140 



The above facts and demonstrations were illustrated by a 

 series of drawings laid before the Society. 



Dr. Gould presented descriptions of the following species 

 of shells from the Collection of the U. S. Exploring Expe- 

 dition. 



Pleurotoma seminifera. Testa subulato-turrita, fuscescens, 

 filis deorsum crescenlibus cincta: spira anfr. ad 12, juxta sutu- 

 ram carinatis, deinde excavatis, ad medium nodulisobliquis rubris 

 ornatis : aperlura angusta, | long, testse adequans ; cauda brevi ; 

 sinu seque lata ac profunda ; columella rectiuscula ; fauce livido. 



Long. If ; lat. f poll. Hah. . 



Closely allied to P. mierrupta, Lk., but differing from the fig- 

 ures in color, and from the description in having a more deci- 

 dedly excavated girdle in front of the suture, in the greater 

 obliquity of the folds, and in their not reaching to the suture 

 below. 



Mangelia cithara. Testa parva, rhomboideo-fusiformis, cin- 

 erea, costis acutis longitudinalibus 7 instructa, interstitiis conca- 

 vis, subtiliter transversim striatis : spira turrita, anfr. 7 bene dis- 

 cretis, ultimo ovato-triangulari | long. testsB adequante : apertura 

 angusta, labro lato, varicoso, postice rectangulari vix sinuato ; 

 columella concinne rugosa. Long, f ; lat. /g- poll. Hah. Feejee 

 Islands. 



alive Emtiryology before the Lowell Institute, by Louis Agassiz, Professor in the 

 Lawrence Scientific School, Harvard University — 1849. Below are given refer- 

 ences to the more important labors of those who have studied the metamorphoses 

 of Medusae. — Publishing- Committee. 



Dalyell, in the Edinburgh New Philosophical Journal, 1836. 



Dalyell's Rare and Remarkable Animals of Scotland. London, 1847. 



Siebold. Beitrage zur Naturgeschichte der Wirbellosen Thiere, 1839. 



Sars' Fauna Littoralis Nor\'egice. 



Sars. Annates des Sciences Naturelles, Tome XVL 1841, p. 321. (Translated.) 



Loven. Memoires de I'Academie de Stockholm, translated into Archives de 

 Wiegmann, 1837, p. 249. 



Nordmann. Comptes Rendus, de I'Academie dcs Sciences. 1839, 



Van Beneden. Memoire sur les Campanulaires, 1843 ; and Recherches sur le 

 embryologie des Tubulaires, 1844. 



Du Jardin. Sur la Developpement des Meduses et des Polypes Hydraires. 

 Annales des Sciences Naturelles, Tome IV. p. 257. 1845. 



Agassiz. Twelve Lectures on Comparative Embryology, delivered before the 

 Lowell Institute, December and January 1848- 1849, p. 36 et seq. 



Forbes' Medusse of Great Britain. 



