ANATOMY OF ACHATINELLID^. 59 



The embryo usually attains about 3!/2 whorls before birth. 

 Its shell is perforate, with the columella callused and ob- 

 liquely truncate, or with a convex columellar lobe. The colu- 

 mellar lamella appears later. In Partulina the shell is finely 

 engraved spirally, in Achatinella either more minutely en- 

 graved or smooth. 



Free muscles. The retractor penis attaches distally to the 

 lung floor (not to the uterus as stated by Mr. Binney). The 

 retractor muscles of the tentacles are free from the tail re- 

 tractor or columellar muscle. Both divide anteriorly into 

 three branches, ocular, tentacular and anterior pedal. One 

 of the ocular bands passes between male and female branches 

 of the genitalia. The pharyngeal retractor unites with one 

 of the tentacular bands at about the posterior fourth of the 

 latter. It is deeply bifurcate anteriorly (pi. 20, fig. 4, Par- 

 tulina dolei). 



On account of the uniformity of the soft anatomy in Acha- 

 tinellida:, no special descriptions are given under the generic 

 heads. Characters in the soft parts to distinguish Neivcombia, 

 Partulina, Achatinella or any of the subordinate groups from 

 one another, have not been found. 



The first Achatinella to be dissected was A. bulimoides. The 

 radula was described and the teeth figured by Heynemann in 

 Malakozoologische Blatter, XIV, 1867, p. 149, pi. 1, figs. 2, 2a. 

 Dr. Heynemann remarks on the astonishing similarity of the 

 teeth to those of Janella (Athoracophorus). 



In 1873, Mr. W. G. Binney dissected a considerable num- 

 ber of species, including the groups Achatinella, Bulimella, 

 Achatinellastrum, Partulina, Amastra, Laminella, Leptacha- 

 tina, figuring the teeth of several species and the genitalia of 

 A. producta. (Annals of the Lyceum of Natural History of 

 N. Y., X, pi. 15.) In Annals of the N. Y. Acad. Sciences, iii, 

 p. 96, pi. 3, 6, and 16, 1884, Mr. Binney reviewed his work, 

 figuring the teeth of ten species, including Carelia, and the 

 jaws of Carelia, Amastra and Laminella. 



In 1877 (Jahrbiicher d. d. Malak. Gesellschaft, p. 330), Dr. 

 G. Pfeffer gave an excellent account of the soft anatomy of 

 A. vulpina. He corrected various errors in Binney 's work, 



