82 



THE ATLANTIC. 



[chap. II. 



Fig. 21. — Piirocijstis noetilvca, Mukray. Fi'ora 

 the surface iu the Guinea Cuneut. One hun- 

 dred times the natural size. 



general fluid contents of the cell, and burdened with yellow 

 grannies and compound granular masses and minute oil-glob- 

 ules and refractive particles; and near the centre there is always 

 a large, well-defined nucleus of a somewhat denser material and 



of a grayish color, which dyes 

 freely with carmine. This 

 little organism, to which Mr. 

 Murray has given the name 

 of Pyrocystis noctiluca (Fig. 

 21), seems hitherto to have 

 escaped notice, or, if observed, 

 it has probably passed for the 

 encysted condition of Nocti- 

 luca miliaris, which at first 

 sight it greatly resembles. It 

 certainly has nothing what- 

 ever to do with the true Noc- 

 tiluca, which, according to our observations, appears to be con- 

 fined to the neighborhood of land. 



Another species, Pyrocystis fusiformis (Fig. 22), which seems 

 not to be quite so abundant, although it is almost constantly 

 associated with the preceding, is very regularly sj)in die-shaped ; 

 and a third, which may possibly present generic differences, has 

 the form of a truncated cylinder. In this last we have observed 

 the process of endogenous multiplication by the division of the 

 protoplasmic nucleus and the development of two secondary 

 cells within the parent. We are at present inclined, though 

 with some doubt, to relegate these forms to the Diatomacese. 



We took with the towing-net on the surface in the Guinea 

 Current several of the Plagusice, the young flounders described 

 by Professor Steenstrup in a remarkable paper, in which he 

 contended, though somewhat erroneously, that in passing from 

 the young symmetrical to the adult distorted condition, one of 

 the eyes of the Pleuronectidse passed right through the head 



