i8 



tactile processes at its distal end. Retracted lophophore nearly circular, with 9 tentacles. The 

 contracted stalk is about the same length as the calyx, its wal] possessing a layer of strong 

 longitudinal muscles : proximal end of stalk more or less pointed, without foot-gland in the 

 adult state. Buds not numerous, not more than two present on the side hearing the oldest 

 bud. Gonads? 



The Cheilostome in which this species of Loxosoma has been found is the form which 

 was described by Busk l ) as Lepralia cclleporoides. The middle of the frontal surface of this 

 species is occupied by a very large "median pore", of variable shape. The pore, which is 

 shown by Busk in PI. XVII, fig. \b, is morphologically an "ascopore" 2 ), since I find that it 

 is the external opening of a large compensation-sac, which contains the Loxosoma. The occur- 

 rence of Entoprocta as normal inhabitants of the compensation-sac of a Cheilostome has not 

 previously been recorded, so far as I am aware. The unusually large size of the ascopore in 

 L. cclleporoides renders the compensation-sac an eligible dwelling-place for the Loxosoma, which 

 has no difficulty in protruding its calyx through the one of the lobes of the ascopore to the 

 outer water, as shown by several individuals which have died in this extended attitude. It 

 need hardly be pointed out that the stalk is correspondingly elongated in such specimens. 



In the retracted condition in which the great majority of the individuals have been 

 preserved, the proximal end of the stalk is usually attached to one side of the compensation- 

 sac, the calyx lying just underneath the ascopore, through which its tactile processes are com- 

 monly visible. The aboral surface of the Loxosoma lies uppermost, so that the orifice of the 

 vestibule faces the cavity of the compensation-sac. In many parts of the host the majority of 

 the zooecia, or all of them, contain Loxosoma ; from one to three individuals occuring in a 

 single compensation-sac, the calyces all radiating in the direction of the ascopore. 



The Loxosoma, whose cave-dwelling habit I have indicated by the specific name sug- 

 gested, is not the only organism which has taken advantage of the large size of the ascopore ; 

 since, in many zooecia, one or more of the tubes of the Infusorian Folliculina are attached 

 to the wall of the compensation-sac, near its orifice ; the tube projecting through the ascopore 

 to the outer water. Where Folliculina occurs I have not found the Loxosoma, although some 

 zooecia contain neither of the two organisms. The Loxosoma is usually absent in zooecia which 

 have lost their polypides. 



In many cases the tactile processes of the Loxosoma are two in number, disposed 

 symmetrically, as in figs 17 and 18. But in other cases three may be present; or there may 

 be two tactile processes, both situated on one side of the middle line ; or four, symmetrically 

 disposed. 



In many species of Loxosoma the tentacles are present in an even number. But in the 

 present species nine tentacles were counted in all cases where the number was definitely 

 ascertainable. Of these, four tentacles belong to the proximal end of the lophophore, and the 

 odd tentacle is the distal one. 



The form of an old bud is shown in fig. 17, where a young bud is seen on the distal 



ij Bi -k. ('.., 1884, 'Challenger' Report, Pt XXX, p. 142. 



2) LEVINSEN, G. M. R., 1909, "Morph. and Syst. Stud. Cheilostomatous Biyozoa", Copenhagen, p. V. 



18 



