246 ZOOLOGICAL RESEARCHES 



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a. Land- and freshwater Mollusks. 



1. Vaginula pleuroprocta v. Marts. — A few specimens 

 from Schieffelinsville. 



2. Streptaxis Monroviana Rang. — One specimen , with- 

 out exact locality and probably collected by Mr. Bütti- 

 kofer, belongs to the form figured in Pfeififer's Novitates 

 Conchologicae , PI. 142, fig. 5; a few others, collected by 

 Mr. Stampfli, belong to the same variety and to the var. 

 rimata Pfr. Several young specimens and an adult one 

 of the var. Reduziana Petit , are found by Büttikofer at 

 Schieffelinsville. 



I have availed myself of this opportunity, to examine 

 the radula of a young specimen of this species. The juve- 

 nile state was ranged by Rang in the genus Helix (Ann. 

 des Sciences nat. 1831) till Pfeiffer in his Monographia 

 Heliceorum , III, p. 81, and Prof, von Martens (Malak. 

 Blatter, 1866, p. 104) supposed it to be the young of 

 Streptaxis nohilis Gray = Monroviana Rang. Dr. Dohrn , 

 after a comparison of a great number of specimens , came 

 to the same conclusion (Malak. Blatter, 1866, p. 136), 

 the correctness of which has been fully confirmed by the 

 examination of the radula. 



The length of the radula of a snail removed from a 

 shell which measures 12 mm. in its greatest diameter, is 

 about 14 mm., the breadth is scarcely 2 mm. The nume- 

 rous teeth converge towards the median line at a rather 

 acute angle. The number of transverse rows of teeth or 

 spines goes from 65 to 70 , the longitudinal rows amount 

 to about 57 on each side , and consequently a transverse 

 row is composed of about 115 rows. It is however diffi- 

 cult to ascertain the precise number of teeth , especially 

 in consequence of the many small particles of food which 

 adhere to the teeth and which can only partially be re- 

 moved by repeated washings. The teeth are simple and 

 ensiform ; the central ones are the longest and they de- 

 crease in length towards the margin of the radula. The dis- 



Notes Trora tlie Leyden IVIuseuxii , "Vol» X. 



