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narrower than the zooecium and, like the vestibule, about half the length of the fully retracted 

 zooecium; bearing a well developed collar. Tentacles 8, bent distally during retraction. Oeso- 

 phagus long, folded on the pharynx when the polypide is retracted. Gizzard wanting. 



This species was originally described by Heller from the Adriatic. I should hardly have 

 ventured to refer the 'Siboga' specimens to it if it had not been for the evidence of specimens 

 from Naples 1 ) in the collections of the British Museum (88. ii. 9. 38) and the University Museum 

 of Zoology, Cambridge. These agree so closely with the Malay specimens, even in the character 

 of the branching, that I am unable to detect any differences of importance. The groups of 

 zooecia shown by Heller in PI. VI, fig. 3 have a close resemblance to those figured in the 

 present Report. The lateral internodes are represented by Heller as being almost spherical, 

 although the Xeapolitan specimens agree closely with those from the 'Siboga' collection in their 

 form. When Heller describes the zooecia as somewhat smaller at their distal end (his fig. 3«) 

 he is 110 doubt alluding to zooecia like those shown in my own figs 19, 20. 



The stolon of the Malay specimens is narrow, measuring about 45 u. in diameter; and 

 the older parts have a thick, chitinous wall. The mode of branching is represented in fig. 15, 

 from which it will be seen that it is identical with that of a specimen from Naples which has 

 been figured by Waters 3 ). The parent-internode is marked off by a distal diaphragm, but there 

 is 110 structure of this kind at the proximal end of the dilated portion. It gives off a pair of 

 lateral branches, which in the specimen figured are each composed of two short internodes, 

 prolonged into a stolon distally. Each of these internodes gives off a pair of lateral branches 

 of similar constitution. The distal internode of each secondary branch commonly gives rise to 

 (a) a distal stolon, (ó) a pair of zooecia, (V) a pair of lateral stolons situated just proximally to 

 the zooecia. This arrangement is, however, not constant, and a median zooecium may be formed 

 distally in addition to a distal stolon, which comes off on the basal side of the zooecium. Other 

 zooecia are given off by the other internodes of the system. 



In fully developed groups of zooecia (fig. 1 3) it is usually difficult to ascertain the details 

 of the branching, which may perhaps be more complex than in the specimen shown in fig. 15. 

 In these groups the zooecia vary in form according to their state of development. The young 

 zooecia are almost spherical (figs 14, 15); but the old ones, with functional polypides, have 

 the form which has been described above as typical (figs 13, 16). 



In a considerable number of cases the zooecia have died with the kamptoderm everted, 

 as shown in fig. 17. This region is less than half the width of the rest of the zooecium, and 

 is terminated by the collar, which is conical in form and has strongly marked ribs or folds. 

 Zooecia in this condition usually show some indication of degeneration of the polypide, the first 

 evidence of which is seen in the degeneration of the vestibule. There seems reason to believe 

 that the collar is thrown off after this stage has been reached : — a process which I believe 

 to take place commonly in Ctenostomata. In a later stage, when the histolysis of the polypide 

 has advanced, the zooecia have the form represented in figs 19, 20 and also in Heller's fig. 3^. 

 The everted kamptoperm has become short and thick walled, and is usually marked by circular 



1) Cf. also Vine, 1. c. 



2) Waters, A. W., 1910, 1. c. 



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