BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 18. AFD. l\. X:0 1. (il) 



attachecl. They have tlieir iiisertions in two jDairs of liiiear, 

 walled impressions, one on eitlier sicle of tlie basilar ridge, 

 flfj. 'J6, 97. Near tlie top of the auricle are attached tlie 

 two slender protractors, inserted in a line witli them, near 

 the lacunes. The teeth, Pl. IX, fuj. 94, Pl. X, fig. 139, Pl. 

 XI, fig. 152, unlike those of the preceding, low, thick, slightly 

 curved ontward, like those of Clypeaster or Echinocyanius, 

 the 5 much the larger, then the 2 and o, the 1 and 4 l)eing 

 smaller. The back, expanded and wedge-like at the erown, is 

 of a triangulär section and received in the deeply triangulär 

 dental slide. The prismal part is very low and broad. of a nearh^ 

 rectangular section. 



In the Echinocyanius angulosus Leske, Pl. IX, fig. 102 

 -109, Pl. XI, fig. Ml, 145, the dental system is high, pul- 

 vinate, pentagonal, the 5 broad, transverse, the III a little pro- 

 duced. The sides are symmetrically and bilaterally unequal, 

 the 5 being to the 2 and 3 as 1 to Ö,::. and to the 1 and 4, 

 as to 0,7 0. The 5, fig. 105, 141, is transverse, broacler than 

 it is long, the 4, fig. 104, much narrower, but e(|ual in height, 

 the &-side larger. The alveolar ambitus is conformable, pen- 

 tagonal, the I and V slightly produced l^eyond its corners. 

 The dental slide is raised, reclining at an angle of nearly 50°, 

 slightly concave. The symphysis is Innate, convex, but not 

 bulging exteriorly. The pyramid 4, fig. 103, seen from above, 

 is arrow-shaped, the crests strong, the siipra-alveolar process 

 large and prominent, fig. 102, 104, 105, 106. The epiphysis 

 and rotula, fig. 103, 108, are simple laminfe. The inner wings 

 are convergent, not lamellated, fig. 141. the dental slide deep. 

 The inferior surface is as in Laganum, convex, strongly arched, 

 the middle compact part narrow, the sides much expanded, 

 rounded, rising, not lamellated, but the reticular texture evi- 

 dently radiating, fig. 104 x , 105, 107 x , 141; they are sepa- 

 rated from the crest + not by a lacune, but only by an oval 

 transverse impression. The 1 and 4, and 2 and 3 are ineqni- 

 lateral, as in Laganum. The labial process is broad, projec- 

 ting. The lateral surfaces, the inter-muscular sheets, fig. 102, 

 are obovate in the direction of the tr., truncated above for the 

 epiphysis, with distinct curves of accretion, but no radiating 

 ridges and no perf orations. The triangulär area, tr., is broad 

 above, for the large supra-alveolar process, anrl compact. 

 The outer wing is broadly lunate, the inner short. The au- 



