BIOLOGICAL STUDY OF TAP WATER. 423" 



of the circumfei'ence, and on the opposite side of the inner cyst there 

 is a similar projection. Stein figures these as occurring about the- 

 same place on both cysts, but in all that I observed they were on 

 opposite sides, and on the outer cyst there was only one. The 

 diameter of the outer cyst in several instances was found to be about , 

 0.0155 mm,, and through the protuberance 0.0217 mm. • and of the 

 inner 0.0124 mm. Figs. 5, 6. 



Dinobryon stipitatum, Stein, was also present once or twice. This, 

 species differs from the one just described in the greater proportionate 

 length of the loricae, which are trumpet-shaped, widest at the mouth, 

 and tapering off into the acuminately pointed posterior end, being 

 about 7 or 8 times as long as their greatest breadth. The zooids 

 very much resemble those of D. sertularia, but are more elongated,, 

 and occupy the anterior half of the lorica, being attached by a 

 thread-like ligament to its lower side wall. A large amylaceous 

 more or less spheroidal body is situated near the posterior part of 

 the endoplasm. The length of the lorica according to Kent is sms"- 



Two or three other species of Flagellata have also been seen,, 

 though rarely. 



One, belonging to the Ghoano-Flagellata, i.e., monads with a collar 

 surrounding the single flagellum, I have referred to Salpingoeca 

 fusiformis, Kent. Kent gives the following characters for this, 

 species : " Lorica sessile, sub-fusiform, or vase-shaped, widest cen- 

 trally, tapering equally towards the two extremities, but expanding 

 again anteriorly into a somewhat prolonged and everted neck ; con- 

 tained animalcule flask-shaped as in S. amphoridium, J. Clark, but 

 of larger size. Length of lorica rims"- Hab., fresh water, solitary." 



Tins form was seen only on one occasion, attached to a frond of 

 Rhizosolenia Eriensis. The lorica was empty and corresponded 

 closely with the above description. In another part of the field 

 however I found what probably was the zooid of this species which 

 had been set free, though it is possible that it might have been 

 Monosiga socialis, Kent, with the description of which it closely 

 agreed. The body was somewhat pyriform, widest posteriorly, with 

 no pedicle ; a single long flagellum surrounded by a collar. Length 

 of the body 0-0062 mm. ( = *tJW), breadth 0-00465 mm. ( = TrdW)- 



On one occasion I got a glimpse of a colony which I think belonged 

 to the familv C odonosigidae of this order. Unfortunately I lost. 



