112 The Ottawa Naturalist. [July 



Cristatella Id^, Leidy, 



Colonies of this genus are oval in shape, flat on the under 

 side and convex on the upper side, with the polypides in rows 

 all around, except along the centre of adult specimens, where 

 statoblasts are to be seen. Individuals of this genus after 

 emerging from the statoblast, form a small lump or mass of jelly 

 semi-transparent in colour, and usually pear-shaped. In the 

 adult form it is not unlike a hairy caterpillar, owing to the pres- 

 ence of numerous buds which proceed from the ectoderon. By 

 budding, the colony grows rapidly in length (but not in breadth) 

 till it reaches a length of two or three inches, when it measures 

 a quarter of an • inch in breadth. A specimen found in the 

 Rideau canal on a sunken barge measured four inches in length_ 



This form differs from all others in two particulars, {a) in 

 having powers of locomotion ; {b) in preferring sunlight during 

 life. Cristatella moves very slowly, covering a length of about 

 one inch per day. By carefully marking off certain spaces on 

 the object on which it rests, the distance travelled can easily be 

 ascertained. The polypide of this species has many points of 

 resemblance to Plumatella. The tentacles are about eighty in 

 number. The statoblasts of Cristatella consist of rounded flat- 

 tened discs, which have the margin covered with two rows of 

 doubly barbed hooks resembling anchors. 



Locality and habitat. Occurs on stones at little rapids on 

 Rideau River above Billings' Bridge ; also on stones at Hurd- 

 man's Bridge, Rideau River ; in Patterson's Creek, Ottawa, be- 

 tween the Bank street and Elgin street bridges on blades of 

 submerged grass ; also on beam of a sunken barge on Rideau 

 canal at Bronson's wharf October 1898. 



Pectinatella magnifica Leidy. 



" The reproductive and vital energies of the group reach 

 their climax in the voluptuous beauty and endless multiplication 

 of the coenoecia in Pectinatella."* " The colonies of this class 



^Hyatt '• Observations on Polyzoa " p. 12. 



I 



