70 GONKLIN — EMBRYOLOGY OF A BRACHIOPOD. [April 4, 



more particularly with the position of Heider, as to the affinities of 

 the brachiopods. The relationship between Phoronis, Bryozoa 

 and Brachiopoda seems to me sufficiently close to justify the placing 

 of them in the same phylum, though not in the same class, as Lang 

 has done. 



Postscript. 



Since this paper was written I have seen Ideka's (1901) very 

 important contribution on the '* Development, Structure and Meta- 

 morphosis of Actinotrocha." Ideka's work is in all respects the 

 most thorough and extensive which has yet been done on the devel- 

 opment of Actinotrocha, and in many very important points he 

 differs decidedly from Masterman. Some of the differences be- 

 tween Actinotrocha and the brachiopod larva, which are pointed 

 out on p. 65, disappear in the light of this work. For example, 

 Ideka finds that there is but one complete septum in the body, that 

 between the collar and the trunk, while the cavities of the preoral 

 lobe and collar are in communication through a very incomplete sep- 

 tum. Furthermore Ideka finds no trace of a second pair of neph- 

 ridia or of a ** proboscis pore," such as Masterman described, 

 while the two '* chorda" diverticula of Masterman (Diplochorda) 

 are represented by a single unpaired diverticulum in the Japanese 

 species. Whether this is a glandular or skeletal structure is left an 

 open question. 



With the exception then of the single septum between the collar 

 and the trunk regions there are no important differences between 

 Actinotrocha and the brachiopod larva. This septum occupies a 

 position in Actinotrocha corresponding to the posterior mantle 

 furrow of the brachiopod larva, and it would be interesting to 

 know whether, in stages of the brachiopod larva later than those 

 which I have studied, any trace of a septum can be found in this 

 position. 



Literature List. 



Beech ER, C. E. ('91). Development of the Brachiopoda. Am Jour. Set. 



Vol. 41. 

 Beecher, C. E. ('92). Development of the Brachiopoda. Am. Jour. Sci., 



Vol. 44. 

 Beechkr, C. E. ('93). The Development of Terebratulina obsoleta. Trans. 



Conn^ Acad., Vol. 9. 

 Blochmann, F. ('92 and 1900). Untersuchungen ilber dm Ban der Brachio' 



poden. Jena. 



