980 



SCIENCE. 



[N. S. Vol. XVII. No. 442. 



the superior facilities for land and fresh-water 

 work offered by Jamaica are a far more than 

 compensating advantage. 



Finally, I should like to emphasize the very 

 great advantage which would come to the labo- 

 ratory from being located in the midst of such 

 a hospitable community as is to be found in 

 Jamaica. This is a point upon which Dr. 

 Duerden would naturally not care to enlarge, 

 as he was himself for four years a leader in 

 extending courtesies and favors to visiting 

 scientists. The government officials and the 

 officials of the fruit company, which virtually 

 controls communication with the United 

 States, are simply unwearying in their efforts 

 to put the visiting scientist under lasting 

 obligations, and if Jamaica were selected as 

 the site of the proposed laboratory, there is 

 ■ nothing the people there would not do to make 

 the establishment a success, and to convince 

 all comers that there is no place like Jamaica. 

 Hubert Lyman Clark. 

 Olivet College, 



June, 1903. 



SHORTER ARTICLES. 



ON THE STRUCTURE OP THE PLESIOSAURIAN SKULL. 



An excellent example of a plesiosaurian 

 skull, recently kindly entrusted to me for 

 study by the authorities of the National Mu- 

 seum, confirms so well the rather remarkable 

 determinations of the frontal elements re- 

 cently published by me, that I desire to make 

 a brief mention of the matter in Science, in 

 anticipation of a more complete description, 

 which may be delayed a year or two. The 

 specimen is from the Eagle Ford Shales, from 

 the vicinity of Austin, Texas, and is, I have 

 little or no doubt, both generically and speci- 

 fically identical with the type of Brachauch- 

 eniiis liicasi, recently described by me from 

 the Cretaceous of Kansas. The specimen lies 

 with its dorsal surface exposed, beautifully 

 supplementing the type specimen of the 

 species now exliibited in the National Mu- 

 seum. 



I have no longer any doubt that the so- 

 called frontal bone in all plesiosaurs is in 

 reality a rostral prolongation of the parietal 

 bone, extending forward to meet the pre- 



maxilla, and completely excluding the frontals 

 from union in the median line. There is no 

 supraorbital bone, and the so-called postorbital 

 is really the postfrontal, or postfronto-orbital. 

 The nasal has never yet been certainly found 

 as a distinct ossification, but the lachrymal ex- 

 ists as a distinct bone, though often fused with 

 the maxilla. 



The study of this specimen confirms my 

 belief that the genus is closely related to 

 PUosaurus of Europe, from which it is dis- 

 tinguished by the entire absence of doiible- 

 headed cervical ribs. I am, furthermore, con- 

 vinced that the genus belongs to a family 

 distinct from the true plesiosaurs, and I 

 believe that this family is the Pliosauridse, 

 hitherto rejected by most students of the 

 order. Whether all the characters given be- 

 low will apply to the European forms I do 

 not know, since the palatines are thought to 

 be separated in PUosaurus, and others may 

 occur in true plesiosaurians. I would, how- 

 ever, define the family as follows : 



Pliosauridse: Skull depressed; no parietal 

 crest; palatines broadly contiguous in the 

 middle line; pterygoids with a prominent 

 ridge and abutting mandibular process. Neck 

 short; cervical ribs single or double headed; 

 all vertebrae without infracentral vascular 

 foramina. S. W. Williston. 



the reactions of PARAMCECIA AND OTHER PRO- 

 TOZOA TO CHEMICAL AND ELECTRICAL STIMULI. 



The recent work of Mathews * on the na- 

 ture of the chemical stimulation of the motor 

 nerve, and that of E. S. Lillie f on the reac- 

 tion of nuclear and cytoplasmic structures to 

 the electric current, have greatly strengthened 

 the theory that protoplasm, at least in some 

 of its forms, consists of a colloidal solution 

 whose particles may be either positively or 

 negatively charged. 



The present paper is a brief iDreliminary 

 account of some exj^eriments on the reactions 

 of Paramwcia and other protozoa to chemical 

 and electrical stimuli, and the visible changes 



*Mathews, Science, XV., 1902, p. 492, and 

 XVII., 1903, p. 729. 



t Lillie, American Journal of Physiology, VIII., 

 1903, p. 273. 



