106 KDWIN S. GOODRICH. 



sinus it leads by a chink or fissure between tlie gut wall and 

 that of the two collar cavities along the dorsal wall of the 

 oesophagus to the hind extremity of the collar region. Here 

 it falls into the large dorsal vessel with contractile walls." 

 The anterior septum : a '' well-marked mesentery " separating 

 the " collar cavity " from the cavity of the pre-oral lobe. A 

 dorsal mesenter}^ and a dorsal vessel in the " collar " region. 

 The termination of the nephridia by ''broad funnels/' which, 

 " without doubt, open into the collar cavities." Masterman's 

 successors have already dealt severely Avith these contribu- 

 tions to our knowledge of the anatomy of Actinotrocha. 



Ikeda (9) is "much inclined to regard the 'neuropore' of 

 Masterman not as a really existing structure, but as an arte- 

 fact." De Selys Longchamps is also unable to discover evi- 

 dence of its existence (16), and Menon can only find a 

 depression lying ''in the actual ganglion" (13). My obser- 

 vations strongly uphold the opinion of Ikeda. Artificial 

 " sac-like " depressions I have frequently found in front of 

 the ganglion in specimens in which the pre-oral lobe had been 

 turned upwards during fixation by the reagents. The gan- 

 glion is bilobed dorsall3^, and between the two hinder 

 diverging lobes may be generally noticed a very slight de- 

 pression surrounded by elongated cells from which spi-ing a 

 tuft of very long cilia. This slight pitting, which may or 

 may not be artificial, is comparable to the similar flattening 

 or depressing of the surface seen in the apical region of 

 trochosphere larvae. 



The existence of a " subneural gland " has been denied by 

 Ikeda (9). Menon and de Selys Longchamps (13 and 16) 

 describe slight depressions above the mouth. My own 

 observations entirely confirm the opinion of Ikeda that this 

 folding of the oesophageal wall is mainly a product of the 

 fixing method. 



The stomach of Actinotrocha bulges forwards below the 

 narrow oesophagus so as to give rise to a ventral diverticulum. 

 In some species, such as Actinotrocha branchiata, this 

 diverticulum bifurcates in front so as to project on either 



