A MKMOlIv UPON THE (JENUS 
I- .. <lw. .ronim Limnohyops, the skeleton ol‘ wliichiias l>een so little 
jl,-teniniiat.oiis u>>' ‘ r ' ^ .something to the morphology of this 
I*""" M 1 , nv i,l<.nlWioa,i,.„. will, I tl.ink, atan,!. Tl.crc. ia no.doal,, 
.un.'..r.l,c. .vi. »,aa.k.a. 1 .ofer t„ tl,e line akelcton «f Pal.o.yops 
paludosus, with ti-.-th. fonn.l in the Prineeton Collection. . 
With sneh limitations it is clearly impossible to write a final memoir upon tins 
p-n.iH Mv ol.ji-et has In-en rather to break the way, to clear up the synonyms, to 
,listingui.«h'tl.e'.lifreivnt tyiies. and to throw as niiich light as possible upon the mor- 
phologv and the variations in dental and skeletal structure. 
'I’i.e ivmler will find the phylogenetic part of this work rather crude. Owing 
to the pivsmit lack of material, I am unable to fill in the gap.s, and offer the scheme 
at till* eml of this memoir as a preliminary basis for further observations. 
It is with the givatest .satisfaction and pleasure that 1 take this opportunity to 
tliaiik mv friend Dr. Henry K. Osborn, now of Columbia College, who, upon my re- 
turn fnaii Ceniiaiiy in the fall of 1889, invited me to come to Princeton, and sug- 
gest«*d lay taking iip this investigation. His kindly advice and many valuable sug- 
g«>stions iiavi- Isam a constant stimulus to me throughout the course of my work. 
I am also imlebted to I’rof. Scott for having given me the aid of his valuable criti- 
«-isni in many cas<-s. .Mr. Hndolph Weber has prepared the drawings for this 
memoir, and thev an* np to his usual fine standard of Avork. In conclusion 1 Avisli 
to thank Dr. Edw. .1, Nolan of the Academy of Natural Sciences of Philadelphia fiir 
tlie tnadde he has taken in connection with this memoir. 
IXTHODI'CTION. 
Prei’ious Lileralure. — 'I'Ik* literature on the sul>family Falceosyopince is very 
limited, comparatively few authors having Avorked upon this group of fossil animals. 
.\inong tin- .Vineriean palannitologists Avho IniA'e AA'orked upon Palceosyops, Ave must 
first mention Piufessor la'idy. He states in the preface to his Avork ” The Ex- 
tinct \ ertebnite Eannaofthe M'estern Territories,” that his time had been so much 
taken up with pn)ft>s.siomd engagements, that he had not been able to study the 
material descrilM'd In the alsiAe mentioned AAork as thoroughly as it should IniAe been, 
ami conchule.s that the msnlts aiv not as complete as he aa ouIiI like to IniA e had them. 
I find on candidly studying his original material and comjiaring the same Avitli 
Ills de.s4-riptions. that then* is .some confusion in his Avork, and a number of slips in 
n'ganl to th<' s|H‘cific ndations of the forms described. 
Nomenclnhire and Synonyms . — In my preliminary paper I attem])ted to clear up 
the iiomenclatnn* and the s|H'cific relations of the sjAecies included in this subfamily', 
and I shall include this jKirtioii of my former paper in this for reference. 
< o|H>, in his “ I ertiary \ ertebrata,” has shoAvn the relation of the nomenclature of 
PaJteosyops and Limnohyus proposed by Marsh and Leidy, and there is no question 
as to I/cidy s priority. Eeidy de.scribed the genus Palceosyops three months before 
ars I pn »Iisln*d his iindiminary notice, in Avhich he describes his Palceosyops laticeps. 
