2 THE VOYAGE OF H.M.S. CHALLENGER. 



much as I could have liked ; for the same reason several genera, as Bugula, and the 

 whole Ctenostomata, have not been critically examined, and complete comparison with 

 allied species in my collection has not been possible. However, I have been enabled to 

 add particulars of various structures and organs not previously noticed. There is little 

 doubt that Mr. Busk would have noticed many of these had he not been in very failing 

 health during most of the time he was engaged in the preparation of his Eeport, which 

 prevented him making full use of all the modern methods. 



It will be best to give a short resume of the points of chief interest dealt with in 

 this Report, and I should place at the head the fact of a common parenchym cord sur- 

 I'ounding the zocecia of Retepora columnifera (PI. III. fig. 10). This cord is no doubt 

 the equivalent of what Joliet ' calls the endosarc, but which Vigelius ^ would simply call 

 the parenchym, and about which much has been written by Reichert, Claparede, Nitsche, 

 Smitt, and others. In the Chilostomata, however, it has only been known inside the 

 zooecial cell or its connections, usually occurring near the walls, and communicating with 

 the endosarc of the neighbouring zocecia through the rosette plates. The position of this 

 internal endosarc is variable, and changes at diflferent stages of growth, so that sometimes 

 a considerable accumulation is seen inside the walls of growing parts, and at others it is 

 very difficult to trace it. This zooecial parenchym occurs in a second Retepora, and will 

 probably be found in others, thus opening a considerable field of investigation, and the 

 question naturally arises as to whether the older forms had a zoarial endosarc ; also 

 speculation may be made as to its relationship with the chitinous cord of Rhabdopleura, 

 and of the Gymnolaemata. 



In several Reteporw and some other genera there is a gland-like sac attached at each 

 side of the oral aperture (PI. III. figs. 12, 13), and in the avicularian chamber oi Lepralia 

 margaritifera there are two double gland- or sac-like bodies, which may have the same 

 function or origin as those in Retepora. The late Dr. Joliet described an organ in 

 PedicelUna as " organe segmentaire," and thought it was homologous with the interten- 

 tacular organ of Farre, Hincks, and Smitt ; from his short description I do not see 

 the ground for this, but think it should be studied together with the organs just 

 mentioned. 



In papers referred to elsewhere I called attention to the genus Adeonella, containing 

 forms in which characters of primary importance are difi"erent. Mr. Hincks' refers in 

 some detail to this, and in the main points agrees ■sx'ith me, but thinks that I have placed 

 in the restricted genus some species which should be removed ; but now that I have had an 

 opportunity of examining all, they seem to form a natural group with some characters of 

 Adeona on the one side, and of Schizoporella on the other. Although there is much that is 



' L'Histoire naturelle des Bryozoaires des Cotes de France, Archives de Zool. erpe'r., torn. vi. 



- Die Bryozoen gesammelt wahrend der dritten und Nierten Polarfahrt des "Willem Barents," p. 23, &c. 



^ Critical Xotes on the Polyzoa, Ann. and Mag. Xat. Hist., ser. 5, vol. six. p. 150. 



