Historical 27 



to designate a division in which he placed two tribes, namely, 

 Arenicolides, including the genera Arenicola and Chaetopterus, and 

 Ariciens, comprising the genera Cirratulus, Ophelia, Aricia and Aonis. 

 This usage of the name Arenicoliens was inconvenient, since the 

 six genera referred to the family formed an obviously heterogeneous 

 assemblage ; the conjunction of Arenicola and Chaetopterus was 

 especially indefensible, and was not accepted by subsequent authors. 

 In 1840 Johnston placed the new genus Travisia in the family 

 Arenicolidae, but he soon reached the conclusion that it was desirable 

 to remove it, for in his " Index to the British Annelides," published 

 in 1845, Travisia is found under the family Lumbricidae. 



Grube was led by the general external resemblance between 

 Arenicola and his new genus Dasybranclius to add the latter to the 

 family Telethusa ; Danielssen referred three genera to this family, 

 namely, Arenicola, Scalibregma Eathke and Notomastus Sars. 

 Schinarda carried the inclusive process still further, placing in the 

 family the genera Arenicola, Dasybranchus, Eumenia Orsted and 

 Scalibregma. But Grube and Malmgren successively curtailed the 

 family by removing genera. Grube 1 created a new family 

 Capitellacea for the reception of Dasybranchus, Notomastus and the 

 allied genus Capitella Blainville, and Malmgren founded the family 

 Scalibregmidae for the genera Eumenia and Scalibregma, and thus 

 reduced the family Thelethusae 2 to the single genus Arenicola. 



A second genus was added to the family in 1881 when Langerhans 

 defined his newly discovered Branchiomaldane vincenti as a Telethusan 

 with simple filamentous gills. 



Prof. Mesnil (1897) gave an account of B. vincenti, and of three 

 species of Clymenides^-sulfureus, ccaudatiLs and incertus 3 and pointed 

 out the resemblances of these small Polychaetes to Arenicola on the 

 one hand and to the Maldanidae on the other, liegarding them as 

 connecting links between the families Arenicolidae and Maldanidae, 

 he proposed to indicate the continuous series of forms presented by 

 these two families by combining them into one family, the " Arenicolo- 

 Maldaniens," which, however, he regarded as divisible into two 

 tribes, Arenicoliens and Maldaniens, differentiated by the nature of 

 their segments, " courts et assex nombreux " in Arenicoliens, " longs 

 et peu nombreux " in Maldaniens. Although the relationship 



1 Arch. Naturg., xxviii Jahrg., i (1862), p. 366. 



2 Ofvers. K. Vet. Akad. Forh., 1867 (1868), p. 188. 



3 Since proved to be post-larval stages of Arenicola marina, ecaudata and 

 B. vincenti respectively. 



