5 GEORGE V. SESSIONAL PAPER No. 39b A. 1915 



XIII. 



ENTOMOSTRACA OF GEORGIAN BAY. 



By G. 0. Sars, Professor of Zoology, Christiana University, Norway. 



The following is a list of Entomostraca occurring in a series of surface 

 tow-nettings made by Dr. E. M. Walker in the summer of 1907, at the Georgian 

 Bay Biological Station, Go Home, Georgian Bay, Lake Huron. 



CLADOCERA. 



1. Holopedium gibherum, Zaddach. 



Very common in all the samples. 



2. Sida crystallina, Mull. 



Occasionally from the bottom. . 



3. Daphniella brachyura, Lievin. 



Not infrequent in some of the samples. 



4. Daphnia hyalina, var. oxycephala, G. O. Sars. 



This form was recorded by the present author in 1890 as a variety of D. 

 galeata, G. O. Sars. I now, however, regard it as more properly belonging 

 to the species D, hyalina, Leydig, with which also Herrick has identified it. 

 Occasionally in most of the samples. 



5. Hyalodaphnia retrocurva, var. intexta, Forbes. 



This form has erroneously been identified by Herrick with H. kahlbergensis, 

 Schoedler, which is a variety of a quite different species, viz., H. cucullata, G. 

 0. Sars. The present variety exhibits in its general appearance and particu- 

 larly in the shape of the head, a strong resemblance to H. cederstrcBinii, Schoed- 

 ler, which is a variety of H. cristata, G. O. Sars. It differs, however, among 

 other things, in the more obtuse rostrum and in the presence of a well-devel 

 oped natatory seta on the first joint of the lower or inner ramus of the antenna, 

 this seta being wholly absent in H. cederstrcemii. 

 Rather common in all the samples. 



6. Ceriodaphnia scitula, Forbes. 



The most conspicuous character distinguishing this species is the peculiar 

 shape of the fornix, which is produced above the bases of the antennae on each 

 side to a rather large gibboiform prominence. 



Not infrequent in some of the samples. 



7. Bosmina longirostris (Mull.) var. 



This is a very small variety, especially distinguished from the tj^pe by the 

 somewhat longer shell-spines, which, moreover, exhibit each one or two well- 

 marked serrations not found in the usual form. 

 Not infrequent in some of the samples. 



