170 Rev. T. Hincks's Contrilmtionn totoards a 



of Steganoiiorella on tlic ground tliat no one has demonstratecT 

 tlie presence of reproductive bodies within it. This may be 

 true, and may be easily explained. All the probabilities point 

 to this interpretation as the true one. The Cheilostomata are 

 generally furnished with external ooccia in which the embryos 

 complete their development. These are wanting in Stegano- 

 porella, and it is reasonable to suppose that the internal 

 chamber provided hy the peculiar structure of the zooecium 

 may be the equivalent. Amongst the ordinary Cheilostomata 

 species occur which are destitute of ooecia of the ordinary 

 type ; their function is discharged by specially modified 

 zooecia, which are commonly distinguished by the larger size 

 and sometimes the altered shape of the orifice. In the case of 

 StcganojwreUa, as Busk has pointed out*, the upper or ooecial 

 compartment is more developed in some of the zooecia than in 

 others, and the difference is marked by a difference in the size 

 and pattern of the chitinous framework of the operculum. 

 These structural variations throw light one on the other. 



On p. 86 (sep.) a list has been given of the species belonging 

 to the genus SteganoporeJla ; but when it was prepared the 

 structure of the group to which this genus belongs had not 

 been thoroughly investigated, and important changes have 

 since been made in the classification. The following table 

 shows these changes : — Genus SteganopORELLA : Species 

 S. magnilahriSy 8. Neozelamca. Genus Thalamopoeella, 

 Hincks : Species T. Rozieri^ Audouin, and its forms gothica^ 

 Indica, and fahifera \ T. Smittii, Hincks; T. Jervoisii, 

 Hincks ; T. steganoporotdes, Goldstein. 



Micropora ehngata, Hincks, and M. jjerforatay MacGillivray, 

 were wrongly referred to Steganoporella. Vincularia Novce- 

 HoUandioi, Goldstein, which was doubtfully included in 

 Steganoporella^ is ThalamoporeUaRozieri^ foYmindica^ Hincks. 



Ibid. (p. 86 Sep.). 

 Monoporella albicans^ sp. n. 



Ibid. (p. 89 Sep.). 

 Schizoporella aperta, sp. n. 



The forms described under the above names agree in general 

 character and in most of the details of structure ; but as I was 

 unable to detect an oral sinus in my specimen of the former, 

 it seemed necessary to refer it to Monoporella, noting the 

 remarkable similarity in other points between the two forms. 



* ' Cliallenger ' Report, part i. p. 74. 



