OVICELLS OF CrCLOSTOMATOUS BRYOZOA. 



277 



plete, so that frequently this important character cannot be made 

 out ; and in my specimen I could not find any opening, but one 

 of the lateral zooecial tubes is much larger than usual, and looked 

 as though this change was connected with the functions of the 

 ovicell. I therefore wrote to Mr. Kirkpatrick, of the British 

 Museum, explaining what I had seen in my specimens, and asked 

 him if he would look at those in the Museum. He kindly did so 

 at once, and wrote that he examined ten ovicells, " and found 

 in each instance that the last one or two zocecia of a series in 

 proximity to an ovicell are not only enlarged, but considerably 

 altered in direction. In eight instances the tube curved for- 

 wards and uj)wards so as to open on the anterior surface." In 

 two the tubes opened laterally. " In every case the wide tube 

 is to some extent connate to a zooDcial series ; but in some cases 

 the former curves away from the latter in such a way as to make 

 the wide tube appear to be part of the ovicell, and not a meta- 

 morphosed zooecium " *. 



I have already referred (Ann. Mag. Nat. Hist. ser. 5, vol. xx. 

 p. 255) to the fact that the ovicells of the Cyclostomata have 

 the surface nearly always perforated with much more numerous 

 pores than the rest of the zoarium. In the present case the 

 ridges are narrower and the pits somewhat finer than on the rest of 

 the dorsal surface ; and at the base of these pits, which are some- 

 times spoken of as pores, there are several fine pores, whereas in 

 the pits on the dorsal surface, except when elongated, there is 

 but one pore at the base. It will thus be seen that in this case 

 the pores on the ovicell are much more numerous than on the 

 rest of the zoarium. 



Figures (1 and 3) are given from calcined specimens of tlie 

 front and back of the zoarium, and I consider that preparations 

 should be thus made wherever there is available material; for 

 figuring with all the organic integument is like taking a photo- 

 graph of a lady with a thick veil down. Calcined specimens can 

 be directly compared with fossils. 



The anterior surface has large pores, or rather pits, following the 

 lines of the zooecia, with one or two pores at the base of the pit. 

 The way in which the ornamented appearance is formed is shown 

 more clearly in this species than in any other I have seen. At 



* In the ' Challenger ' specimens in Edinburgh ovicells occur in a large 

 number of cases, with a large lateral tube curving forwards. 



22* 



