Plate, figure 1 showing cranium, blow-hole, and sacs of the porpoise by [Francis Sibson?] Figure 1 showing the cranium, part of the blow-hole or nasal canal, and the sacs of the porpoise. Also includes two unpublished illustrations showing further views of this part of the porpoise's anatomy. Subject: Zoology Published in Philosophical Transactions as 'On the blow-hole of the porpoise'. Communicated by Thomas Bell. Received by the Royal Society on 18 December 1845. Read 12 March 1846. [1845]