2 BULLETIN OF THE 
tory at Wood’s Holl, Mass., during the summer of 1889, and while at 
Mr Agassiz’s Newport Laboratory during the summer of 1890. To my 
instructor, Dr. E. L. Mark, for many valuable suggestions during the 
progress of my work and the writing of this paper, to Mr. Alexander 
Agassiz, for the kind hospitality accorded me at his Newport Laboratory, 
and to Hon. Marshall McDonald, United States Commissioner of Fish 
and Fisheries, and Dr. H. V. Wilson, Assistant at Wood’s Holl, for fa- 
vors shown me while at the Wood’s Holl Laboratory, I make grateful 
acknowledgment of my indebtedness. 
A word as to localities. The marine Bryozoa were found especially 
abundant at Newport on floating eel-grass in the cove and on the piles 
of the wharf. The embryos of Cristatella and Plumatella were found in 
colonies which literally covered the bottom of some parts of the south 
or shady side of Trinity Lake, Pound Ridge, New York. They occur 
especially in densely shaded and fairly deep water near the shore. 
The Gymnolemata present many difficulties to finer technique. They 
possess a chitinous covering, often very thick, and frequently, in addition, 
a calcarous skeleton. When the latter is present, picro-nitric acid mixed 
with sea water is a fairly good fixing reagent ; when it is absent, hot cor- 
rosive sublimate was most serviceable, The objects must be transferred 
through the grades of alcohol with extreme caution, to prevent the col- 
lapse of the ectocyst. I used the chloroform-paraffin method of em- 
bedding in order to make transfers more gradual at this stage. Some 
difficulty was experienced in staining such small objects on the slide, since 
the tissues are very loosely associated ; and on the other hand in toto 
staining is unsatisfactory in some cases, owing to impenetrability of the 
ectocyst. Often it-was necessary to open the body cavity of each indi- 
vidual by means of a sharp knife or needle. The best results were 
obtained with alcoholic dyes like Kleinenberg’s hematoxylin and 
Mayer’s cochineal; although Ehrlich’s hematoxylin was often used 
with success. 
II. Budding in Paludicella. 
J. ARCHITECTURE or THE STOCK. 
Paludicella, as is well known, occurs in quiet streams and forms 
stocks on the under surfaces of stones and other objects. Seen with the 
naked eye these stocks appear as a fine lacework, composed of constantly 
branching lines of individuals, Some of the stocks which I have meas- 
ured are over 25 mm. in length along their greatest diameter. 
