Tins investigation was carried out to determine rite trichlorethylene concentrations delivered by a standard anaesthetic apparatus, and to assess the alteration of these concentrations with changes in (a) 'valve opening, (b) rate of gaseous flow, (c) fluid volume, and (d) liquid temperature. METHODA standard Airmed anaesthetic machine with a MaEett head was used. The valve openings on the head of the trichlorethylene bottle were graded as 1, 2, 8 and 4 (marked F~LL). The trichlorethylene vapour, carried by nitrous oxide, passed through a 86-inch pmce of rubber tubing co attain room temperature. A half-litre glass weighing bottle, with valves at its inlet and outlet, could be attached. By experiment, it was found that at a flow rate of five htres or greater, for a period of one minute, complete displacement, for practical purposes, occurred.The valve opening, volume of trichlorethylene, and the gaseous flow rate were pre-arranged for each experiment. The gas was allowed to flow continuously for 90 minutes. At each fifteen-minute interval, a sample was taken, and the trichlorethylene temperature and volume with the room temperature and atmospheric pressure were recorded.The sample was collected by connecting the weighing bottle and tubing for one minute. The bottle was then wexghed, flushed with mtrous oxide for one minute, and re-weighed. From the change in weight, the tnch]orethylene vapour concentration coulc be calculated using the following formula: l~st~Ts The first group of experiments was camed out to determine the effect of altering the gaseous rate of flow. With the mltml volume constant (90 cc ), the

The taxonomic validity of the holotype and sole specimen of the pachycephalosaurid Gravitholus albertae (TMP 1972.027.0001) from the Belly River Group (Alberta, Canada), remains unresolved forty years after its first description. The diagnosis for this species is tenuous at best and extensive cranial fusion has prevented a thorough description and taxonomic referral of TMP 1972.027.0001. We used synchrotron µCT imaging to identify fused sutures and segment the individual elements that comprise TMP 1972.027.0001. This allowed for a detailed description of the specimen in a more thorough comparative framework with other known pachycephalosaurid specimens. Using new observations of contacts between cranial elements, the morphological distinction of TMP 1972.027.0001 from other Belly River Group pachycephalosaurids was tested with bivariate and multivariate morphometric analyses. TMP 1972.027.0001 is morphologically consistent as an end-stage semaphorant of Stegoceras validum. Furthermore, we find no taxonomically significant morphometric distinctions between Gravitholus albertae, Hanssuesia sternbergi, and Stegoceras validum, and propose the former two are synonymous with the later. Large Stegoceras validum frontoparietals show statistically significant dimorphism in the thickness of the frontonasal boss, which is not apparent amongst juvenile and subadult specimens. Pathologies consistent with intraspecific combat (“headbutting”) appear restricted to frontoparietal domes with proportionally taller frontonasal bosses, and suggests that the two morphs represent sexual dimorphs, rather than separate species. Foraminacephale brevis and Stegoceras validum are the only named pachycephalosaurids recognised in the Dinosaur Park Formation. The stratigraphic and temporal range of Stegoceras validum is extended into the underlying Oldman Formation. Pachycephalosaurid diversity in the Campanian is reduced as a result of these revised taxonomic hypotheses. A revised phylogenetic character matrix, recognising taxonomic synonymies and ontogenetically dependent character states results in a largely unresolved Pachycephalosauria.

A new method has been described for measuring fibrinolytic activity. The method is based on the change in turbidity resulting from the dissolution of suspended particles of fibrin under the influence of fibrinolytic agents. Because the technic exposes a vast surface area of substrate, measurable changes occur rapidly. The procedure is not complex, yet provides more accurate estimates than other methods employing fibrin as a substrate. The method also has the advantage that conditions such as temperature, pH and length of incubation can be varied. Experiments illustrating this have been reported. The following two fibrinolytic agents were studied. 1. Human plasmin activated with glycerin. 2. An extract of Aspergillus oryzae.