OF THE FLOSCULARI/EA. (509 



stomach have a thick layer of large cells filled with j'ellow granules or fat- 

 corpuscles. Intestine transparent and ciliated internally. A contractile sac 

 connected with the cloaca, from which spring two broad water-vascular 

 canals, which are lost anteriorly in front of a fatty mass surrounding the 

 proventriculus. Ovarium developing but few ova at a time ; these, w^hen 

 discharged from the ovary, are still seen to be enclosed in a membranous 

 o^-iduct, extending from the ovary to the cloaca. No male organ hitherto 

 discovered. 



Immediately above the proventriculus is a large collection of hyaline 

 vesicles, which e\ddently open externally by a short duct. A dark granular 

 vesicle appears at the posterior end of the body of the embryo, as in Tubico- 

 laria and Melicerta, — supposed by some authors, but without sufficient reason, 

 to be a uiinary concretion. Two eye-specks at the opposite extremity of the 

 embryo. Two vibratile spaces also a23pear simultaneously, the one in front 

 of the other. The vibratile action is active within the anterior one, whilst 

 witliin the other a few long cilia undulate slowly. 



"WTien the embryo is iii'st distinguishable, and separable from the egg, it 

 has a vermiform figure, and is about 124 millimetres in length. The head, 

 supporting the eyes, is separated from the body by a constriction ; its margin 

 is furnished with numerous cilia, the whole being retractile. Within the 

 body and behind the head are several longitudinal stripes of a doubtful 

 natiu'e ; and still more posteriorly is a clear space with some long ciHa in 

 action, which may represent the alimentary cavity ; the maxillary jaws are 

 perceptible, and the posterior extremity furnished with some cilia. On one 

 occasion Leydig met ^\ith another form of embryo, which retained the vermi- 

 form aspect in its body and foot, but with the former elongated, and termi- 

 nated by four arms. Two eye-specks present, and a proboscis in front, with 

 two extended tubular processes terminated by cilia. Extremity of the foot 

 devoid of cilia. The maxillae were fully developed ; and, near the sac with 

 the dark granular concretions, ciliary vibration was discernible. Leydig 

 thinks that the dark granules of the sac escape into the cloaca, and regards 

 them as ui'inary concretions accumulated in the extremity of the intestine. 

 Cohn rejects the idea that they so escape ; and we believe him to be correct 

 on this point. The granules are affected by potash, but not by acetic acid. 



Stephanoceros Eichhornii (xxxii. I xxxn. 383, the eye and tags are visible, and 



383; xxxvii. 1-4). — The case transpa- 

 rent, like glass; rotary organ with five 

 lobes or arms, each furnished with fifteen 

 verticils of cilia ; these arms act occasion- 

 all}^ as prehensile instruments. As the 

 eggs are detained in the case until the 

 young are hatched, Ehrenberg erroneously 

 considers this creature viviparous. In 



over the latter what Ehrenberg caUs gan- 

 glia. The case is discerned with difficulty, 

 from its very transparent natm-e, unless 

 indigo is mixed with the water. 1-36". 

 S. glacialis. — Only one specimen seen 

 without its stem. ' The five arms not 

 furnished with ciliary whorls, but with 

 sino^le bristles. 1-14'". 



The internal organization oi Stephanoceros is well illustrated in XXXVII. 1 : 

 h is the pharyngeal bulb, resting upon a proventriculus or crop c, below 

 which is the maxillary bulb d, containing the jaws ; e is the stomach, with 

 its large cells ; whilst / is the intestine, terminating at the cloaca ; g is the 

 ovary containing ova ; h indicates delicate longitudinal muscles, extending 

 down the peduncle; and tt the water-vascular canals with their vibratile 

 tags. 



In fig. 2 the detached ovary is represented, consisting, as is usual amongst 

 the Rotatoria, of a delicate membranous sac, /, prolonged into an o\dduct. 

 The contained ova are seen in different stages of development. At a is the 

 stroma or granular mass, with its germs ; h is an ovum in the first stage of 



