PROTOZOANS OF SAINT JEROME'S CREEK. 733 



ments carried oat upon different soils, and for a suificient length of time to enable accidental 

 causes to be eliminated, which could afford a clue to the determination of the relative importance 

 of the action of the several causes above enumerated at the different stages of development of the 

 Oyster. ... I believe the character and abundance of Diatomacea and BMzopoda, and other 

 microscopic animals, in Oyster- grounds,, is of primary importance in connection with Oyster 

 cultivation. The green color of the Colchester and Marennes Oyster shows how much the quality 

 may be affected by such organisms. It is probable that the action or influence of the soil of Oyster- 

 grounds upon the Oyster, at the various stages of its growth, depends mainly upon the nature and 

 comparative abundance of the Diatomacea, Bhizopoda, Infusoria, and other microscopical organisms 

 which inhabit the ground. I have accordingly always noted where the mud appeared to be rich in 

 Diatomacea, Foraminifera, and other microscopic organisms. A thorough a study of a few differently- 

 situated Oyster-grounds, exhibiting well-marked differences in the character of the Oyster from 

 this point of view, by a competent microscopist, acquainted with the classes of plants, and animals 

 just mentioned, would be of great scientific interest and practical importance." 



Protozoans of Saint Jerome's Creek. — The Protozoan fauna of Saint Jerome's Creek 

 presents considerable variety; several species of test-building Gothurnice were noticed, one 

 Yaginicola, three species of Vorticella or bell-animalcules, free-swimming Uuplotes, Nassula; of 

 the latter type an exceedingly elongate form was noticed, with a body almost as slender as a 

 thread-worm. Monads were noted sometimes in profusion, though some of these may have been 

 the spores of algae. Amoeboid forms were very few, and the only one which was frequently 

 noticed was a form so nearly like Actinophrys sol that I would pronounce it the same. 



The Freia producta Wright was most common ; this creature is related to the fresh-water 

 trumpet animalcules, and is one of the most beautiful Protozoans I have ever seen. I reproduce 

 here, with some changes, my description of the Chesapeake form from the "American Naturalist" 

 for November, 1880 : 



" The tubes in which the animalcule resides are formed of a narrow transparent ribbon of 

 horny consistency, wound into a spiral aijd terminating in a trumpet-shaped extremity, from which 

 the odd peristome of the inhabitant protrudes. The basal or attached end is usually bent at an 

 angle to the tube and bears a striking resemblance to the foot end of a stocking resting upon the 

 sole. This portion is not composed, like the tube, of a spiral ribbon, but is simply a thin-walled 

 sac, from the open end of which the ribbon takes its rise, but it is composed of the same kind of 

 material. Many of the tubes show a trumpet-like rim projecting from the sides of the former, a 

 little above the middle, and of the same form as the terminal rim, showing that this, like the form 

 described by Mr. Wright from British waters, may stop building its tube for a time and then 

 recommence. 



" The adult animal, tube and all, when fully extended, will measure one twenty -fifth of an 

 inch iu length. It is of the same color as Stentor cceruleus, or bottle-green, but has the power of 

 elongating and twisting itself as greatly as 8. rceseli. The peristome is quite unlike that of Freia 

 ampulla and bears a strong likeness to the blades of a pair of obstetrical forceps. The blades are 

 deeply grooved, forming a deep ciliated demi-canal with parallel sides, and at the junction of their 

 bases lies the spacious, twisted, and spirally ciliated pharynx, which is bounded dorsally and 

 ventrally by the prominent folds which unite on either side with the long, curved lobes of the 

 peristome. There is a small basal disc as in Stentor, and the ectosarc is traversed as in that genus 

 by parallel granular bands, regarded as muscular fibers by some writers. The usual food-balls 

 and vacuoles are present, and I was enabled to define sharply the endosarc from the ectosarc, 



