A. pusilla and assimilis, 

 62, and in B. vincenti, 152. 



Serpuleae (Savigny), 13, 19. 



Setipodes (Blainville), 14, 15. 



Size, of A. marina, 97, loveni, 105, 

 cristata, 108, 109, glacialis, 114, 

 pnsilla, 121, assimilis, 130, ecau- 

 data, 135, 136, branchialis, 145, 

 .B. vincenti, 148. 



Spermatozoa of Arenicola, 72. 



Statocysts, of Arenicola, 67-70 ; varia- 

 tion in size of, 70 ; external aper- 

 tures of in marina, assimilis, gla- 

 cialis, 39 ; of post-larval marina, 

 78, cristata, 79, assimilis var. 

 affinis, 80, ecaudata, 81, bran- 

 chialis, 82. 



Statocysts, absent in ^4. pusilla, 67, 

 and in B. vincenti, 153. 



Statoliths of Arenicola, 67-70 ; differ- 

 ence in nature of, 69. See also 

 statocysts. 



Sternaspidae, contrasted with Areni- 

 colidae, 160. 



Sub-rostral process of crotchet, 48, 50. 



Swimming, of A. marina, 97; of A. 

 ecaudata, 135. 



Tail, of caudate species of Arenicola, 



37, 38; of A. cristata, 109, 110. 

 Tail segments, site of production of, 38. 



Telethusa, Telethusae, Telethuses 

 (Savigny), = Arenicolidae, 13-16, 

 24, 25, 26, 27, 159. 



Tube, presence of as character of group 

 of worms, 11 ; enveloping post- 

 larval A. marina, 77, 78, cristata, 

 79, assimilis var. affinis, 80. 



Tubicoles (Cuvier), 12, 16, 23. 



Type specimens, remarks on, of A. 

 loveni, 105, glacialis, 113, 114, 

 pusilla, 117-119. 



Variations, in nature of statoliths, 67- 

 69 ; in size of statocysts, 70 ; in 

 number of gills, of A. cristata, 



109, pusilla, 122, assimilis, 130, 

 ecaudata, 136, branchialis, 145 ; 

 in number of nephridia of cristata, 



110, assimilis var. affinis, 131, 

 ecaudata, 136 ; in number of 

 oesophageal glands of pusilla, 122, 

 assimilis, 131 ; in number of seg- 

 ments of ecaudata, 136, branchi- 

 alis, 145 ; in caudal processes of 

 cristata, 109, 110. 



Ventral groove of Arenicola, 38. 

 Ventral nerve-cord of Arenicola, 66. 

 Vermes, 2-9 ; distinguished from " In- 



secta," 9. 

 vincenti (Branchiomaldane), 147-159. 



Willis, 4. 

 Willughby, 5, 91. 

 Wotton, 2. 



