Proto::oa and Rot if era at Havana, III. 319 



tinned to appear throushoiit the year, becoming very scarce 

 during cold weather. 



9. D. pyriformis Perty. 



Although this was even less common than the preceding 

 species, its occurrences were quite uniformly distril)uted 

 through the entire year, and it was recorded from all the 

 principal substations. It was also found in Matanzas Lake. 

 It appeared usually in the towings, rarely in shore collections. 

 In February a few were taken in a towing at C, underneath a 

 foot of ice. 



10. D. pyriformis vas Leidy. 



Not common ; taken only in July and August in towings 

 from substations K and L (Flag and Dogfish lakes'). 



11. D. pyriformis compressa Carter. 



In July and August a few appeared in towings from Thomp. 

 son's and Dogfish lakes. 



12. p. urceolata Carter. 



No individuals of this species were found in any of the 

 collections, but in November a quantity of dried mud was 

 collected from the bed of Phelps Lake, which was entirely 

 dry at this time, and several small aquaria were started by 

 placing some of this mud in jars of filtered water. Several 

 examples of 1>. urceolata appeared in these aquaria, as well 

 as other forms which will be mentioned in their proper place. 



13. D. acuminata Ehrbg. 



Like 1>. pjir'iformh, this was scarce, but generally dis- 

 tributed through the year and at the various substations. It 

 also occurred under the ice at C in February, and in Matan- 

 zas Lake. With one exception it was found only in the tow- 

 ings. 



14. D. lobostom.ata Leidy. 



This species was very generally distributed. It was found 

 almost entirely in the towings, associated with D. globidosa. 

 In the fall it became common and even abundant, but was 

 noticeably sparser in winter. This species was among those 

 collected from under the ice at C in February. It is also 

 recorded from Matanzas Lake. 



