BBYOZOA from: fbanz-josep land. 169 



synonym, but from the description that seems to be a much 

 smaller and more delicate species. However, as Beteporidea 

 ramosa, d'Orb., is Hornera, MacGrillivray's species cannot 

 stand. 



A specimen from Naples is very much like the H. lichenoides, 

 having similar dorsal ovicells, and has been called S. lichenoides ; 

 but I propose to separate it as JS. mediterranea. It has the 

 zooecia irregularly placed ; the outer zooecia are much the longest, 

 the inner ones are not much raised, and the border is entire. 

 It may be the S. serrata of Meneghini, but the name serrata 

 has been previously employed by Eeuss. S. horealis, Busk, 

 from Shetland, has been frequently placed as a synonym of 

 H. lichenoides, Pontop. ; but I am not confident that this is the 

 case, as I find in an authentic specimen sent to me so named by 

 Canon Norman that the zooecia are smaller, measuring internally 

 about 0*08 mm., and they are more abundant than in the Arctic 

 II. lichenoides. A considerable number of specimens should 

 be examined to see what is the range of variation. 



The dorsal position of the ovicell obtains in but few genera, 

 and therefore the comparison with other Cyclostomata has a 

 special importance, as it cannot arise through a slight modifica- 

 tion of a zooecium, though there must at some time have been 

 a communication with a zooecium ; and the adaptive changes 

 must have been much greater than in such genera as Crisia and 

 Idmonea. 



A comparison with the ovaria of Diastopora intricaria, Smitt, 

 ah'eady described, shows some important differences. In that 

 species we have seen that the number of embryos in an ovicell is 

 very large, being over one hundred, whereas in the ovicell of 

 S. lichenoides it would not seem, from my sections, to exceed 

 about ten, and. these are much larger than those of Diastopora 

 intricaria, probably about four times as large, and. these last are 

 much further developed. Ostroumoff* says that the larvae of 

 Hornera are the largest of the marine Ectoproct Bryozoa with 

 which he is acquainted, measuring 0'48 mm., and that in size 

 downwards are Hornera, Tuhulipora, Frondipora, Discoporella, 

 and Crisia, which last are only 0*07 mm. The protopLismic 

 reticulum is attached to the wall of the ovicell, and not only 

 surrounds the group of larvae but passes between the individuals, 



* " Zur Entwickelungsgeschichte der Cyclostomeu Seebryozoen," Mittheil. 

 Zool. Station zu Neapel, toI. vii. p. 180. 



