18 REPOKT ON THE PENNATULIDA. 



For digestion to take place it is necessary for there to be absolute 

 contact between the gland-cells of the filaments and the food ; from 

 which Dr. Krukenberg concludes that digestion is not effected by 

 means of a fluid secretion poured out over the food, but by the direct 

 action of the cells themselves. Watery or glycerine extracts of the 

 mesenterial filaments of Sarjartia or Antliea are found to digest fibrin 

 rapidly at a temperature of 100° -105° F. 



From the above account, which we have quoted because it is the 

 only one based on direct physiological experiments, and also because 

 it appears to be as yet but little known in this country, there can no 

 longer be any doubt as to the function of these hitherto mysterious 

 mesenterial filaments. 



p. The Reproductive Organs. The sexes among the Pennatulida are 

 distinct so far as is as yet known, the polypes of each individual Sea-pen 

 being either all male or all female.* Of the specimens of Funicnlina 

 obtained living at Oban the two larger ones, which alone have been 

 examined for the purpose, are both females, a circumstance we much 

 regret, inasmuch as no description of a male FunicuUna has yet 

 appeared ; the statement that the sexes are distinct resting merely 

 on the analogy furnished by allied genera such as Haliareptrum f and 

 PennatuJa,\ and on the fact that in the female specimens described, all 

 the polypes examined bore eggs. As we shall find when dealing with 

 the historical portion of our subject, only a very limited number of 

 specimens of FunicuUna have yet been examined with any care, so that 

 it is hardly safe to generalise concerning the apparent rarity of male 

 specimens ; but it may well be that the male pens are either really less 

 numerous than the female, or else that they are as a rule smaller, and. 

 therefore disregarded. We trust that the Society will on some future 

 occasion be able to determine this point. 



The ovaries of FunicuUna (Figs. 10 and 15) are the free edges of 

 the six mesenteries which bear, higher up, the short mesenterial 

 filaments. The ova, or eggs (t), are developed as little prominences 

 attached by short stalks to the edges of the mesenteries, from which, 

 when ripe, they become detached, and then lie free in the body-cavity, 

 as shown in Fig. 10. 



Each ovum is apparently a single endodermal cell, which becomes 

 bigger than its neighbours, and so projects above the surface of the 

 ovary : each is, from a very early period, enclosed in a thin 

 capsule, very similar in appearance and in behaviour with staining 

 fluids to the connective tissue mesodermal lamella of the mesentery ; 

 though whether it is actually developed from this lamella, as main- 

 tained by the Hertwigs § in the case of the Anemones, we have not 



♦ Kolliker : Op. cit. 



i Kolliker : Op. cit., pp. 147-172, and Plate XI., Pig. 95, Plate XII., Fig. 94. 

 I An account of the male Fennatula, of which no description has hitherto 

 been published, is given in the second part of this Report. 

 § O. und R. Hertwig : Op. cit. 



