DEPARTMENT OF MARIXE BIOLOGY. 129 



Numerous dredgings were made in shallow water, down to 20 fathoms, with 

 the Sea Horse and Physalia. No attempt was made to go beyond the shelf 

 surrounding the keys ; in fact, practically all the collecting was done in less 

 than 12 fathoms, since it was observed that below this depth the character of 

 the fauna rapidly approaches that of the deeper water. 



The conditions for the growth of Bryozoa are not particularly favorable, 

 owing to the great amount of coral mud which settles on everything in quieter 

 water, while in many places the shifting coral sands prevent the growth of 

 any sessile form of life. ^Material taken from the piles and the m.oat was 

 usually so covered with coral mud as to be unrecognizable until thoroughly 

 washed under a tap, and in the case of Ctenostomes it was found necessary 

 to treat with weak acid to dissolve away the layer of calcareous mud before 

 the characters could be ascertained. The cleanest and best-developed speci- 

 mens as well as the greatest number of species were dredged on sponge beds 

 at 5 to 10 fathoms. Many species were found growing on sponges. 



The writer has not had opportunity to study the collection carefully, con- 

 sequently the following account of the species is merely tentative. 



Fifty or more species were taken in the limited region above mentioned. 

 Of this number only 30 have as yet been recorded from the West Indian 

 fauna. The 20 or more remaining species are nearly all new, at least to the 

 North American fauna. How many of them are as yet undescribed remains 

 to be determined. 



ENDOPROCTA. 



Barentsia (Ascopodaria) discreta Busk. This, the only species of endo- 

 procta taken, has hitherto been recorded only from Tristan da Cunha {Chal- 

 lenger), but the writer has taken it also at Woods Hole, Alassachusetts, and 

 Beaufort, North Carolina. No endoprocts are mentioned in Smitt's paper. 



ECTOPROCTA. 



The Ctenostomes are well represented by 5 genera and at least 6 species. 

 All of these species and 3 of the genera are new to our east coast fauna. 



Zoobotryon pelhicidus Ehrenberg. This fine species forms large colonies 

 on the piles and in the moat at Fort Jefferson. 



Cylindrcecium sp. occurs in great abundance, sometimes covering shells and 

 algae with a dense coating of the erect tubes. 



Bozverhankia candata Hincks occurs on piles and down to 10 fathoms. 



Amathia spiralis Lamouroux ( ?) occurs plentifully in the dredgings. and 

 a smaller species with it. 



InPourtales's collection Smitt found only i ctenostome, and it was not in 

 condition to identify beyond the genus Serialaria. 



Of Cyclostomes only a single species, Crisia ramosa Harmer (?), occurs 

 among my material, while Smitt recorded 10 species belonging to 7 genera, 

 all from deeper water. 



The Chilostomes are, as everywhere, the predominant group, and they pass 

 through all the usual types of growth from creeping and incrusting to various 

 erect forms. The following genera have been noted: /Btea, Catenaria, Far- 

 cimia, Scrupocellaria, Caherea, Bugula, Beania (?), Cupularia, Thala'mopo- 

 rella, Steganoporella, Smiitipora, Memhranipora, Cribrilina, Microporella, 

 Hippothoa, Schizoporella, Cellepora, Mucronella, Smittia, Lepralia, and 

 Retepora. 



