NATIVES OF YORKSHIRE. 287 



usually of the lesser Fact, and those being attached to large twisted masses of 

 the same kind, almost render it in appearance a pensile, and wholly a natant, 

 nest, wherein the two kinds of spawn are deposited, while the male fish is 

 generally to be observed swimming around it, chiefly across the aperture, and 

 truly evinces no little parental affection and courage, slowly retiring when 

 molested or alarmed, and presently returning to his station like a trusty centinel. 



As illustrating the causes of disease in marine animals, and, probably also 

 in consequence, that of the occasional unwholesome nature of those animals for 

 food, I would state, that the Common Oyster will sometimes, when it seems 

 sickly, flaccid in substance, and greenish and discoloured in appearance, exhibit 

 proofs of being impregnated with iodine, usually under the form of hydriodate 

 of soda. Can this arise from the Oyster having eaten largely of certain marine 

 plants containing considerable quantities of iodine, and thus producing an 

 unhealthy condition of the fluids, similar to that which takes place in man 

 from the excessive use of mercury or iodine ? 



The Gasterosteus spinachia has been constituted, by Dr. Fleming, a distinct 

 genus, under the term of Spinachia, and with some reason, for it is very like 

 its congeners the Sticklebacks, there being no features of family likeness, except 

 those of voraciousness and pugnacity. In appearance, indeed, it more resem- 

 bles, though very different in structure, a Syngnathus, in those mailed sides and 

 that long and tubular snout. 



Nereis Noctiluca is hardly more than the tenth of an inch long, and of the 

 thickness of a strong bristle ; it occurs plentifully, particularly late in autumn, 

 among the Sea-weeds, especially the lesser Algae, spangling the leaves, when 

 spread open, with countless sparks of a rich and brilliant blue fire. The 

 luminosity of this well-known though minute Molusca, is unquestionably de- 

 pendent upon the will of the animal, which, when disturbed or pursued, can 

 instantaneously extinguish its lamp, and presently rekindle it, and that even 

 if it be removed to a sheet of dry paper, where, however, it speedily dies ; but 

 among the Algce, especially if repeatedly moistened with Sea- water, this marine 

 glow-worm may be kept alive several days. For a very minute description of 

 this singular little creature, I would refer your readers to the monograph of 

 Adler in the third volume of the Amcenitates Academicce. 



Scarborough, May 20, 1837. 



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