37 



is no doubt however about tlieir existence in some other 

 parts of the bay. SlipjDer limpets Were frequently ob- 

 served adherent to the outside of oyster shells, the only 

 species though, which I observed, was the one called 

 Crepidula glauca. The unripe eggs of this animal have 

 a very remarkable structure, the nucleus containing a 

 large and very refringent nucleolus which looks like 

 two spheres partially fused together, from this body to 

 the walls of the nucleus granular protoplasmic lines ex- 

 tend in a very irregular radiating manner. These gran- 

 ular lines sway and twist about while the fresh egg is 

 viewed under the microscox)e, like a spider' s web, which 

 may be supposed to have been endowed with life and the 

 power of moving any part of itself. E. Van Beneden 

 and O. Hertwig figure very similar immature ova occur- 

 ring in other animals. 



A number of sponges were observed ; all of them sili- 

 ceous; some of them incrusting stones and oyster shells, 

 others were branching or massive and usually of a yel- 

 low, yellowish or dirty white color, except some leather 

 sponges (Geodia?) which were purplish and anchored in 

 a most remarkable manner to the bottom. The red- 

 sponge, Microciona proliferiim, is very common, but the 

 species which most concerns the oyster culturist is the 

 boring sponge, the substance of which is deep orange in 

 color. The boring sponges, Clionoe^ are very destructive, 

 but whether they really destroy many living oysters in 

 this country is probably not ascertained. That they can 

 effect the destruction of the oyster there can be no doubt 

 from the following which I published over a year and a 

 half ago elsewhere." "In a specimen of the ccmimon 

 Ostrea mrginiana^ recently handed me for examina- 

 tion by my friend Mr. John Ford, tlie sul)stance of the 

 shell was thoroughly cavernated so as to render it ex- 

 tremely brittle and readily crushed; in fact tlie inner 

 table of the shell left standing showed a great number 



u 



C( 



*0n tht Destructive Nature oTthe P>oring Sponge, etc. Am. Naturalist, XI 11. 1879, p. 2S1. 



