ON PEDALION iMIKA. 337 



The inner pair of limbs (n) are depressed by the muscle 

 (d), and raised by a pair (c), -which meet in V fashion at the 

 elbow, as it were, of this arm. 



From the point in the dorsal surface where these last four 

 meet, spring four other powerful muscles in two pairs (e), 

 which run right round from the dorsal to the ventral surface, 

 and after following a course nearly transverse to the length 

 of the animal (see figs. 2 and 3), enter the pseudopodium by 

 a turn nearly at right angles, and are attached, the upper to 

 its lower portion (fig. 2, t), and the lower to a spot (fig. 2, 

 u) , around which the pseudopodium can be bent like a hinge, 

 and so thrust out at right angles to the body, or even drawn 

 right up parallel to it, but pointing the wrong way. 



The circular muscles (fig. \, f, g) surround the neck and 

 trochal disc, and serve to enable the creature to regain its 

 right shape Avhen it has contracted its length by means of its 

 longitudinal muscles — viz. two dorsal ones, which are shown 

 in fig. 1, five more side ones in fig. 2, and yet another pair 

 of ventral ones in fig. 3. The pair (fig. 2, s) moves the 

 ciliated chin. All these muscles are coarsely striated. 



Gosse pointed out in vol. ii of the ' Popular Science 

 Review,' 1863, that Polyarthra, as well as other rotifers 

 (Dinocharis, for example), had true condyles in the joints; 

 and that this was one of several weighty reasoRS for giving 

 the whole class " a high place in the natural system,^' near 

 the articulata rather than the annelida ; and surely Pedalion's 

 limbs, worked by such muscles and having such obvious 

 joints, not only bear out Gosse in his assertion, but amply 

 justify Sir J. Lubbock in stating that "some of the Rotatoria, 

 such as the very remarkable Pedalion, seem to lead through 

 the Nauplius form to the Crustacea." 



Within the last week I have captured many females with 

 clusters of male eggs attached to them. Female eggs are 

 never carried more than one or two at a time ; but the male 

 eggs generally hang in bunches of a dozen or a dozen and a 

 half. They are, too, only half the size of the female cggs^ 

 and never show any structure within them except the eyes 

 and cilia. 



I had seen the young female hatched several times, and 

 found it to be (as is always the case in rotifers) an exact re- 

 petition on a small scale of its parent — a funny, fuzzy, little 

 thing, all spikes and bristles. The male, however (figs. 4 

 and 5), is a strange caricature of its mother. When just 

 hatched, it is but l-550th of an inch, or about one fifth of 

 her length, and I do not imagine that it lives long enough to 



VOL. XII. — 'NEW SER. B B 



