BIOLOGY. 291 



THE EARLY STAGES OF BRACHIOPODS. BY EDWARD S. MORSE. 



The writer made a visit to Eastport, Me., early in the summer, 

 for the purpose of discovering the early stages of a species of 

 brachiopod {Terebratulina sepientrionalis, Couth.) so abundant in 

 those waters. As little has been known regarding the early stages 

 of this class of animals, the focts here presented will be of inter- 

 est, as settling beyond a doubt their intimate relations with the 

 Polyzoa. In a few individuals, the ovaries were found partially 

 filled with eggs. The eggs were kidney-shaped, and resembled 

 the statoblasts of Fredericella. No intermediate stages were seen 

 between the eggs and a form which recalled in general propor- 

 tions Megerlia or Argiope, in being transversely oval, in having 

 the hinge-margin wide and. straight, and in the large foramen. 

 Between this stage and the next, the shell elongates, until w^e 

 have a form remarkably like Lingula, having, like Lingula, a 

 peduncle longer than the shell, by^ which it holds fast to the rock. 

 It suggests, also, in its movements, the nervously acting Pedi- 

 cellina. 



In this and the several succeeding stages, the mouth points 

 directl}^ backward (forward of authors), or away from the pedun- 

 cular end, and is surrounded b}' a few ciliated cirri, which forcibly 

 recall certain polyzoa. The stomach and intestine form a simple 

 chamber, alternating in their contractions, and foi;^'ing the parti- 

 cles of food from one portion to the other. At this time, also, the 

 brownish appearance of the w^alls of the stomach resemble the 

 hepatic iolds of the Polyzoa. In a more advanced stage, a fold 

 is seen on each side of the stomach ; from this fold, the compli- 

 cated liver of the adult is developed, first, b}'^ a few diverticiflar 

 appendages. 



When the animal is about one-eighth of an inch in length, the 

 lophophore begins to assume the horseshoe-shaped form of Pecti- 

 natella, and other high Polyzoa. The mouth at this stage begins 

 to turn towards the dorsal valve (ventral of authors) ; and, as the 

 central lobes of the lophophore begin to develop, the lateral arms 

 are deflected. In these stages an epistome is very marked ; and 

 .it was noticed that the end of the intestine was held to the mantle 

 by attachment, as in the adult, reminding one of the funiculus in 

 FhyladolcEmata. No trace of an anus was discovered, though 

 many specimens were carefully examined under high powers for 

 this purpose, the intestine of the adult being repeatedly ruptured 

 under the compressor without showing any evidence of an anal 

 aperture. — American Naturalist, Septanber, 1869. 



PRIMORDIAL FAUNA. 



Dr. J. J. Bigsby, in his "Thesaurus Siluricus," remarks, "The 

 primordial stage did not start forth, Pallas-like, at once, in full 

 maturity. The quantity, variety, and high rank of its fauna shut 



