Benham. — On Lumbricillus macquariensis. 189 



Art. XXIV. — On Lumbricillus macquariensis Benkam. 

 By W. B. Bbnham, D.Sc, F.E.S. 



[Read before the Otago Institute, Itf December, 1914.] 



In 1904 I described a species of Enchytraeid from the Macquarie Islands 

 under the name of Lumbricillus macquariensis (1, p. 295). Later, in 1909, 

 I gave an account of a worm from the Campbell and Auckland Islands, 

 to which I gave the name L. intermedins (2, p. 261). Recently I have 

 received from Mr. Harold Hamilton additional specimens from the Mac- 

 quaries, where he was collecting during his stay there as a member of the 

 Mawson Antarctic Expedition ; and I have been entrusted with the large 

 series of Annelids, both marine and terrestrial, which was collected by that 

 expedition. While studying the Enchytraeids I was led to re-examine 

 my preparations of the specimens received at the earlier dates, and have 

 arrived at the conclusion that the species " L. intermedins " is identical with 

 L. macquariensis. 



A comparison of the two accounts shows that the points of difference 

 affect the following organs : (a) The nature of the spermathecal opening 

 into the oesophagus ; (b) the number of chaetae in each bundle ; (c) the 

 segment in which the dorsal vessel becomes free from the intestinal blood 

 sinus ; (d) the number of the subneural copulatory glands ; (e) the size 

 and proportions of the spermiducal funnel, j 



A. The re-examination of the type of L. macquariensis, and of sections 

 made of other specimens received at that time, shows that I made an error 

 in affirming and figuring the existence of " a narrow duct " putting the. 

 spermatheca into communication with the oesophagus. And to this error 

 I added some confusion in a note at the end of my account of 

 " L. intermedins " by stating (p. 261), " It is quite distinct from L. mac- 

 quariensis, which belongs to another group of the genus in which the 

 spermathecal duct is strongly marked off from the ampulla." The 

 latter statement is clearly a lapsus calami, for what was intended is 

 evidently a contrast with the " narrow communicating-duct,'"' and not with 

 the external opening. 



But it is difficult now to understand how I came to make the original 

 statement as to the existence of the " narrow communicating-duct." The 

 series of transverse sections show quite distinctly that there is no such 

 " duct " — -the ampulla communicates with the oesophagus by a small pore 

 due to the sudden contraction of the ampulla, as I have described and 

 figured for " L. intermedins " (pi. x, fig. 8). 



In order to convince myself further I opened a specimen from the same 

 lot, and it is certain that no such " duct " exists. The mounted specimen 

 which served as the type, when studied without the knowledge derived 

 from the other studies, does suggest a short duct, as the spermatheca is 

 bent at a point close to its entrance into the oesophagus ; but with the 

 other evidence before me I recognize that the statement was due to faulty 

 observation. (It is worth noting that Michaelsen made a similar error in 

 his first account of L. maximus.) 



