526 



THE MICROSCOPE. 



developed. It increases both by budding and by ova, 

 both of which conditions are shown in Plate TV. No. 98. 

 The ova are generally seen enclosed in the transparent 

 case of the parent. In Lophopus and most other fresh- 

 water genera, such as Cristatella, Plumatella, and A Icyo- 

 nella, the neural margin of the lophopore is extended into 

 two triangular arms, giving it the appearance of a deep 

 crescent. 



Trembley gave an interesting account of the family of 

 Alcyonella ; and Mr. J. Newton Tomkins favours us 

 with the following observations on the development of 

 the Alcyonella Stagnorum {fiuviatelld) : — 



" The ova now under examination (^-inch obj. a. eye- 

 piece — 100 lin. diam., Wollaston's condenser), are the 



products of some healthy 

 specimens of A Icyonella 

 stagnorum given me by Mr. 

 Lloyd, and sketched in full 

 activity in September, 1856 

 (fig. 246). Soon after this 

 period their movements de- 

 creased in energy, numerous 

 ova were detached, which 

 floated to the surface of the 

 water of the jar in which 

 the^ were confined, and in 

 the course of a very few 

 weeks no trace remained of 

 the parent animals, except 

 a spongy mass of an almost 

 gelatinous character, which 

 still exists, though devoid of 

 definite form, and appears 

 composed of a mass of 

 broken and disorganised 

 cells. 



" In November, with a view of preserving the water in 

 a normal condition, I introduced a sprig of Anacharis 



rig. 246. — Alcyonella stagnorum (fltivia- 

 tdla), with oviun lying impacted in 

 aaroode : Rotifer vulgaris, and Vurtl- 

 cdla cavijiannlatu, adherent to the 

 iame. (Magnified 100 diameters.) 



u rich nervous plexus resting on the trunk, and connecting the ganglia just 

 jiientioiied, as well as tlie basal ganglia of the individual polypides." For 

 further account, see paper in the Micros. Journ. vol. i. New Scries, p. 330. 



