16 A 



Canadian Arctic Expedition, 1913-18 



Another collection made on July 19, 1915, from green algae in a creek 

 outlet, Barnard harbour, Northwest Territories, contained twenty-five specimens, 

 of which fourteen were mature. All the specimens of this collection which 

 were sectioned also proved to be Lumbricillus lineatus (Mull.). 



CHARACTERISTICS. Length, about 10-12 mm. Somites, about 50. Diam- 

 eter, in region of clitellum approximately 1 mm. Colour " yellow brown " 

 according to data accompanying the June 12th collection; dark brown in alcohol. 

 Setae sigmoid; approximately uniform in size; 4-6 in ventral bundles; 3-4 in 

 lateral bundles. Clitellum slightly developed; on 12-13; incomplete on ventral 

 surface of body. Anterior and posterior margins of brain slightly concave; 

 lateral margins divergent caudad; length apparently about equal to maximum 

 width. Peptonephridia lacking. Dorsal blood-vessel arising in 14. Nephridia 

 with very small anteseptal part and large postseptal part; efferent duct arising 

 from ventral surface of posterior part of latter. Testes multilobed. Spermi- 

 ducal funnel cylindrical; about three times longer than diameter. Sperm duct 

 confined to 12. Penial bulb of typical lumbricillid form; cells of one kind only 

 in interior. One pair spermathecae in 5; thick-walled; no diverticula; duct 

 and ampulla large, without sharply defined line of division; ental region much 

 narrowed and reflected cephalad before reaching digestive tract; duct shorter 

 than ampulla, surrounded full length by conspicuous glands; ental portion cf 

 each spermatheca uniting independently with dorso-lateral surface of digestive 

 tract; lumen of spermatheca uniting with lumen of latter. Ventral glands in 

 13 and 14; anterior larger than posterior; similar in shape; surrounding ventral 

 nerve cord closely on ventral and lateral surfaces only. 



DISCUSSION AND DESCRIPTION. 



COLOUR. The data accompanying the June 12, 1916, specimen contained 

 the statement " yellow brown worm," which the writer interprets as referring 

 to the colour of the living animal. Since Lumbricillus lineatus has been described 

 from other regions as being brownish red, or red tinged with yellow, it would 

 appear that the Bernard harbour form is typical so far as colour is concerned. 

 l$o data are available on the colour of the living worms in the collection of July 

 19, 1915. 



SPERMATHECAE. In the specimens collected July 19, 1915, the spermathecae 

 were as described above, but in one 'specimen collected June 12, 1916, they 

 lack the connection of the lumen of the ampulla with that of the digestive tract. 

 The ental portion of each spermatheca is adherent to the digestive tract but 

 the connection has not yet been established. That this is a condition of imma- 

 turity is suggested by the fact that there is evidence that such connection is 

 the last of the parts of the spermatheca to be completed. The total absence 

 of spermatozoa in the spermathecae also indicated immaturity. 



PENIAL BULB. It is interesting to note that in the single, partially 

 immature specimen, collected on June 12, 1916, there is a distinct difference 

 in the development of the penial bulb on the two sides of the animal. The 

 right penial bulb is apparently completely developed, and all of the parts are 

 represented in their usual condition in the lumbricillid type. However, on the 

 left side, the bulb is in a very early stage of development, represented only by 

 a small mass of developing tissues in the body-wall, and none of the regions 

 of the fully-developed bulb can be distinguished. Mature specimens in the 

 other collection showed the penial bulbs with the structure as previously described 

 (Welch, 1917a : 128). 



DISTRIBUTION. The writer (1917a : 123-125) has recently pointed out 

 that the enchytraeids formerly regarded as distinct and designated under the 

 names litoreus, subterraneus, verrucosus, lineatus, and agilis, are all one and the 

 same. This synonymy must, of course, be taken into account in considering 



