THE PLANKTON OF EASTERN NOVA SCOTIA WATERS 



13 



SESSIONAL PAPER No. 22a 



in the other case, but had a peculiar superficial sculpture and certain oval depressions 

 (fig. 11) not related to the two ciliary rings whose cilia projected through the shell in 

 separate tufts. Several of the oval areas were counted in front of the prostomial ring. 

 Since the above was written Leschlce's paper* on the pelagic Polychsete larvae of 

 the Bay of Kiel has appeared, in which he records having met on one occasion with a 

 larva similar to the former of these. He also cites previous records of similar occur- 

 r^ces which had escaped me, and from which I am able to state that the Canso larvae 

 obviously belong to the genus Nerine. 



POLYZOA. 



The only larval Polyzoan met with was the Cyphonautes larva of Memhranipora 

 sp. (fig. 12), which was abundant in June and July. 



CRUSTACEA, 



CLADOCERA. 



Two genera were represented abundantly at Canso, viz. : Podon and Evadne. Of the 

 former there were two species appearing at the end of July and of August respectively. 

 I have not been able from my sketches to determine these with certainty, as the- diag- 

 nostic features given by Timm and Plansen (the number of bristles on the exopodites 

 of the various legs) are not recorded there. I suspect the earlier species, however, to 

 be P. polyphemoides Leuckart, on account of its shorter tail lancets and smaller size, 

 and the latter to be P. intermedins Lilljeborg. I find my sketches record that the 

 caudal lancets of the larger species (Plate VI., fig. 1) are tinged with violet and toothed, 

 also that the sculpture of the surface of the shell is different in the two species (figs, 

 lands). 



The two species of Evadne, however, are obviously E. Nordmanni Loven, and E. 

 spinifera P. E. Miiller, the former characterized by the greater elongation of the shell 

 and the latter by the spine which it carries (fig. 3). The former species was abundant 

 at the end of June, the latter common at the end of August. The first winter egg was 

 observed in it on September 6. 



OSTRACODA. 



Only two species of this order were observed, neither belonging to the genus 

 Conchoecia, so it is possible that the few examples observed are fresh water forms 

 swept into the plankton. 



COPEPODA. 



Comparatively few of the numerous species of this interesting order occurring 

 have been definitely diagnosed. The commonest forms are, however, recorded here. 



SUBORDER GYMNOPLEA. 

 C ALAN I DAE, 



Of this family the largest representative, a very abundant one in the earlier 

 part of the summer, was Calanus finmarchicus Gunner. It attracts attention by its 



*Leschke, Beitrage zur .Kenntniss der pelagischen Polychaetenlairven der Kieler Folirde. 

 Wis-senschaftl: Meeresunters: VII.-123. Cunningham and Ramage, Trans. Roy. Soc, Edin., 

 XXXIII. Claparede & Metschnikoff Z. W. Z. XIX, p. 329. Krohn & Schneider Muller's 

 Archiv, 1867, p. 498. 



