~ THE WINTER PLANKTON 7 
SESSIONAL PAPER No. 38a 
clausit Giesbr. A glance at the table will show that this species occurred in nearly 
every gathering throughout the season, and that up to the early part of April it was 
almost always in abundance. Its reduction in numbers after that date in association 
with the appearance: of Thalassiosira has already been commented upon. Another 
Pontellid observed was the interesting J'ortanus discaudatus (Thompson and Scott) 
Giesbr. It was taken in several gatherings made during the autumn and early 
winter, but after December it was not again noted until the end of May. In con- 
nection with this form, it may be noted that Giesbrecht and Schmeil! question the 
correctness of Thompson and Scott’s original description of the endopodite of the 
first pair of legs being three-jointed. There is no doubt, however, that the original 
description is quite correct, discaudatus differing from other members of the genus 
in this respect. 
Of the Cyclopide, Ozthona similis Claus was the only form cbserved, and that 
in small numbers in but three gatherings. 
The Harpacticide have hitherto received but scant consideration in plankton 
Nests, partly, no doubt, to difficulties inherent in their identification. The excellent 
monograph of the family by Sars’ does away with some of these difficulties and, 
with its aid, it has been possible to determine the occurrence in the collections of a 
number of forms hitherto unrecorded from Canadian waters. The most frequent 
species was undoubtedly Harracticus uniremis Kroyer, which is readily distin- 
guishable from H. chelifer (Miller), among other things by the first antenne being 
nine-jointed instead of eight-jointed, and by the inner expansion of the proximal 
joint of the fifth pair of legs bearing four marginal sete instead of three. H. chelifer 
has been recorded by Wright* as occurring at Canso and also by Williams* from 
Rhode Island waters, where H. wniremis was also found. It iis possible H. 
chelifer also occurs at St. Andrews; indeed, certain forms were identified as belong- 
ing to that species when the study of the collection was begun, but the identification 
was made with insufficient literature and before access was obtained to Sars’ Mono- 
graph, and opportunity has not occurred for confirming the identification. It seems 
probable that it was erroneous in the majority of cases. 
A second (or third) species of Harpacticus was one which closely resembled 
that described by Sars as H. gracilis Claus, differing from H. uniremis by the greater 
relative shortness of the terminal portion of the first antenne and by the two t-rmin:] 
joints of the endopodite of the first pair of legs being confluent. 
Two species of Zaus were observed, distinguishable by the form of the fifth pair 
of legs. One was evidently Z. abbreviatus Sars, hitherto recorded only from the 
coast of Norway and from the islands north of Grinnell Land; the other apparently 
Z. spinatus Goodsir, previously known from the eastern coast of the Atlantie and 
from the Arctic ocean. IJdya furcata (Baird) was also occasionally found. It is a 
species of wide distribution, and has been rezorded from Rhode Island by Williams. 
A few examples of Parathalestris Jacksoni (Scott) Sars were also observed, a 
form not hitherto recorded from the Western Atlantic, a statement also true for 
Halithalestris Croni (Kroyer) a single example of which was taken, unmistakeable 
from its exceedingly long and divergent fureal rami.° 
Cirrhipedia. 
A few Cirrhipede larve were observed in one of the October collections and 
again on February 20, February 26, and March 2. On March 6, they were present 
1W. Giesbrecht and O. Schmeil. Copepoda I. Gymnoplea. Das Tierreich, Lief. 6, 1898. 
2G. O. Sars. An Account of the Crustacea of Norway. Vol. V. Bergen, 1911. 
3R. R. Wright. The Plankton of Eastern Nova Scotia Waters. Contr. to Canadian Biol., 
1902-5. Ottawa, 1907. 
4L. W. Williams. Notes on the Marine Copepoda of Rhode Island. Amer Nat. xl, 1906. 
5In the table all the Harpacticide have been grouped together under asingle heading, since 
with the exception of H. uwniremis they were of very occasional occurrence and then only in small 
numbers. 
