596 



COMPARATIVE ANATOMY 



CHAP. 



A. F. Marion. Etudes zoologiques sur deux especes d'Enteropneustes. Arch. Zool. 



gner. et exper. (2). Tome IV. 1886. 

 E. Metschnikoff. Untersuchungen uber die Metamorphose cinigcr Secthiere. 1. 



Ucbcr Tornaria. Zeitschr. f. wiss. Zool. 20 Bd. 1870. 

 T.H.Morgan. Grou-th and metamorphosis of Tornaria. Journ. Morph. V. 1892. 



The Development of Balanoglossus. Journ. Morph. Vol. IX. 1894. 



Job. Miiller. Ucbcr die Larvcn und die Metamorphose dcr Eehinodcrmtn. Part 2. 



Akad. d. Wissensch. 1848. Berlin, 1850. 

 Wladimir Schimkewitsch. The Fauna of the White Sea : Balanoglossus Mcresch- 



korskii Wagner. St. Petersburg, 1889. (In Russian.) 

 J. W. Spengel. Die Enteropneusten. Fauna and Flora des Golfes von Neapcl. 



18 Monoyraphic. Berlin, 1893. The most important recent work. 

 W. F. R. Weldon. Preliminary note on a Balanoglossus larva from the Bahamas. 



Proceed. Roy. Soc. London. Vol. XLII. 1887. 

 R. v. Willemoes-Suhm. Biologische Beobachtungcn uber niedere Meeresthiere. 4. 



Ucbcr Balanoylossus Kupfferi aus dem Oeresund. Zeitschr. f. wissensch. Zool. 



21 Bd. 1871. 

 A. Willey. Amphioxus and the ancestry of the Vertebrates. 1894. 



Appendage to the Enteropneusta. 



Cephalodiseus and Rhabdopleura. 

 I. Cephalodiseus (Figs. 469-471). 



The body is about 1 mm. long, almost bean-shaped, bilaterally 



symmetrical ; it is rounded 

 posteriorly and anteriorly 

 flat, with a slight backward 

 slope. The most important 

 organs which can be distin- 

 guished externally are found 

 in this anterior sloping sur- 

 face, while in the whole of 

 the rest of the body only 

 one organ appears, viz. a 

 cylindrical stalk or pedicle, 

 which rises from the ventral 

 side of the rounded posterior 

 end of the body. 



In that part of the body 

 which projects most anteri- 

 orly, i.e. the anterior end 

 of the dorsal side, lies the 

 anus, while somewhat be- 

 FIO. 4titi. Cephalodiseus dodecaiophus, from the hind the anterior end of 



ventral side (after M'Intosh). 1, Tentacles ; 2, buccal t h e ven tral side, the HlOUth, 



shield = proboscis ; 3, mouth ; 4, buds ; 5, pedicle ; 6, trunk. 



and between 

 slope mentioned above, the inter -stomatal region. 



the two the 

 The median 



