194 



CHAS. B. WILSON. 



47. Watase, S.— " Studies on Ceplialopods : I. Cleavage of the Ovum/' 



* Journ, Morph.,' vol. iv, No. 3, 1891. 



48. Whitman, C. O.— "The Embryology of Clepsine," 'Quart. Journ.' 



Micr. Sci.,' vol. xviii, 1878. 



49. Wilson, C. B.—" Activities in Mesenchyme Cells of Certain Larvae/ 



'Zool. Bull.,' vol. ii. No. 1, 1898. 



50. Wilson, E. B.— " Observations on the Early Developmental Stages of 



some Polychajtous Annelids/' ' Stud. Biol. Lab. Johns Hopkins Univ.,' 

 vol ii, 1883. 



51. Wilson, E. B.— *The Cell in Development and Inheritance,' The 



Macmillan Company, New York, 1896. 



52. ZiMMEEMANN, K. W.— " Studien iiber Pigmeutzellen, etc./' 'Archivf. 



micros. Anat.,' Bd. xli, 1893. 



EXPLANATION OF PLATES 9—11, 



Illustrating Mr. Chas. B. Wilson's paper on ''The Habits 

 and Early Development of Cerebratulus lacteus 

 (Verrill)/' 



Key to Letters. 



am. Apical muscle, ani. Anterior invagiuation. bv. Blood-vessel, c. 

 Intestinal caeca, cc. Cilia cells, cm. Circular muscles, com. Circumoral 

 muscle, ct. Connective tissue, dvm. Dorso-ventral muscles, ec. Ectoderm. 

 en. Entoderm, gc. Gelatine cell. glc. Gland-cell. ^r. Groove for food. im. 

 Interparietal muscle, lam. Lappet muscles, hi. Longitudinal muscles. 

 lom. Locomotor muscles, o. Ovary, ce. (Esophagus, pm. Post-oesophageal 

 muscle, s. Stomach, sc. Sperm mother- cell. t. Testis, wc. Wall-cell. 

 yc. Yolk-cell. 



PLATE 9. 



Fig. 1. — Cerebratulus swallowing a Nereis five minutes after dismembering 

 the posterior half of its body. Photograph from preserved specimen, one 

 eighth life size. 



Fig. 2. — Cerebratulus with regenerating papilla. Photograph from life, 

 one eighth life size. 



