Tin: QEPHYREA. 





is surrounded by u cir< iil;n band <l cilia placed immediately 

 behind the mouth ( W, W)> and resembles a i ueso- 



trochal Annelidan larva. As development advances it loses 



FIG. 56. SI>?MCM/.'/M* (after Keferstein and Ehlers). 1 



I. The animal laid open longitudinally J n. s. 7. tentacle*; r, th fonr retractor 

 muscles of the proboscis : /. tin- points at which tliev were attached to tin- walls 

 of the body; , oesophagus ; /. intestine: (/.ami-: /../. l.mp- of t!i 



<e, y, appendages of the rectum; e, fusifoim miiM-le ; //-. ciliated u'roove on tho 

 inner side of the intestine ; </, anal muscle* ; , cwcal glands; t. caeca which open 

 on each side of the nervous cord, and are generally considered to b 

 pore nt the hinder end of the body; />, nervous COM, \\hich ends in a lol>.-' 

 ^lionic mass, close to the mouth, and presents an enlargement. (/', at its poste- 

 rior end : m, m', m", mnscles associated with the nervons cord?. 



II. A larval Sipunculutf about ^ of an inch lonj;: o, mouth : -. millet : *, caecal 

 rland; i, intestine with masses of fatty cell : ". anus : />. - -i-iati-d -rro-'v.- of the 

 intestine ; g, brain with two pairs of red eye-spots ; n, nervous cord, />, pore; 

 t, t, eo-called testes ; TP, W, circlet of cilia. 



this apparatus, and passes gradually into the adult form. Tn 

 Phoronis, the embryo is also mesotrochal, but it has two 

 ciliated bands, one circular, round th<> anus, and the other im- 

 mediately behind the mouth. The poet-oral hand of ci!i 

 produced into numerous tentaouliform lobes, and fringes the 

 free edge of a broad concave lobe of the dorsal side of the 

 body, which arches over the mouth. In this state the embryo 



Zoologiache Beitrage," 1861. 



10 



