OF THE FLOSCULAEIJKA. 



673 



and other aquatic plants. Length 1-12" 5 

 case 1-24" ; egg 1-150". 



The pellets forming the case were 

 thought by Ehrenberg and others to be 

 deposited from the cloacal orifice ; but, 

 from the careful researches of Mr. Gosse, 

 this appears to be an error (Trans. 

 Microsc. Soc. 1851, vol. iii. part. ii. p. Q2). 

 That observer points out the existence 

 of a special rotating organ of a cup-like 

 figui-e (xxxvi. 1 c) (the disc seen above), 

 seated immediately above the projecting 

 tube. This organ "^he saw fill and empty 

 itself " many times in succession, until 

 a goodly array of dark pellets were laid " 

 down irregularly, the animal efifecting 

 their distribution by bending its head 

 downward, so as to bring this cup and 

 the margin of its sheath into apposition. 

 " After a certain mmiber were deposited 

 in one part, the animal would suddenly 

 tm-n itself round in its case and deposit 

 some in another part. It took from two 

 and a half to three and a half minutes to 

 make and deposit a peUet." Coloured 

 particles in the water " are hurled round 

 the margin of the ciliated disc, until they 

 pass ofi" in front through the great sinus 

 between the large petals ; " and the atoms, 

 if few, "glide along the facial sui'face, 

 following the irregularities of the out- 

 line with great precision, dash roimd the 

 projecting chin, and lodge themselves 

 one after another in the little cup-like 

 receptacle beneath," in which again they 

 are whirled round with great rapidity, 

 and prepared into pellets for the building 

 up of the case of the animal. 



The internal organization of this ani- 

 mal has been investigated by Professor 

 Williamson. Like Lacimdaria, the tro- 

 chal disc is double at its margin, with 

 two rows of rotary cilia, the currents 

 created by which are directed to the 

 mouth and pass oft* by the ciliated "chin" 

 — a small additional lobe above the cili- 

 ated cup of Mr. Gosse. On each side of 

 the trochal head are two hollow pro- 

 cesses or " calcars " — the respiratory 

 tubes of Ehrenberg, but which are pro- 

 ba,bly tactile (xxxvii. 17 d). These ter- 

 minate externally in a deltoid body (13), 

 from which projects a pencil of straight 

 setae.^ Along the interior of this tube is 

 a delicate muscular band, by which the 

 setigerous extremity can be drawn back- 

 wards into the tube (14), and the setae 

 thus be removed out of danger. The 

 alimentary canal much resembles that of 

 Lacimdaria. There is a narrow oeso- 

 phagus conducting do"waiwards to the 

 pharyngeal bulb (figs. 17 e and 23), in 



which are implanted the peculiar jaws : 

 these are complex (f. 26), consisting of 

 equilateral sets of numerous transverse 

 bars, those of each set connected at their 

 peripheral extremities by an arcuate lon- 

 gitudinal one, and at their inner extre- 

 mities by a double broad longitudinal 

 one prolonged upwards into a long nar- 

 row handle or process which meets its 

 fellow of the opposite side at a kind of 

 hinge-like joint. These jaws work upon 

 one another with a crushing motion by 

 means of the above joint, — the upper part 

 of the alimentary canal, and consequently 

 the food swallowed, passing between 

 them. Below the pharyngeal bulb is an 

 oblong stomach, with cellular parietes 

 and lined with cilia. A constriction 

 separates this from a lower and more 

 spherical portion (17 g), also cellular 

 and lined with still longer cilia. This 

 opens into a long cloaca (17 U), which 

 turns suddenly upwards to its terminal 

 outlet (17 i). The interior of the body 

 contains numerous free muscular bands. 

 These are especially distinct in the pe- 

 duncle, along the entire length of which 

 several of them run, which shorten 

 the body in its axial line. Each fasci- 

 culus consists of transversely striped or 

 voluntary muscular fibre, and is enclosed 

 in a sarcolemna or membranous sheath 

 (18). Difiiised through the body of the 

 animal, but specially distinct at the up- 

 per part of the peduncle, are numerous 

 small masses of \dscid gTanular proto- 

 plasmic substance, Avhich send slender 

 prolongations to each other and to the 

 surrounding parts, reminding the ob- 

 server of the pseudopodia of the Rhi- 

 zopods and the internal threads of 

 Noctiluca. 



The water-vascular system consists of 

 two canals arising from a small pyrifomi 

 contractile vesicle below the stomach, 

 and apparently with the cloaca. One 

 ascends on each side of the alimentary 

 canal towards the head, where they 

 branch. Vibratile tags are connected 

 with them. 



Professor Williamson describes the 

 ovary as " a hollow sac (xxx-^t:i. 23 y), 

 consisting of a very thin peUucid mem- 

 brane. It is filled with a viscid granular 

 protoplasm of a light grey colour, in 

 which ai-e distributed from twenty to 

 thirtv nuclei, each having a diameter of 

 from' 1-1200" to 1-1600". Each nucleus 

 contains a large nucleolus, varying in 

 diameter from 1-1600" to 1-3500". In 

 its normal state the gi'anular protoplasm 

 is of a unifoi*m grev colour, flowing 

 2x 



