ON PTYOHODERA FLAVA. 169 



Anal Respiration. 



I should like to direct the attention of those zoologists who 

 may have future opportunities of observing living Balano- 

 glossus, to the possibility of the occurrence of anal respiration. 

 When the posterior end of the body is protruding from a mass 

 of sand and seaweed I have observed the anal orifice in P. 

 flava to open periodically^ widely, and slowly for a second or 

 two, and then to close up again. This may occur two or three 

 times to the minute, and it has apparently no relation whatever 

 to the evacuation of feeces. 



In the case of the large Balanoglossus occurring at the 

 Islands of Bimini, in the Bahamas (species not stated), whose 

 development was studied through theTornaria stage by Morgan,^ 

 the author states that generally the posterior end of the worm 

 protrudes from the surface of the sand, sometimes as much as 

 an inch. " If," he says, " the spade is thrust rapidly into the 

 sand before the worm has been disturbed, it is easy to cut off 

 from six inches to a foot of the hind end of the body, but im- 

 possible to get more of the worm.^' When it is so deeply em- 

 bedded in the sand, it is conceivable that the branchial respira- 

 tion would not entirely suffice for the needs of the animal, and 

 that anal respiration may occur as an accessory to the former. 



With regard to the tenacity of life exhibited by P. flava, 

 it cannot compete with Balanoglossus Kowalevskii in this 

 respect, according to Bateson's account (quoted by Spengel, 

 loc. cit., p. 341). In a dish of P. flava, in which the water 

 became slightly turbid overnight, the Ptychodera were nearly 

 all dead, those that were not dead being moribund, and they 

 were outlived by several Annelids. 



Genital Pleurse. 

 The genus Ptychodera is distinguished from the other genera 

 of Enteropneusta, established by Spengel, — above all by the 

 possession in the anterior region of the body (the branchio- 



' T. H. Morgan, "The Development of Balanoglossus," * Journ. Morph.,' 

 vol. ix, 189i. 



