Benham. — Oligochaeta from Kermadec Islands. 175 



then it is possible that living worms were also present, provided that these 

 were of small or moderate size. But similar importations have been recorded 

 in manv parts of the world — see Michaelsen (11)* — and there is no doubt 

 that it has occurred in this case. 



In addition to the earthworms, or " megadrilous Oligochaets," Mr. 

 Oliver also collected two species of " microdrilous " genera, and on a previous 

 occasion I received another species from Captain Bollons. These belong 

 to the two families Enchytraeidae and Tnbificidae. The Microdrili are 

 small in size, and the majority are aquatic in habit, and, owing to the fact 

 that very little is known of the Microdrili outside North America and Europe, 

 and of recent years India, it is impossible to use the facts in any discussion 

 as to geographical relations of the islands. For instance, three species of 

 Enchvtraeids, all introduced northern forms, have been recorded from New 

 Zealand by Beddard (5) and myself (1); and three species from the sub- 

 antarctic islands described by myself (2, 4) as new. From Australia, in 

 addition to two introduced species, Michaelsen (12) has described two species 

 from south-west Australia. 



Of the family Tnbificidae, two species were described by me from the 

 lakes of New Zealand (1) and two from the subantarctic islands (4), while 

 one species described by me as new is identified by Michaelsen as being 

 in realitv an introduced European form. From Australia one species of 

 Clitellio has been recorded by Michaelsen (12), while I described two species 

 (a Tnbifex and a Branchiura) from Mount Kosciusko (3). We are thus 

 in need of verv much further work on these smaller worms before they can 

 be employed as evidence for geographical purposes. So far as is known, 

 however, the " home " of the Enchytraeidae is, like that of the Lnmbricidae, 

 the Northern Hemisphere ; and though I describe these as new species 

 I am quite prepared to admit that they may have been introduced into 

 the Kermadecs. 



Since it is known that a single cocoon formed by such a worm as an 

 Enchvtraeid may contain several eggs or embryos, the arrival of such a 

 cocoon, by whatever means it may be transported, in an island such as 

 Sundav Island is sufficient to start a new colony of that species. For 

 instance, Michaelsen (9, p. 11) records for Lumbricilliis maximus that in 

 one cocoon he opened there were as many as 33 eggs ; in others, from 20 to 

 30 embryos. 



Fam. Enchytraeidae. 

 Fredericia bollonsi sp. n. 



Three well-preserved specimens were received from Captain Bollons in 

 1904, without any definite information as to the conditions under which 

 they were collected. One of these was stained and 

 mounted as an entire object, and later cut into sagittal 

 sections ; another was similarly studied, and then cut 

 into a series of transverse sections. p IG _ i p bollonsi. 



As the specimens are all more or less curved or A chaeta. 



curled, it is only possible to give approximate measure- 

 ments ; they measure from about 12 mm. to 16 mm., and in a shorter one 

 I counted 56 segments. 



The chaetae are two in each of the dorsal and ventral bundles, and this 

 number is retained throughout the worm ; only here and there in a verv 



* These numbers refer to the list of works given in the bibliography at the end of 

 the paper. 



