The Bryozoa of the Tortugas Islands, Florida. 193 



Genus Membranipora Blainville, 1834. 



Membranipora membranacea (Linne). 



Linn6, 1766-68, p. 1301 {Flustra membranacea), — Packard, 1867, p. 274. — Robertson, 

 1908, p. 267. — Norman, 1909, p. 286. 



One colony on the bottom of a skiff. In ev^ery respect this colony 

 agrees with European specimens in my collection, except that there is a 

 very slight extension of the calcification over the area at the base of some 

 of the zooecia. This is so slight, however, that I can not consider it of 

 specific value. The species was not listed for Floridian waters by Smitt, 

 nor was it taken by the writer at Woods Hole, Massachusetts, in several 

 years collecting. 



Packard recorded it from the Labrador coast. It is a common European 

 species, occurring as far south as Madeira (Norman). It is also found in 

 Australia and New Zealand, and Miss Robertson (1908) states that on the 

 Pacific coast of North America it occurs from California to Alaska. 



? Membranipora lacroixii (Audouin). 



AuDOUiN, 1826, p. 240 {Flustra lacroixii). — Busk, 1852-4, vol. 2, pi. i. — Dawson, 1859, 

 p. 256. — Packard, 1867, p. 8. — Smitt, 1873, p. 18. — Jelly, 1889, p. 162 

 {M. reticulum). — Waters, 1898, p. 697. — Whiteaves, 1901, p. 97. — Robert- 

 son, 1908, p. 261. — OSBURN, I912, p. 227. 



Taken in drift incrusting the carapace and legs of a large crab, and at 

 8 fathoms on shell. The specimens taken at Tortugas are much more 

 heavily calcified than those from Massachusetts and between the zooecia 

 are numerous, roughly triangular prominences with triangular, membranous 

 areas, as figured by Busk (1. c, pi. i), while these are almost wanting in the 

 Massachusetts specimens. Examination of the reverse side of the zooecium, 

 however, reveals the transparent circles and the irregular projections 

 described by Waters (1. c). 



There has been much difference of opinion concerning this species and 

 there can be but little certainty in regard to many earlier records, such, for 

 example, as those of Dawson and Packard. Smitt's figures of Florida 

 specimens seem, without question, to represent the same species as my own, 

 though the dorsal surface is not shown. The range on the eastern coast of 

 North America is from Florida to the Gulf of St. Lawrence, or to Labrador, 

 if Packard's record is valid. Elsewhere it is known from Europe, New 

 Zealand, and from California northward to Alaska. 



Membranipora tehuelcha (d'Orbigny). 



D'Orbigny, 1839, pi. 17 {Flustra lehuelcha). — Bosc, 1802, p. 118 {Flustra tuberculata) . 

 — Jelly, 1889, p. 167 {M. tehuelcha) and p. 168 {M. tuberculata). — Waters, 

 1898, p. 674. — Verrill, 1900, p. 594 {Biflustra dentata). — Norman, 1909, 

 p. 286 {Membranipora tuberculata) .--<)sbvrn , 1912, p. 231. 



This species is found on Sargassiini bacciferum (gulfweed) wherever it 



floats. It is abundant at the Tortugas. Verrill notes its occurrence at 



Bermuda, under the name of Biflustra dentata, as "common on Sargassum 



found upon the beaches." Smitt did not record it for the Florida region. 



14 



