172 



SCIENCE. 



[Vol. I., No. 13. 



some new facts. He finds, that, on stimulation of 

 the central end of the superior laryngeal nerve in 

 the rabbit, every resulting swallowing movement is 

 accompanied by more or less marked inspiration and 

 expiration, and that the respiratory muscle concerned 

 is the diaphragm. He concludes that the two centres 

 are so united by commissural fibres that every stimu- 

 lation of the deglutition centre is associated with 

 excitation of the respiratory. — (Vii Bols' archiv, 

 1883,57.) H. N. M. [796 



Digestion with exclusion of the stomach. — 

 Working on dogs, Ogata finds, that when food is 

 directly placed in the duodenum, and all gastric (also 

 salivary) secretion is kept out of the intestines, tlie 

 animal can still digest many things well, so as to 

 maintain its weight, and pass normal faeces. Certain 

 foods, however (as connective tissl^e), need the pre- 

 paratory action of the gastric acid in order that they 

 may undergo normal digestion; others need a change 

 in their surface, or decomposition into small frag- 

 ments such as usually occurs in the stomach, in 

 order that they may lie long enough in the intestine 

 to be tlioroughly dissolved. The stomach, therefore, 

 gives the dog opportunity to use a wider range of 

 substances for the satisfaction of its nutritive wants. 

 The transformation of x^roteids into urea occurs 

 more uniformly when the stomach is allowed to act. 

 — {Du Bois' archie, 1883, 89.) H. N. M. [797 



Influence of carbon-monoxide poisoning on 

 trypsin. — Podolrnski has found that the transfor- 

 mation of pancreatic trypsogen into trypsin is associ- 

 ated with th6 assumption of oxygen. Herzen finds 

 that the pancreatic infusion of dogs killed by carbon- 

 monoxide gas, which infusion, under normal circum- 

 stances, would have contained much trypsin, possesses 

 hardly any. He concludes that either the absence of 

 oxygen from the blood has led to a reconversion of 

 trypsin into trypsogen, or that trypsin forms with 

 carbon monoxide a compnund wlilch is not proteo- 

 lytic. — (PfliXg. archiv, xxx. 308.) ii. N. M. [798 



The physiological action of Heloderma poi- 

 son. — ■ That this lizard, the Gila monster (Heloderma 

 snspectum), is venomous, has been often asserted and 

 as often denied. AVeir Mitchell and Reichert find 

 that its mouth-liquids are liighly poisonous, Icilling 

 frogs, pigeons, and rabbits in a few minutes. This 

 establishes it as the only venomous lizard known. 

 What is of even more interest, perhaps, is the fact 

 that the physiological action of the poison is quite 

 different from that of snake-poison: the latter kills 

 essentially by paralyzing the respiratory centre, the 

 former by paralyzing the heart. Heloderma venom 

 causes no local injury when injected subcutaneously; 

 and arrests the heart in diastole, from which condition 

 the organ slowly passes into a contracted state. The 

 heart-muscle entirely loses its irritability when tlie 

 organ ceases to beat, and when other muscles and 

 the nerves still readily respond to stimulation. The 

 spinal cord is paralyzed. — (Medical news, Feb. 10.) 



H. N. M. [799 



Relations of the Mosasauridae. — M. Dollo, as- 

 sistant naturalist to the royal natural history museum 

 of Brussels, separates the Mosasauius Maximiliani of 

 Goldfuss generically fi-om the M. Camperi, under the 

 designation PterycoUasanrus. In this new genus 

 the pterygoids are united along two-thirds of their 

 entire length, especially in the dentary portion, 

 whereas in the typical Mosasaurus they are entirely 

 separate. This last is also the case with the Ameri- 

 can genera Tylosaurus, Lestosaurus, Holosaurus. In 

 another new genus now indicated, Plioplatecarpns 



(P. Marshii), whicli appears to be closely related to 

 Leiodon and Lestosaurus, and of which fragments 

 are contained in the museum of Brussels, the author 

 indicates the presence of a sacrum composed of two 

 united vertebrae having the same disposition as the 

 similar parts in the pelvic girdle in the iguana and 

 monitor. From the presence of this sacrum, M. Dollo 

 concludes, in opposition to the views of Prof. Cope 

 (who, under tire name of the Pythonomorpha, ap- 

 proximates these animals to the serpents), that the 

 mosasauroids were true lacertilians, and that they 

 held a place among these similar to that occupied by 

 the pinnipeds among the carnivora. — (Bull. mvs. 

 royal Belg., i. 55.) a. h. [800 



Mammals. 



The bunotherian mammals. — Professor E. D. 

 Cope defines the Bunotheria as resembling in most 

 technical characters the Edentata and the Kodentia. 

 Their enamel-covered teeth, however, separate them 

 •from the former, while the articulation of the lower 

 jaw is different from that found in the latter. This 

 is a transverse ginglymus with a posterior process in 

 the Bunotheria, as distinguished from the longitudi- 

 nal groove permitting antero-posterior motion of the 

 Rodentia. 



After dwelling on the characters of the related 

 forms, and pointing out the inconsistencies of the 

 present classification, he defined the five suborders 

 as follows : — 



I. Incisor teeth growing from persistent pulps. 

 Canines also growing from long persistent pulps, 



agreeing with external incisors in having molari- 

 form crowns I. Taeniodonta. 



Canines rudimental or wanting; hallux not opposa- 

 ble II. Tillodonta. 



Canines none; hallux opposable. 



III. Daubentonioidea. 



II. Incisors not growing from persistent pulps. 

 Superior true molars qnadrituberoulate ; hallux op- 

 posable IV. Prosimiae. 



Superior true molars qnadrituberoulate; hallux not 

 opposable V. Insect ivora. 



Superior true molars trituberculate; hallux not 

 opposable .....'... VI. Creodonta. 



It was possible that the group which he had called 

 the Mesodonta may yet be distinguished from the In- 

 sectivora by characters now unknown. But he could 

 not admit any affinity between this group and any 

 form of pachyderms, as suggested by Filhol, or of 

 Suillines as believed by Lyddeker, as such supposi- 

 tions are directly opposed to what we know of the 

 phylogeny of the mammalia. Tliese views are ap- 

 parently suggested by the bunodont type of teeth 

 found in various Mesodonta; but that character gives 

 little ground for systematic determination among 

 Eocene mammalia, and has deceived paleontologists 

 from the days of Cuvier to the present time. The 

 only connecting-point where there may be a doubt 

 as to the ungulate or unguiculate type of a mammal 

 is the family Periptyohidae of the suborder Condylar- 

 thra. The suborder Hyracoidea may furnish another 

 index of convergence. 



He had at one time called this order by the name 

 Insectivora, a course which some zoologists may pre- 

 fer. A name, liowever, should as nearly as possible 

 adhere to a group to which it was first applied, and 

 whose definition has become currently associated 

 with it. Such an application is a material aid to the 

 memory. There are various precedents for the adop- 

 tion of a new general term for a group composed of 

 subordinate divisions which have themselves already 

 received names. — [Acad, nat: sc. Pldlad. ; meetmn 

 April .3.) [801 



