2o8 Papers from the Marine Biological Laboratory at Tortugas. 



Genus Microporella (part) Hincks, 1877. 



Microporella ciliata (Pallas). 



Pallas, 1766, p. 38 {Eschara ciliata). — Smitt, 1873, p. 26 (Porellina ciliata). — Packard, 

 1867, p. 270 {Lepralia ciliata). — Verrill, 1879^, p. 29 {Porellina ciliata); 

 1875c, p. 53; 1880, p. 190, and 1879, p. 29 {Porellina siellata {or a form of this 

 species).— OsBURN, 1912, p. 233 {M. ciliata), and p. 234 (the variety stellata 

 Verrill). — Levinsen, 1909, p. 328 (discusses genus). 



From 5 to 18 fathoms on shells, corals, etc. One fine colony growing 

 on an egg case of a large mollusk. Smitt records it at various depths from 

 7 to 60 fathoms. It is one of the most widely distributed of all bryozoa 

 and occurs in all oceans. 



Levinsen (1. c.) places this genus in family Escharellidae. 



Genus Smittina Norman, 1903. 

 Smittina trispinosa (Johnston). 



Johnston, 1838, p. 280 {Lepralia trispinosa). — Dawson, 1859, p. 256 {Lepralia 

 trispinosa). — Packard, 1867, p. 67 {Lepralia trispinosa). — Smitt, 1873, 

 p. 59 {Escharella jacotini) , and p. 60 {E. spathulata). — Verrill, 1879&, p. 31; 

 1880, p. 195 {Mucronella jacotini) ; 1875a, p. 514, 1878, p. 305, and 18796, 

 p. 30 {Discopora nitida). — Whiteaves, 1901, p. 106 {Smitlia trispinosa). — 

 Norman, 1903, p. 120 {Smittina nom. nov. for Smiltia preoccupied in Dip- 

 tera). — Osburn, 1912, p. 246 {Smittia trispinosa). 



One of the most abundant and characteristic species in the Tortugas 

 region from low water to 12 fathoms. A cosmopolitan species and dis- 

 tributed all along the Atlantic coast northward to the Arctic region. Smitt 

 recorded it from 13 to 44 fathoms in Florida waters. 



Smitt states (p. 60) "For the peculiarity of the development of the 

 avicularia, the Floridan form, as a distinct variety, I propose to be named 

 Escharella spathulata.^ ^ But variation in the secondary characters of this 

 species here as in many other regions occurs to a bewildering extent. The 

 typical form with the large, pointed avicularia, common in northern waters, 

 is rare, but these are occasionally observed. One beautiful colony growing 

 on the under side of Cupularia guiniensis at 10 fathoms is an almost pure 

 example of Smitt's spathulata. Even the smaller, triangular avicularia 

 figured ^ - Smitt (pi. x, fig. 200) are not represented, but in a few cases 

 very elongated pointed avicularia occupy the place of the long-spatulate 

 form figured by Smitt. Another colony found in the drift is more like 

 Verrill's nitida in the character of the avicularia, which are small, short- 

 pointed, and short oval in form, very much like specimens from the southern 

 New England coast. In a few cases very large spatulate avicularia, as long 

 as the whole zooecium, were observed. In one colony short-triangular avicu- 

 laria were rather regularly disposed in pairs below the orifice with the man- 

 dibles pointing outward. Occasionally the avicularia are almost wanting 

 from a colony, a condition seen in many New England specimens that bear 

 evidence of very rapid growth in a single layer. 



The ooecia vary much with the state of calcification. In younger stages 

 they are coarsely and sometimes very irregularly punctured. This layer 

 may be entirely covered by secondary calcification, when the ooecia present 



