BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 18. AFD. IV. N:0 1. 67 



epipliysis and tlie rotula fig. 91, 92, both arcuated below, 

 elongated, equal, very low, tliin, the upper margin of the ro- 

 tula expanded internally, the lower margin tumid externally. 

 The ventral surfaee of the pyramid, fig. 88, is like that of the 

 Eneope, level in the interno-external direction, the tnberosity 

 of the external angle slightly bipartite, the labial process 

 broad. The lateral surfaces of the pyramid, fig. 80, 89, 90, 

 o väte, largely emarginate for the epiphysis. The rachis 

 with its series of holes divides it diagonally in two unequal 

 areas, the upper one conspicuously the larger. The curves of 

 accretion are dense and distinct. The radiating series of per- 

 forations, to a great part conspicuous in the lower area, are 

 few and scattered in the upper. The triangulär area, tr., is 

 ver}^ broad at its excavated base under the epiphysis; it di- 

 vides the upper area in two nearly equal halves, the inner 

 wing being the other half; it is smooth, marked with incur- 

 vated lines of accretion parallel to the emargination. AVhen 

 the intermuscular sheet is removed, the tr. presents through- 

 out a succession of irregularly disposed partitions and large 

 lacunes, partly opened, fig. 89, 90. The radiating lameliar 

 partitions of the external wing are regular, those of the in- 

 ternal less so, interlacing, dendritic. The auricles, fig. 93, 

 like those of Eneope, arise from the interradium and are united 

 into one single piece for each tooth, flattened, slightly lobate. 

 Along its margins the two retractors are attached, whicli 

 are undivided and have tlieir insertions in two comma-shaped 

 deep inpressions near the labial process. The slender protrac- 

 tors, attached between tliem, but lower down, fig. 93, are in- 

 serted at the base of the marginal tnberosity, fig. 88. Five 

 pairs of muscles, that, without doubt, exist in all, were first 

 observed in tliis species, m. phar., fig. 86. One of each pair 

 is attached to either side of the labial process, and inserted 

 on the pharynx. Their action must be to expand it. The 

 two »linecB eminentes» of the dental slide, PI. X, fig. 735, 137, 

 are contiguous, linear, placed at less than a right angle to 

 each other. The teeth are long, high, compressed, the 5 the 

 largest, then the 1 and 4, the 2 and 3 being smaller. They 

 are slightly curved inward. Their back, of a triangulär section, 

 fig. 138, expanded and wedge-shaped at the crown, fig. 151, is 

 rec^eived into the corresponding furrow of the slide, fig. 135, 136^ 

 the roughened area for the fibrous tissue being linear. fig. 137. 



