^2 



conic the wash from the Pass; in other words, when the water 

 was of that deep blue color noticeable well out at sea. At no 

 period during the writer's stay did the waters of the Pass or of 

 St. John's Bayou present any other appearance than muddy. The 

 result then was that out of a total of 18 species, twelve were from 

 the plankton, of which 9 were not represented in the material from 

 either of the other stations, while one was common to all three, 

 one common to the plankton and to St. John's Bayou, and one to 

 the plankton and to the Pass. Of the 6 forms identified from the 

 Bayou only one was not found represented elsewhere, while of 

 the 7 from Calcasieu Pass 2 were exclusive. 



The principal feature of the collections was the overwhelming 

 predominance of a species of Acartia at all the stations and the 

 marked absence of mature forms. The latter is all the more 

 peculiar as at the corresponding period of September, 1902, the 

 writer found at Pass Christian the majority of the species repre- 

 sented in the following list, and the bulk were more or less ma- 

 ture. The lateness of the seasons of 1903 may have been reflected 

 in the development of these minute forms of marine life, and a 

 certain proof of this may be gathered from the fact that the most 

 active reproductive period of fresh-water forms in other sec- 

 tions of the State was towards the end of October. Usually, in 

 the case of these fresh-water forms, the greatest reproductive 

 activity is in the early spring — April and May — and in September 

 and the first half of October. 



The presence of an extra amount of fresh water in Calcasieu 

 Pass and St. John's Bayou, due to protracted high water, might 

 have had some effect on the forms, and in this direction the writer 

 had a kind of demonstration. On September 12 dredgings were 

 made in the Pass between 5 and 6 p. m. The density of the water 

 on this day was 1.0164 (uncorrected for temperature). The 

 forms were exceedingly abundant, although for the most part im- 

 mature. On the following day, under precisely the same condi- 

 tions as to temperature and time of day, but with a density of 

 1.009 (uncorrected), scarcely anything could be got with the 

 dredges, either at the surface, at three feet down or at the 

 bottom. The only forms of Crustacea in any numbers were 

 nauplii of a species of Cirripedia — probably the oyster-shell 

 barnacle — and the zoaea stage of crabs and shrimps. The forms 

 had apparently either sought the Gulf or had succumbed to the 

 changed conditions. 



