52 



The longitudinal body-striae are hardly perceptible. The round 

 nucleus is single and sub-central,- while the contractile vacuole, 

 whicn is quite difficult to distinguish from the many vacuoles 

 nearly always present, is near the posterior extremity. The length 

 varies from 35 to 50 microns. 



This form differs from Blepharostoma glaucoma Schw. ('93) 

 in size (.015 mm) and shape (cylindrical) as well as in the posi- 

 tion of the oral fossa, which in B. glaucoma does not reach the 

 apical extremity, while in B. pigerrima it divides that extremity 

 and makes it sharply pointed. 



Cryptochilium fusiforme Gourret & Roeser ('88) agrees in 

 very many details with my description and their figures (PI. XIII, 

 figs. 2 and 3) would be good if the preoral cilia were less numer- 

 ous (6 from a side view), heavier and inclined downwards. 



Colpoda pigerrima Cohn ('66), notwithstanding the striae de- 

 scribed and figured, I am inclined to believe is the same form. 

 Cohn failed to see the nucleus and describes as the true contractile 

 vacuole, which is usually obscure, the food vacuole which is con- 

 stantly being formed in close proximity to the oral aperture. 



This form has nothing in common with the genus Cryptochi- 

 lium (now Uronema) nor with Colpoda, but naturally belongs to 

 the genus Blepharostoma as erected by Schewiakofif, and where I 

 have placed it. 



GONOSTOMUM PEDICULIFORME Cohn Sp. 



This hypotricbous ciliate one would suppose easy to identify on 

 account of its unique shape. It is divided into two very distinct 

 regions — an anterior neck-like portion and a posterior broader por- 

 tion, together resembling, somewhat, a bass-viol. Cohn ('66) 

 found it in a sea-water aquarium and gave a description of it 

 (Stichochaeta pediculiformis) which Maupas ('83) has amended 

 and found reason for placing it in the genus Gonostomum. 



I had a fairly large number of these forms under my observa- 

 tion, and, in order to study them critically, I isolated several in 

 a watch glass with a few drops of water, killed with i per cent os- 

 mic acid, then treated them as recommended by Schewiakofif ('98) 

 and brought out the appendages very distinctly. The shape of 

 the body agreed exactly with Cohn's figures and description. The 

 size varied somewhat — the largest measuring 140 microns and the 

 smallest 100 microns. 



The greatest width was one-fifth of the length, and while the 

 neck-like portion varied within small limits, its average size was 

 about one-third the body length. The oral aperture, peristome, the 



