NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
67 
example, in which the zooecial cells are relatively very elongate, the tentacles are 
short and never exceed a third of the length of the brvozooid. Finally they are 
of a medium length in other species and have about two-fifths of the length of the 
bryozooid. The dimensions in thickness are also quite variable. Yet it seems that 
they are proportional to the dimensions of the general cavity and inversely to 
the number of the tentacles.” (Translated from Calvet, 1900. ) J 
We give for each species the exterior micrometric dimensions of the zooecia ; our 
measurements only express the average or the most frequent measurements. We 
are not able to draw up any general law. Very frequently the length is double the 
width; the other relations are more rare. There must be some very interesting 
studies to be made along this line, but we have not had the time to do so. and, more- 
over, a zoological basis is wanting absolutely. 
Total regeneration. — The regeneration of the polypide is a phenomenon well 
known in bryozoology ; it leaves no trace in the Cheilostomata. Sometimes, for causes 
unknown, it is the entire individual which is regenerated. This total regeneration 
leaves some external traces. It was thoroughly studied by Levinsen in 1907, 1 2 and 
he cited numerous examples. In the course of our w T ork we have noted some inter- 
esting observations which confirm those of Levinsen. Following are some of the 
cases : 
1. Replacement of a zooecium by an avicularium. 
Hincksina meg av i eu laria , new species (pi. 23, fig. 1). 
Ldcerna hexagonalis , new species (pi. 44, fig. 20). 
2. Female polypide succeeding a male polypide. 
Hincksina elegans, new species (pi. 80, fig. 15). 
3. Female zooecium inverted and succeeding a male polypide. 
Membraniporidra laticella , new species (pi. 26, fig. 5). 
4. Replacement of a zooecium by a zooecium. 
Floridinella vicksb irgica. Canu and Bassler (pi. 82, fig. 26). 
5. Replacement of an ordinary zooecium by an inverted zooecium. 
Membraniporidra laticella, new species (pi. 26, fig. 4). 
6. Replacement of a normal zooecium by a calcified zooecium. 
Euritina tecta , new species (pi. 5, fig. 2). 
Velumella plicata , new species (pi. 34, fig. 4). 
7. Replacement of an avicularian zooecium by another avicularian zooecium. 
Schizomavella granulosa, new species (pi. 46, fig. 15). 
8. Triple regeneration. 
Grammella crassimarginata Flincks (pi. 24, fig. 13). 
Alderina crassa, new species (pi. 29, fig. 7). 
The effecting cause of total regeneration is unknown. 
1 Contributions a l’historie naturelle des Bryozoaires ectoproctes marins, Travaux dfinstitnt de 
Zoologie de l’Universite de Montpelier, Memoire No. 8, p. 183. 
2 1907. Levinsen, Sur la regeneration totale des Bryozoaires, Bulletin Academie Royal des sciences et 
des lettres de Danemark, pp. 151-160. 
