Apkil 30, 1909] 



SCIENCE 



715 



this is the fact, for a number of reptilian char- 

 acters are present. 



The notochord, near the middle of its passage 

 through the skull, dips beneath the basal plate 

 and is connected with the dorsal wall of the 

 pharynx in two places. The cartilages which will 

 later form the ear-bones are of the type common 

 to the mammals at this stage of development. 

 A foramen nervus abducens is present. It is in 

 the same position as the similarly named foramen 

 in the reptiles, but the two are not homologous, 

 that in Sus being secondary. The cranial cavities 

 in the reptiles and mammals are not strictly 

 homologous, bui the cavity in the mammals is 

 larger morphologically than that of the reptiles 

 and has been increased by the addition of the 

 reptilian cavum epiptericum. Vestiges of the 

 primitive side wall of the cranium are found in 

 Sus. Taken as a whole, the chondrocranium of 

 the pig is that of a generalized mammalian type. 

 It shows certain specialized characters such as the 

 narrowed anterior portion of the basal plate, the 

 large size of the ear capsules, and the secondary 

 foramen nervus abducens, but these are less 

 striking than the secondary characters of Echidna, 

 Talpa, Lepus or the Primates. 

 Placentation of an Armadillo: H. H. Laiste, State 



University of Oklahoma. 



The placentation of the Edentates has not been 

 thoroughly studied and only a few observations 

 have been recorded. A female nine-banded arma- 

 dillo (Tatu novemoinotum) in captivity gave 

 birth to four young' and an examination of the 

 deciduate placenta revealed some novel features. 

 There was a complete fusion of the four chorionic 

 vesicles into one. The^ four amnia were united 

 so as to divide the chorionic cavity into four 

 longitudinal chambers, each with a single um- 

 bilical cord attached to its wall. In this specimen 

 the placenta is intermediate in form between the 

 zonary and the discoidal. The villi are present 

 in a broad band surrounding the chorionic vesicle, 

 which is barrel-shaped and has thin membranous 

 ends devoid of villi. The villous band is made up 

 of two disc-shaped areas of very long villi, sepa- 

 rated by two bands of very short villi. Each of 

 the two areas with long villi has on its amniotic 

 surface the points of attachment of two umbilical 

 cords. There is no indication of a decidua cap- 

 sularis. This highly developed placenta would 

 indicate that the armadillo is a specialized form, 

 instead of a primitive type; and if this character 

 is of systematic value, the Edentata are to be 

 regarded as a heterogeneous group and not a 

 natural one. 



Cestodes in Flesh of Marine Fishes: Edwin Lin- 

 ton, Washington and Jefferson College. 

 The only common food iishes found to harbor 

 cestodes habitually in the ilesh are the butterfish 

 (Rhombus triacanthus) and the harvest fish {R. 

 paru). The cestode is Otobothrium cr&naoolle. 

 The adult stage has been found in the hammer- 

 head shark (Sphyrna zygmna) in New England 

 waters, in the sharp-nosed shark (Scoliodon terrcB- 

 novce) at Beaufort, and in the cub shark {Car- 

 eharhinus platyodon) at Tortugas. 



In the encysted stage it has been found in 

 twelve species of Woods Hole fishes, in thirteen 

 species of Beaufort fishes and in three species of 

 Bermuda fishes. In all these, with the exception 

 of the butterfish and harvest fish, the parasites 

 were confined to the body cavity where they were 

 encysted on the viscera or in the walls of the 

 stomach and intestine. In the summer of 1908, 

 butterfish to the number of 715 were examined 

 and cysts were foimd in all but 22. Twelve har- 

 vest fish were examined and numerous cysts were 

 found in each. The paper discusses the excep- 

 tional position of these cysts in the butterfish and 

 the unusually high percentage of affected fish. 

 Systematic Relations of the XJrodela- as Inter- 

 preted by a Study of the Soxmd-transmitting 

 Organs: H. D. Reed, Ithaca, N. Y. 

 This study is the result of the curiosity aroused 

 by the apparent conflicting statements regarding 

 the systematic position and relationships of the 

 various groups of Urodela. Believing that the 

 limits and position of some of the larger groups 

 have been based upon structures which are either 

 affected by environment or negative in their char- 

 acter, and, furthermore, believing that the classi- 

 fication of any group is sounder when based upon 

 results gained from a comparative study of several 

 organs or systems, it was decided to place in 

 evidence a comparative study of the sound-trans- 

 mitting organs already under investigation with 

 another, end in view. 



Cryptobranchus is the most generalized.- The 

 Ambystomidse are intermediate between Crypto- 

 branchus and all other groups. The Plethodon- 

 tidse and Desmognathidae are departures from the 

 Ambystoma stem while from these the Sirenidse 

 and Am,phiuma seem to be degenerated. Diemio- 

 tylus and Triton are identical with regard to 

 these ear structures and differ from all others. 

 They are to be considered the most specialized. 

 Between Diemictylus and Triton on the one hand 

 and the Ambystomidae on the other Salamandra 

 stands intermediate, resembling more strongly the 

 Ambystomidse. 



