692 MR FKANK J. COLE 



7. M. ethmoideo-nasalis. (Figs. 3, 11, e.n.) 



J. Muller, Compressor narium (p. 259). 



A very small cylindrical muscle, with its fibres somewhat twisted like a rope in one 

 dissection (cp. fig. 3). Its origin, as seen by dissections, is indefinite. Many, if not 

 most, of the fibres arose from the ventral convex protuberance at the anterior extremity 

 of the subnasal bar (cp. Part I., fig. 1). A number of fibres, however, appear to be 

 contributed by the transversus oris, of which the present muscle may conceivably be a 

 differentiated portion. It passed vertically upwards in a curve, bent externally round 

 the origin of the second tentacle (J. Muller, by mistake, says the first), and is inserted, 

 after a very short course, partly into the first nasal ring above the ventral anterior 

 process, and partly into the lateral wall of the nasal tube between rings one and two, 

 whilst the most posterior fibres intermingled with the insertion of the nasalis, as 

 mentioned under that muscle. 



In the sections the following conditions are found. The posterior fibres arise from 

 about the dorsal third of the fascia between the opposed surfaces of the transversus 

 oris and the tentaculo-ethmoidalis. These fibres are tightly wedged in between the 

 two latter muscles, but a very careful examination failed to convince me that there is 

 any mingling of the fibres of the three muscles. The posterior fibres of the ethmoideo- 

 nasalis pass almost straight upwards, but slightly forwards, and are inserted into the 

 dorsal-lateral wall of the nasal tube in front of the second nasal ring. These are the 

 fibres that are confused at their insertion with the anterior extremity of the insertion 

 of the nasalis (q-v.). As the tentaculo-ethmoidalis dies away in front, the ventral end 

 of the ethmoideo-nasalis bends sharply inwards, almost at a right angle, under the dorsal 

 pseudo-commissure of the transversus oris, to take its origin from the dorso-lateral 

 margin of the zone of soft cartilage at the anterior extremity of the subnasal bar, 

 just at the fusion with the transverse labial and between the origin of the tentaculo- 

 ethmoidalis (below) and the " insertion " of the pseudo-commissure (above). On the 

 right side the origin extended further forwards on to the external margin of the 

 transverse labial. In front, the insertion leaves the dorso-lateral wall of the nasal tube 

 and passes on to the dorsal margin of the first nasal ring at the point where this fuses 

 with the forwardly-directed lateral process (cp. Part I., fig. 1). The insertion finally 

 passes forwards as a definite narrowing bundle over the external surface of the first 

 nasal ring on the ventral margin of the same, into which it is inserted right up to its 

 anterior extremity, lying just below the first ring at this part of its course. 



The contraction of the two ethmoideo-nasalis muscles is stated by P. Furbringer to 

 press the first ( = my second) tentacles against the nasal tube, and thus close the nasal 

 opening ; but J. Muller asserts, and with more probability, that it presses the anterior 

 end of the nasal tube against the subnasal bar, and closes the nasal opening in that way. 

 Moreover, in my sections the muscles arise so far back that the second tentacles could 

 not possibly be affected in the way Furbringer supposes. 



