88 THE EOTIFEEA. 



• Genus TKOCHOSPHiEKA, Semper. 



GEN. CH. Solitary, frcc-'sirimmiiiij ; hoAj a perfect sphere; buccal orifice on the 

 spherical surface ; principal wreath dividifig the sphere into two hemispheres, and pass- 

 ing above the buccal orifice ; dorsal gap in the wreath at the pole opjiosite to buccal 

 orifice ; secondary wreath a frmjvtent on tlie under edge of the buccal orifice ; ventral 

 antennae cxlremcltj minute; tube absent. 



T. a;QUAT0KiALi8, Semper. 



(PI. D. fig. 11.) 



Trochosplicura aciuatorialis . . Semper, Stc6. u. Kiill. Zeils-Bd. xxii. 1872, p. 311, Taf. 



xxiv., translated in Mon. Micr. J. vol. xiv. 1875, 

 p. 237, pis. cxx. to cxxii. 



Wlio can complain here tliat a rough wrinkled skin, complicated external form, and 

 huddled-up organs have rendered his utmost cti'orts almost fruitless ? Here is a creature 

 whose outer shape and texture have aUke reached the very acme of simplicity ; the one 

 translucent as the clearest water, the other rounded into a perfect sphere : an 

 animal created as it were for the study of its mterual structure ; its organs all sym- 

 metrically spread apart in due array, just as if a skilfid demonstrator had teased tliem 

 out with delicate needles ; no one overlapping another, and all deftly hung to the walls 

 of a hyaline globe which not only upholds them, but also displays them to the utmost 

 possible advantage ; for it has a band of cilia girdling its entire circumference, and 

 rolling it through the water, so as to present it in every possible pomt of view. 



Trochosphara has a perfectly transparent spherical body with a principal cihary 

 wreath rmming round what may be called the equator, and marking the common 

 boundary of what Prof. Semper calls the " oral " and " ab-oral " hemispheres. In the 

 former lie nearly all the organs of the body ; for only one ners'e-thread and portions 

 of a pair of muscular bands are to be found in the other. At one spot in the equa- 

 torial ring of ciha there is a break in the wreath, and at the opposite extremity of 

 the diameter passing through this spot is the buccal orifice, which has a very small 

 secondary wreath fringing its oral or lower side. 



The various mternal organs are so well displayed in Prof. Semper's figure, that 

 only a few pohits require notice. The trophi, though of somewhat peculiar shape, are 

 maUeo-ramate. The lateral canals end in the cloaca, not in the contractile vesicle ; 

 and this latter, according to Prof. Semper, discbarges itself into the intestme. The 

 nervous system can be well made out. From the nervous ganglion {ng), which lies 

 close to the mastax (mx\, five pairs of nerves pass respectively to the ciliary wreath, 

 buccal orifice, lateral antennse [a'), lateral canals [Ic], and eyes (c) ; while a single 

 iierv'e thread {n) passes to the probable dorsal antenna (a). 



The male is unknowm. 



It is obvious that if the aboral hemisphere were pressed flat, and the oral lengthened 

 out into a cone, we sliould have, in the altered Trochosphara, a Eotiferon somewhat re- 

 sembling one of the Mcliccrtadce. For it would have a buccal orifice laterally placed ; a 

 principal ciliary wreath surrounding the body, with a gap in it on what would then be 

 the dorsal side ; a portion of a secondary wreath passing round the edge of the buccal 

 orifice ; troplii of a IMelicertan type ; two minute ventral antenmc, and a single dorsal one. 

 On the other hand, the absence of an attached foot, and of a complete secondary wreath, 

 and the difference of habit, make it no easy matter to say where Trochosphara should be 

 placed ; on the whole, I think it should be put among the Melicertada near Megalotrocha 

 and ConocJiilus. 



Length. Diameter of sphere, ^\ inch. Habitat. Ditches in the rice fields of 

 Zamboanga, in the Philippine Islands (Prof. Semper) : rare. 



