364 APPENDIX. 



cells upon which the ovicells are placed are always gemi- 

 nate, that is to say, hare a smaller cell growing out from 

 one side. 



6. Calpidium, n. gen. Tab. i. iig. 3 — 5. 



Char. — Cells with an avicularium on each side; with 

 two or three distinct mouths, arising one from the upper 

 part of another, in a linear series, all facing the same way, 

 and forming dichotomously-divided branches ; cells at the 

 bifurcations single; ovicells — ? 



This very pecuhar genus, remarkable as it is, seems 

 hitherto to have escaped notice. It is distinguishable 

 from Catenicella, in the first place, by the anomalous cir- 

 cumstance that each cell is furnished with two or more, 

 usually three, distinct keyhole-shaped mouths, and is 

 doubtless inhabited by three distinct iudividuals. Whether 

 these are separated from each other by internal partitions 

 is unknown, but the closest examiuation of cells rendered 

 transparent by means of acid fails to discover such. In 

 cells thus prepared, there are apparent, however, three 

 distinct masses, reaching from the bottom of the cell to 

 each orifice, and which are probably the remains either of 

 the body or of the retractor muscles of the animals. An- 

 other point of difference from Catenicella is the non-gemi- 

 nation of the cell at the dichotomy of a branch. The 

 avicularia, moreover, do not form lateral projections, but 

 are sessile, or imbedded, as it were, in the sides of the cell 

 immediately below the upper angles. 



1. C. ornatum, n. sp. Tab. i. fig. 3 — 5. 



Cells triangular-urn shaped, very broad above, with a 

 straight border, much compressed ; mouths, 2 — 3, keyhole 

 shaped. Five fenestrse below each mouth; numerous 

 branching bands on the back of the cell. 



Hab. — Bass Strait, 45 fathoms. 



This curious species is the only one belonging to the 

 geniis. The cells are very large, regular, and uniform. 



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