April 28, 1905.] 



SCIENCE. 



657 



it is claimed, " occur in certain families of 

 elasmobranchs, and in five families of teleosts, 

 viz., the Blenniidse, the Cyprinodontidte, the 

 Scorpsenidse, the Comephoridae and the Em- 

 biotocidffi" (p. 418). To this list should he 

 especially added the remarkable Zoarcidje and 

 Brotulida? combined in a single family under 

 the name Zoarcidsc in the systematic part of 

 the work (pp. 712, 713). Some fresh-water 



* Scombresocidse ' of the genus ZenarcJiopterus 

 are also viviparous (p. 638). Certain Cyprin- 

 ida? (p. 584), vSiluridffi and Cottidse have also 

 been declared to be viviparous, but the claims 

 have not been quite fully proved. 



VI. 



The Cyclostomata are ranked as a class, and 

 the two principal divisions, called ' Myxino- 

 ides ' and ' Petromyzontes,' are - designated as 

 ' orders.' Why the old names Marsipo- 

 branchii, Hyperotreti, and Hyperoartia should 

 be abandoned is not obvious. The groups, 

 however, are valued in accordance with gen- 

 eral current usage, but the last two are of at 

 least subclass rather than ordinal value. The 

 immense gap Ijetween the ' Myxinoides ' and 



* Petromyzontes ' is apparently scarcely ap- 

 preciated by most naturalists, but it was rec- 

 ognized by Ray Lankester a generation ago 

 (1877) in his distinction of the two groups as 

 classes. The differences are fundamental and 

 affect all parts and organs. If, for example, 

 Professor Bridge had presented a figure of the 

 auditory organs of Petromyzon to compare 

 with those of Myxine and other types (p. 388), 

 the contrast could not fail to strike the ob- 

 server with the requisite knowledge of com- 

 parative anatomy to judge of the facts. 



The ' Myxinoides ' are divided into two 

 families — ' Myxinidse ' and ' Bdellostomatidse.' 



The ' Petromyzontes ' are aggregated in a 

 single family, as usual called ' Petromyzont- 

 idffi.' (It should be Petromyzonidae.) Pro- 

 fessor Bridge evidently had an imperfect 

 knowledge of the species. He mentions (p. 

 426) Petromyzon with ' three species widely 

 distributed in Europe,' and just afterwards 

 states that ' Ich tliyomyzon, Bathymyzon, 

 Entersphenus [— Entosphenusi and Lampetra 

 are also northern forms.' Lampetra was orig- 



inally distinguished for two of the ' three 

 species widely distributed in Europe.' The 

 genera mentioned fall into two primary 

 groups: Petromyzon, Bathymyzon and Ich- 

 tJiyomyzon in one, Lampetra and Entospheniis 

 in the other. 



The statement is made that ' a new genus 

 and species from Chili has been recently de- 

 scribed under the name of Macrophthalmia 

 chilensis.' The supposed new tj'pe was later 

 (1902) shown by its author (L. Plate) to be 

 simply a ^stage (' .Tugendstadium ') in the de- 

 velopment of the Gcotria cJtilen'sis. The 

 Petromyzonids of the southern hemisphere 

 differ remarkably from those of the northern 

 in tlieir development as well as otherwise. 



VII. 



The Elasmobranchii are treated in the old- 

 fashioned style. After the extinct orders 

 Pleuropterygii (p. 436), Ichthyotomi (p. 438) 

 and Acanthodei (p. 440), the now extant types 

 are considered under the orders Plagiostomi 

 (p. 442) and Holocephali (p. 466), and the 

 Plagiostomi are, as of old, divided directly 

 into Selachii and Batoidei (p. 457). Such a 

 division is certainly not expressive of the 

 facts of morphology. There can be no ques- 

 tion that the structural differences between 

 the so-called Notidanida; and Chlamydo- 

 selachidse, on the one hand, and all the other 

 Selachians, are of much more morphological 

 significance than those between the sawfishes 

 of the families Pristiophoridse and Pristidse. 

 The Heterodontidse also appear to be widely 

 differentiated from the others, though not as 

 much so as might be inferred from the old-time 

 allusions to them. In fine, the segregation 

 into (1) Diplospondyli or Opistharthri (Noti- 

 danidae), (2) Prosarthri (Heterodontida;), (3) 

 Tectospondyli (sharks without anal and rays) 

 and (4) Asterospondyli (other living sharks) 

 appears to comport best with structural and 

 developmental facts as well as with the pale- 

 ontological record. 



The name Notidanida; has been used just 

 because it is the term employed by Professor 

 Bridge, but it should be discarded. Professor 

 Bridge, apparently, is content to take a name 

 as he finds it without caring whether it is 



