82 SEVENTEENTH REPORT. 



some doubt. Tn addition to the ordiiiavy birotnlate spicules of the 

 gemmules. there is a variable number of bicapitate spicules with 

 heavier shafts, which tend to lie near the inner ends of the birotu- 

 lates and to approximate a tangential relation to the gemmule wall. 

 It is intended to give them more extended treatment in a later 

 paper. 



Eeteromycnia repens (Potts). Common in beach pools and 

 Smith's Bog. Also collected in Burt Lake. 



Heteromyfjcnia rt/deri Potts. Common in Bessey Creek and 

 Smith's Bog. 



Heteromijenia argijrosperma (Potts). Common in Smith's Bog. 



Carterius tuhisperma (Mills). Abundant in Bessey Creek and 

 beach pools. 



Tuhella pemisylvanica Potts. One specimen in Smith's Bog. 



Some species have a much more general distribution than others 

 jind it was noticed that in some of the situations studied, there was 

 i\ marked difference in the relative numbers of certain species in 

 different years. This was especially noticeable in Bessey Creek 

 where the most abundant species in 1011-1012 was the fomi listed as 

 Ephydatia fturiatilis? and Hetcromyciiin ryder'i was not collected. 

 Tn 1013, the last named species was decidedly more abundant than 

 the former. 



BRYOZOA. 



PhimatelUi punctata Hancock. This is by far the most abundant 

 species and is widely distributed in the region. It is common on 

 the submerged surfaces of various water plants and many non- 

 living objects. 



Fredcricella sultana Blumenbach. Oiccurs sparingly near Grape- 

 vine Point in Douglas Lake and also in Burt Lake. 



Cristatella nincedo Cuvier. Numerous colonies were found in 

 Maple River near Douglas Lake in July, 1013 and 1011. Ciliated 

 embryos were liberated in considerable numbers during the next few 

 days after collection. Statoblasts were not ])resent and hence it 

 was not determined whether the typical form or a variety was 

 represented. Statoblasts from the typical form were found in 

 Munroe Lake, a few miles distant. 



OLIGOCHAIOTA. 



The earthw<»rm fauna of the region corresponds in general with 

 Avhat one would be led to expect from a study of the few pa])ers 

 already published, which deal with the earthworm fauna of the 

 northern tier of states and of Canada. With the exception of the 



