294 RECORD OF SCIENCE FOR 1887 AND 1888 



iiew genus as near that of the genus Helojjora \n the fatiiily Arthro- 

 stylidiv (Ulrich). This family name is based upon tlie new generic name 

 Arthrostylus, which, iu a foot-note, the author erects in pUice oii Arthro- 

 nema, Ulrich, which he finds preoccupied. Illustrations are given of 

 the internal characters of Helopora, also of the characters of the family 

 to which it belongs. 



James Hall (93), at the end of the forty -first report of the Trustees of 

 the New York State Museum of Natural History, published TectuUpora 

 uov. subgen., Fenestella {TectuUpora) looulata, n. sp., and FenesteUa 

 frequens, n sp., pi. ix, f. 12-15. The pages are not numbered, but as 

 bound would be 496 for all but the last, which is 497. On pi. x the 

 figures 14,15 are called in explanation of plate " FenesteUa nexilis, u. 

 sp.", and on pi. xiv^, figures 10-12 are called FenesteUa varia, n. sp." 



Norman Glass (90) has written a paper on the principal modifications 

 of the spirals' iu the fossil Brachiopoda. The author notes the position 

 of the spirals in the shell, comments upon the attachments of the spi- 

 rals to the hinge-plate of the dorsal valve, and on the loop or the con- 

 nection of the spirals with each other in the various genera of spiral- 

 bearing Brachiopoda. 



U. S. Williams (300) discusses the characters of the representatives 

 of the family Strophomeuidie at its first prominent appearance in the 

 Trenton. He analyzes the characters and shows their relationship to 

 each other. The characters which became at a later stage generic dif- 

 ferentia were found iu a plastic state at the first stage. The specific 

 differentia expressed throughout the life history of the family appeared 

 to be more plastic in the early than in the later species. In the later 

 stages of the history of the family the specific characters are more 

 sharply accentuated, but except in this way tliey scarcely exceed iu 

 variety those appearing at the first stage of existence of the family. 



THE GASTEROPODA. 



'Charles E. Keyes has written several papers (137, 138, 139, 140) in 

 regard to Platyceras and its relations to the Crinoids ui)on which it is 

 found attached. In one of the papers (138) four new species of Platy- 

 ceras are described and figured from the Lower Carboniferous beds of 

 Iowa. They are as follows : 



Platyceras capax, p. 241, f. 14, 15. 

 Platyceras ohliqiium, p. 241, f. 12, 13. 

 Platyceras latum, p. 242, f. 10, 11. 

 Platyceras formosum, p. 242, f. 8, 9. 



In the other three papers the author gives an interesting account of 

 the mode of attachmeut of Platyceras to the dome of Crinoids. The asso- 

 ciation of the front part of the shell with the anal opening suggests the 

 probability that the Gasteropod lived upon the excreta of the Crinoid. 

 The attachment appears to have continued long, and probably during 

 the life of the Platyceras^ and this is regarde(^ as sufficient explanation 



