OF THE BEACHIONJ£A. 



711 



burst with a bound from the egg in 

 which the motion was perceived, and 

 afiLxed itself by its tail to the lunette. 

 At first it hai the appearance of an 

 oblong ball ; by degrees the anterior part 

 spread, and fhe wheel processes were 

 developed. Soon after, the posterior shell- 

 processes were visible in a semilunar 

 shape, with the points nearly touching 

 each other, which gradually expanded. 

 The shell of the egg remained attached 

 to the parent in the same position, quite 

 transparent, with a longitudinal split 

 through the whole length." (Brightwell, 

 op. cit.) 



B. polyacanthus (M.). — ^Lorica smooth, 

 ha^-ing anteriorly fom' long dorsal teeth 

 or spines, six short ones at the margin 

 of the chin (ventral), and posteriorly 

 five dorsal spines, the two external or 

 lateral ones very long. xxxv. 499-501 

 represent dorsal, side, and imder ^-iews 

 of this animal, — the first having the 

 wheels extended, and the side view 

 showing the siphon or so-called respi- 

 ratory tube and an ovimi attached. 

 Length, without spines, 1-110". xxxvin. 

 14, 15 represent diagTams of the head. 



B. miJitaris. — Lorica ^^dth surface 

 divided into tw^elve regular pentagonal 

 facettes, according to Cohn; its anterior 

 border with several spinous processes j 

 and posteriorly is a deep median ex- 

 cavation with a curved horn on each 

 side. The spines, 10 in number (not 12 

 as afiirmed by Ehrenberg), viz. 2 lateral, 

 4 abdominal, and 4 dorsal, the latter the 

 largest ; head larger than that of B. ur- 

 ceolaris, expanded in a funnel-shaped 

 manner, surroimded by a circlet of cilia ; 

 its eversion is checked by the stifi' spines 

 of the lorica. Foot smaller and shorter 

 than in B. urceolaris. OEsophageal bulb 

 quadrangidar. On each spine forming 

 the outer posterior angle of the lorica is 

 a circular pit with well-defined margin ; 

 from this proceeds a bimch of short 

 bristles. Muscles of foot and head striped 

 transversely. Contractile sac very large, 

 occupying two-thirds of the abdominal 

 cavity on the right side of the animal ; 

 it consists of two chambers, the ovate 

 posterior one being the larger, their con- 

 tractions being alternate ; the posterior 

 one opens into the cloaca by a short 

 duct. On mingling colom^ed matter with 



the water, Colin observed that on each 

 systole or contraction a stream escaped 

 from the sac, through the cloacal open- 

 ing, and that on the diastole this move- 

 ment was reversed, indicating a respi- 

 ratory action, (xxxix. 21, 22 represent 

 the abdominal and dorsal surfaces of the 

 female.) The ova are of three sorts : — 

 1. Winter ova, 1-21'" long, 1-33"' wade, 

 elliptic, with thick, leathery, opaque 

 walls, the yelk not occuppng the poles 

 (xxxix. 23) j 2. Ordinary or summer ova, 

 of similar dimensions, but with thin 

 transparent walls ; 3. Male ova, only 

 1-34"' long and 1-42'" broad (xxxix. 

 24). Shell thin. Yelk subdividing in 

 the usual way, and developing an em- 

 bryo provided with a red eye, and two 

 dark specks, but no maxiUary organs. 

 Cohn saw only one specimen freed from 

 the egg, and that imperfectly. It ap- 

 peared similar to the male of B. ur- 

 ceolaris. 



B. Oon (Gosse). — Lorica ovate, the 

 back swelling with a unifonn ciu've, by 

 which it is distinguished from B. Paki, 

 which is truncate or slightly clavate 

 posteriorly ; anterior spines fom-, straight, 

 wide at the base, and pointed ; the occi- 

 pital pair taller than the lateral. Lorica 

 1-125". 



B. Dorcas. — Lorica ovate or sub-coni- 

 cal ; occipital edge with four long slender 

 spines, the middle pair cm^v-ing forwards, 

 and bent first from, and then towards 

 each other, like the horns of an antelope ; 

 mental edge undulated, with a notch in 

 the centre. Lorica 1-60". (xl. 11 re- 

 presents a newly-bom female, and fig. 12 

 a newly-bom male.) 



B. angidaris. — Lorica in the female 

 hexagonal-oval in the dorsal aspect ; occi- 

 pital edge with two small teeth, divided 

 by a roimded notch (in some specimens 

 there are obsolete traces of a lateral 

 pair) ; mental edge slightly undulated, 

 sometimes wdth two low points, divided 

 by a notch like the occiput, but still 

 more faintly; posterior extremity with 

 tw^o short, blunt, weU-marked processes. 

 The general smface is roughened "vvdth 

 angular ridges, and is sometimes sub- 

 opaque and browTi. Lorica 1-200". This 

 cm-ious species has relations with Noteus 

 and with Pterodina. (xi/. 19 represents 

 a male of this species. ) 



Genus PTEEODIN'A. — The winged Rotatoria include such Brachionaea as 

 have two frontal eyes and a simple styliform foot projecting from the middle 

 of the body. AU the species have a smooth, flat, and soft lorica, like a tor- 

 toise-shell, with curv'ed margins ; as also a more or less double rotaiy appa- 



