ON THE DEVELOPMENT OF LINGULA ANATINA. 99 



doubtful whether it was really so. If it was an embryo, it was 

 at the 4-cell stage (measuring 220/^x120/^). 



Joubin ('87) remarks that he has repeated and confirmed 

 Moese's observations on Terebratulina at BoscofF, and Kowale- 

 vsky's on Cistella at Banyuls-sur-Mer, but he gives no further 

 account of his studies. 



Beeches, ('91) introduced the term " Protegulum " for the 

 common form of shells at embryonic stages (p. 344). 



The same author ('93) studied three specimens of I'erebratalia 

 obsoleta Dall in dry condition (0.3 mm., 0.65 mm. and 1 mm. 

 in length). 



Ekmann ('96) while studying the sections of an adult Cistella 

 observed a larva with three regions in each of the oviducts. 



SiMROTH ('97) described four free-swimming larvœ, of which 

 two were collected during the Plankton Expedition, and the other 

 two through von Schab. The larvœ referred to as " No. 1 " and 

 " No. 2," are supposed to belong to Distinct or an allied form. 

 " No. 3 " taken from the west coast of Africa, was supposed 

 to be a Lingula larva by Blochmann and Simroth. " No. 4 " 

 is identified by the former as belonging to Orania ('98, p. 426). 

 Blochmann ('98) investigated the anatomical structure of 

 the larvœ of Discinisca collected at Rhio, the capital of the 

 island Bintang, south of Singapore. He studied them from sections 

 as well as in surface view, and added many details to the early 

 observations of Fritz Müller. 



From the above references 1 a table may be compiled giving 

 in systematic arrangement a list of Brachiopods, whose young- 

 forms or early embryonic stages have been studied. 



1. Many papers dealing with the phylogenetic and ontogenetic development of the 

 hard parts of the Brachiopoda have been omitted. 



