ANIMAL DISTRIBUTION FOLLOWING A HARD WINTER. IO3 



north. The Biological Survey says that it first appeared in New 

 Haven in 1892 and at Woods Hole in 1898. Professor Verrill 

 believed that this Sagartia was introduced near New Haven on 

 oysters from the south. Professor Parker states that it is a 

 southern ranging species. 



One more particular instance of a marked decrease in abun- 

 dance was that of the red sponge, Microcione prolifera. In the 

 early part of the season this sponge was almost absent from the 

 wharf piles. Later they became more abundant. 



In a number of instances the cold weather killed off the animals 

 living in shallow water and left only those in deeper water. This 

 tendenc)' has already been mentioned in the case of Arbacia. 

 It was also marked with the encrusting bryozoa as, Schizoporella 

 imicornis. 



In Table III. the data concerning Platynereis is listed as being 

 insufficient to furnish a fair comparison. As a matter of fact 

 none were taken this year but usually the number taken in the 

 class collecting has been small and it is possible that we over- 

 looked them this year. However, Dr. E. E. Just, who has been 

 collecting swarming annelids for some years, reported that up 

 to August i he had taken no Platynereis in his night collections 

 although usually they are abundant by that time. Autolytus 

 cornutus (A. Agassiz) was also lacking in his collections at that 

 date although normally present. Unlike the other species this 

 annelid is northerly ranging. It is found from New Jersey to 

 the Bay of Fundy. Dr. Just also reported that the cold spring 

 had affected the periodicity 1 of the early runs of Nereis limbata 

 in a way wholly comparable with other late springs. 



It is to be expected that the negative effect of a cold winter 

 would be more noticeable than its positive effect. However, 

 two northerly ranging species were present in decidedly increased 

 numbers in the collecting. The more noticeable of these was 

 the sponge, Leucosolenia botryoides (Bow.). Pratt gives its range 

 as from Martha's Vineyard to the Gulf of St. Lawrence. Usually 

 we have taken it to some extent in the class collecting on wharf 

 p'lings, but this year it was very abundant there and was found 



1 Lillie, F. R., and Just, E. E., 1913, "Breeding Habits of the Heteronereis. 

 Form of Nereis limbata at Woods Hole, Mass.," BIOL. BULL., 24, pp. 147-169. 



