320 H. JAMES-CLARK ON THE AFFINITIES OF SPONGES. 



The contractile vesicles (cv) are two in number. They lie between the second and posterior 

 thirds of the body, usually on opposite sides, and close to the surface. In aspect and 

 rate of systole they resemble those of Codosiga pidcherrimus, but they are a little smaller in 

 proportion to the size of the animalcule. Sometimes the protean changes of the body are 

 so extensive as to throw the two vesicles into line with each other in an anteroposterior 

 direction, but they hold this position only temporarily, and soon return to their normal 

 relations. 



The calyx (c, c\ c 2 ) has the general shape and proportions of a champagne glass, and ap- 

 pears to be hollow to the very bottom (c 2 ) of its pedicel-like, inferior third. Anteriorly it is 

 truncate, smooth, and flares (c 1 ) quite strongly. About the middle it bulges very sensibly, 

 and thence tapers gradually into a slender posterior third (c 2 ), but expands again slightly as 

 it terminates upon its place of attachment. It is colorless, excessively transparent, and 

 exhibits considerable flexibility under the movements of the body ; apparently having the 

 consistency of a mere film. 



§ 8. Salpingceca makinus, nov. sp. 

 (Plate IX., figs. 28-32 a .) 



The remarkable generic resemblance of this species to Codosiga has already (p. 315) been 

 commented upon. It is very common, especially upon the marine Hydro-Medusa Dyna- 

 menapumila. Lamx., but is so excessively minute, and withal so transparent, excepting the 

 body proper, that under a magnifying power of five hundred diameters it appears to the 

 casual observer like a mere globular speck. It was discovered when searching after speci- 

 mens of Codonceca costata with a power of eight hundred diameters. Although sometimes 

 met with in groups of forty or fifty, it always appeared single. In its general aspect it may 

 be compared to an oval flask which is supported by a slender stem (pd), and has a broad 

 funnel mserted in its mouth. Upon close inspection we find that the funnel (b) is a direct 

 projection from the body which hangs freely within the flask (c, c\), and is in no way con- 

 nected with the latter. 



The lody proper has a dark fuscous color, and consequently is quite conspicuous. It is 

 mainly oval in shape, but is constricted anteriorly into a short thick neck (/) which termi- 

 nates in a truncate front. It hangs quite loosely within the calicle (c), and usually at a con- 

 siderable distance from its parietes, but at the mouth (figs. 31, 32, c 1 ) of the latter the 

 neck (i) presses so closely against it as to seem, without the most careful scrutiny, to form a 

 continuation with it. Occasionally, however, the neck narrows and retreats from the aper- 

 ture of the calicle to that degree which allows a clear and unmistakable view (fio-. 32) of 

 the relations of the former to the latter. 



The collar (b), which has just now been likened to a funnel set in the mouth of the flask- 

 shaped calyx, is most frequently seen in a very broadly expanded state (fig. 28, b); in out- 

 line resembling a low, obtuse-angled, truncate cone inverted upon the front of the body It 

 arises from the extreme circular margin of the head (/), and, widening to about twice" the 

 equatorial diameter of the calyx (<•), terminates in a smooth edge at an altitude which is 

 hardly equal to one quarter of the width of its distal expanse. It is hyaline, and so ex- 

 tremely thin and filmy as to require the most careful manipulation of the light, even with 

 so high a power as eight hundred diameters, in order to define its boundaries clearly. Its 



