MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



of extreme tenuity, that any alteration in the density of the water, as for example 

 when a preservative liquid is added to it, causes speedy disruption. 



An interesting analogy of distribution is presented by Staurostoma and Bolina : 

 S. laciniatum from the north Atlantic coast of America is as nearly related to 

 S. mertensi from the coast of Alaska, as B. alata is to B. septentrionalis from Beh- 

 ring's Straits. All of these species are doubtless descended from circumpolar 

 forms which have streamed down along the different coast lines from the Arctic 

 ocean. 



The neritic plankton is enriched at certain seasons by free-swimming larval 

 forms belonging to the littoral fauna. One of the most bizarre of these was first 

 described by Johannes Miiller as Actinotrocha hranchiata, and was subsequently 

 shown by A. Kowalevsky to be the larva of a worm called Phoronis which lives 

 in sand-tubes. Without entering into details, it may be stated that the chief 

 peculiarity of this form is that in effecting the transformation from the larval 

 to the adult condition, the body becomes, up to a certain point, turned inside out. 

 One example of Actinotrocha, identified with a species previously described from 



Fig. 1. The figure to the left is a magnified'outline sketch from Ufe of Actino- 

 trocha Brownei [de Selys-Longchamps]; that to the right is a similar sketch of Phoronis 

 Brownei immediately after the metamorphosis.*^ Observed at St. Andrew's, New Bruns- 

 wick, August 19th, 1912. 



