942 



SCIENCE 



[N. S. Vol. XXVII. No. 703 



A Litter of Short-tailed Dogs: R. M. 



Steong, The University of Chicago. 



A fox-terrier bitch gave birth on October 

 31, 1907, to five pups — four males and one 

 female. One of the males had practically 

 no tail, and the other pups had short tails 

 of various lengths. The tails were meas- 

 ured on November 28, as follows: The 

 female and one male had tails measuring 

 about 1^ inches. A third male had a tail 

 2^ inches long, and the fourth male's tail 

 measured 4 inches. The female and the 

 tailless male are being reared for breeding 

 studies. The mother's tail is short, and it 

 has the appearance of having been cut at 

 some time. The male parent is unknown, 

 and the condition of the mother's tail at 

 birth has not yet been satisfactorily de- 

 termined. 



Some Stages in the Embryology of certm?i 

 Degenerate Phoridce and the supposedly 

 Hermaphroditic Genus Termitoxenia : 

 Chaeles T. Brues, Public Museum, 

 Milwaukee, Wisconsin. 

 The family Phoridse form an interesting 

 group of Diptera on account of a number 

 of genera which are partially or wholly 

 wingless in the female sex, and very de- 

 generate in other respects. 



The oogenesis of a species of the Texan 

 myrmecophilous genus Ecitomyia was 

 studied and compared with that of Termi- 

 toxenia, another form of aberrant Phoridre 

 which has been investigated by Wasmann. 

 The resemblance is very close and serves 

 to confirm the writer's opinion of the close 

 relationship between Termitoxenia and 

 other Phoridxe. 



The gross features of the embryology of 

 Termitoxenia were studied and found to 

 present no remarkable divergence from the 

 same stages in some other Diptera. They 

 do not confirm the supposition of Was- 

 mann that these insects give birth to the 

 imago stage with a suppression of the larva 



and pupa, since the oldest embryos found 

 are no farther advanced than those of 

 certain viviparous flies like Sarcophaga, 

 which give birth to living larvae. 



The writer could find no evidence in sup- 

 port of the hypothesis that these animals 

 are hermaphroditic. 



Suggestions for a Natural Classification of 

 the Family Lymnmdce: Frank Collins 

 Baker, Chicago Academy of Sciences. 

 The fresh-water pulmonates have been 

 gradually undergoing the splitting process 

 so notably carried out in the land snails 

 by Pilsbry, Dall and others. The family 

 Lymnffiidffi contained, until recently, the 

 genera Lymncea, Planoriis, Physa and 

 Ancylus, besides several other small genera. 

 Ancylus and Physa have been separated, 

 forming the families Ancylidse and Phy- 

 sidse, each characterized by peculiarities 

 of shell, radula and genitalia. Of the old 

 Lymnffiidffi there still remain Lymncea and 

 Planoriis, each falling into a sub-family. 

 A study of these two groups seems to point 

 inevitably to their separation into two 

 families, Lymnjeidfe and Planorbidse, the 

 former having a long-spired shell, a uni- 

 cuspid central tooth, bi- or tri-cuspid lateral 

 teeth, and the male genitalia with strong 

 muscles protracting and retracting the 

 male organ, which forms a distinct penis 

 and penis sac. In Planorbidas the shell is 

 discoidal, the central tooth is bicuspid, the 

 laterals are tricuspid, with a modified 

 mesocome in the typical genus, and the 

 male organ is destitute of the strong 

 muscles of Lymncea and is not strongly 

 diflierentiated into penis and penis sac. In 

 Planoriis the tentacles are long and fili- 

 form while in Lymncea they are flat and 

 triangtilar.^ 



As thus restricted, the LymuEeids pre- 

 sent a homogeneous group of snails which 

 may be divided into several genera and 

 ' Pompliolaginae -will probably also be found to 

 rank as a family. 



