THE NAUTILUS. 129 



printed many of his papers toward the end of the 18th century, 

 1 recently came on a little paper by Martin Vahl on a new spe- 

 cies of Patella. Vahl was a Danish Naturalist who wrote chiefly 

 on vertebrates, and after whom Morch named the Greenland 

 species of Lymncea. 



It is probable that he was also interested in botany, as he 

 relates that he found his Patella (in the Linnean sense) on the 

 blades of a species of the genus Aponogeton from the East Indies. 

 He states that of the Linnean species of Patella, it is nearest to 

 P. fornicata and porcellana (both now placed in the genus Crep- 

 idula). 



His shell was of about the size of a grain of wheat, horny, 

 fragile, smooth, with a reticulation of brown lines ; the apex 

 short, blunt, basal and somewhat incurved ; the base with a 

 transverse horizontal lip less than a quarter of the basal length. 

 The station of the shell in fresh waters on the blades of Apono- 

 geton in the East Indies. The shell is not figured, but it seems 

 certain that nothing but a species of the group called Gundlachia 

 can correspond to this description, read in 1796, and published 

 in 1798, in the fourth volume of the Skrivter, part 2, pp. 153-5. 

 He called the species Patella aponogetonis. It was not until 

 1849 that Pfeiffer proposed the name Gundlachia for a Cuban 

 species. 



STUDIES IN NAJADES. 



BY A. E. ORTMANN. 



( Continued from page 69. ) 



CARUNCULINA PARVA (Barnes). (See Ortmann, 1912, p. 338.) 

 I received a number of specimens from Arkansas through 

 H. E. Wheeler. Gravid females, with glochidia, were collected 

 in the Ouachita River, Arkadelphia, Clark County, on May 19 

 and June 23, 1911. Among many specimens collected in Saline 

 River, Benton, Saline County, on July 13, 1911, no gravid 



