CTENOPHORA. 



satisfactory. An after-fixation with corrosive sublimate, which I have tried on some of the specimens, 

 appeared to have rather a good effect. Upon the whole it must be said that the conditions for stud- 

 ying the histology of the animal were not altogether bad and I hope it will be found that the infor- 

 mation I have been able to give iu this regard is not quite without value. 



Turning now to the description of the animal I shall begin with the grown specimens, their 

 anatomy and histology, taking thereafter the development and the anatomy of the young. 



A. Anatomy and histology of the grown animal. 



The shape of the animal is most unlike that of any Ctenophore previously known. As seen 

 from the figures on PI. I it is elongated in the transverse or tentacular plane, rather compressed in 

 the sagittal plane. In the middle of the uearl)- flat upper side is seen a small pore, which leads 

 down to the otolith or statocyst (PI. i. Figs. 6—8, s.), and along each side there are four, more or less 

 prominent, knobs, of a rather compact nature — the genital organs. They are placed opposite one 

 another, appearing thus paired, there being two pairs to each side of the statocyst On each of them 

 is a generally rather distinct, longitudinal slit-like opening {PI. i. P'igs. 6, 7, 9. i.). At each end, below 

 the outer pair of genital organs, lies a large, yellow body, from which proceeds a thread-like prolon- 

 gation; this is the tentacle apparatus. Each end of the body is erected into a curious vertical pro- 

 longation, like a chimney-top'), through which the tentacle may be seen to project. Below the genital 

 organs there are on each side, in the larger specimens, a varying number of more or less prominent 

 knobs, less compact looking than the genital organs; they are eggs or embryos, contained in their 

 brood chambers. The transparent walls of the body, especially on the chimneys, are seen to contain 

 irregular, branching canals, which prove to be part of the gastrovascnlar system. The underside of 

 the animal forms an irregularly folded basal surface, iu the middle of which is an elongate (in the 

 tentacular plane), more or less open, sometimes even apparently quite closed slit; it leads to a rather 

 large cavity with irregularly folded walls ; from the roof of the cavity some thick folds hang down, 

 and in the middle of these folds is found a narrow, transverse (in the sagittal plane) slit — the mouth 

 opening (PL III. Figs. 5, 11.). The cavity is in open connection with the "chimney.s" (PI. III. F"^ig. 11 o. f., 

 Pi. VI. Fig. 8 o. f.), which represent secondary mouths, the true mouth having become partially inca- 

 pable of performing its functions through the sessile habit of the animal. 



No trace of colour is found in the preserved specimens. As the formaline otherwise generally 

 preserves the colour very well, it may be concluded that the living animal is quite colourless. That it 

 is also quite clear and transparent (with the exception of the genital organs and the tentacle appar- 

 atus) is beyond doubt. 



The size of the largest specimens was nearly ao"'" in length (transverse plane), 5""" width (the 

 sagittal plane); the height of the "chimneys" was ca. 10'"", the height in the middle of the body 5""". 

 (These measurements apply to the specimens when still in formaline; through the later transferring 

 to alcohol they have become somewhat smaller). 



') In the preliminary description (loc. cit.) I have designated this vertical prolongation as a "funnel". This is less 

 fortunate, because the infundibulum is otherwise called the funnel and thus a confusion might easily take place. It is 

 therefore thought better to speak of this tower-like vertical prolongation as the 'chimney". 



