No. 3. — On Neetonema agile, Verrill. By Henry B. Warn.’ 
CONTENTS 
Page Page 
Dr intronuehonee 1st 2100 4 Body Cavity = s . «198 
TODOS RUHR en, soe OO 5. Nervous System . . . 159 
DiaiSystonianiores BER (Ee AI ETOT Be Brains AURI S01460 
Lie BIOlogy. ars Nadia 139 a Ganglion Cells . 159 
IV. General Morphology . . . . 140 B Dorsal Cells . 165 
T RSS C (o v ui AU y. Fibrous Mass . 166 
motores. RUN P TIT b. Ventral Nerve Cord 167 
V. Anatomy and Histology . . . 143 c. Anal Ganglion . . 169 
i1ocBody Wall i. 067.148 6. Sexual Organs. . . . 171 
MmeCutioula at: Uo iag Ais Malapitan in... rada d 
a. Bristles . . 144 b. Remale.s 0 i ku dae 
B. Scales’... 146) VL Discussion o . ie oos edil 
b. Hypodermis . . . 146 1. Dorsal Cells =... 22% 
a Median Lines . 146 2. Large Ganglion Cells . 180 
heit Muscular Layer . . 148 Q:RowsofHaiss.. u, 181 
2. Alimentary Canal . . 151 4. Muscular Layer . . . 181 
a. (Esophagus . . . 15) 5. Parasitic Nature . . . 182 
b. Intestine . . . . 154| VII. Comparison with other Forms 182 
3. Anterior Chamber . . 156| VIII Bibliography . . . . . . 188 
ISDLONRLIOH OE eph piedhur cuente ee en ar diis atr doc 189 
I. Introduction. 
Fon more than twenty years an interesting pelagic worm has been 
frequently captured at the Newport Marine Laboratory. It was proba- 
bly first seen by Dr. Alexander Agassiz, who encountered it as early as 
1870., His first recorded observations, made in 1871, as well as his 
subsequent studies, have remained, however, in the form of unpublished 
notes and drawings, which were placed at my disposal in June, 1891, 
when I began the present study. Two of these drawings, which illus- 
trate most clearly the external appearance, and show also some of the 
internal organs, are reproduced on Plate I. Figs. 3, 6. 
In 1873 Professor A. E. Verrill published, under tho title “ gen, indet.,” 
a short description of two specimens captured in towing near Wood's 
1 Contributions from the Zoölogical Laboratory of the Museum of Comparative 
Zovlogy, under the direction of E. L Mark, No. XXXII. 
VOL. XXIII. — NO 3. 10 
