A New Rotifer, Lacinularia striolata. 29 



17) were found, the latter possessing a hard shell with banded 

 markings. No observations of the method of impregnation were 

 made, but males were seen repeatedly plunging into the colony 

 between the females and disappearing from view. Spermatozoa 

 occur in the sperm sac, coiled up in a flask-shaped capsule (Fig. 

 18), which is ciliated on one side, and on being forced into the 

 water by compression rapidly disintegrates, and the spermatozoon 

 (Fig. 19) is set free. The length of a spermatozoon is about 

 •045 mm. 



Structure of Peduncle and Matrix of Colony. — A transverse 

 section across the peduncle and along the equator of the colony, 

 shows the peduncle composed of a dense brownish mass, with 

 irregularly shaped cavities in it (Fig. 20). Radiating from it 

 and given ofi" from projecting angles are the walls of tubes (Fig. 

 20, w.t., and Fig. 20, a.) which contain the individual rotifer. 

 For a short distance these tubes are thin and rigid, and then 

 gradually pass into a soft gelatinous substance. The matrix may 

 be regarded as a ball of mucous perforated with radiating conical 

 pits, hardened towards the centre. Each pit contains a rotifer 

 with its foot attached to the bottom (Fig. 20, ter.), which is a 

 short distance from the peduncle, and this forms a septum 

 perforated in the middle to permit the passage of mucous or 

 cement through it. Fig. 20 shows this where ter. is the bottom 

 of the pit and the point where the foot terminates, and miic. the 

 mucous thread exuding from it and connecting the animals with 

 the peduncle. Evidently the peduncle is the product of the 

 combined exudations of the whole colony and grows in length 

 as the individuals mature, and this is corroborated by the fact 

 that the younger colonies possess a shorter peduncle. The cavities 

 are due to stresses set up by the rates of deposition differing in 

 certain portions of the colony, the cement being plastic near to 

 each animal. As the mucous or foot glands (Fig. 3, m.g.) extend 

 over four-fifths of the entire length of the animal, the formation 

 of the softer and more bulky part of the matrix towards the 

 periphery may be due to secretion from the surface, as is the 

 case in the Floscules, and even in some free swimming forms as 

 the genus Copeus. There are reasons for regarding the whole 

 mass as a joint product and not the adherent tubes of the 

 individuals, as will be seen later. 



