56 



BULLETIN ()(), ITNTTKl) STATES NATIONAL MTTSEFM. 



scutal and lateral martrins arc straight and .subequal, meeting- at an 

 obtuse angle. The carinal margin is nearly straight. 



The carina is unusually shorty irregularly arched, having several 

 straightened faces in its dorsal contour. I'he roof is roundedi, passing 

 directly into the narrow sides, and marked Avith faint transverse, 

 arcuate growth-lines. The base extends triangularly between the 

 carinal latera. The apex is terminal and incurved, but not intruded 

 between the terga. It reaches only to the lower fourth of the carinal 

 margin of the terga. 



The upper latus is wedge-shaped. The scnital margin is straight and 

 about twice the length of the straight tergal margin. The carinal 



margin is slightly convex. The 

 umbo is terminal at the scuto- 

 tergal angle, which is a little less 

 than a right angle. 



There is no rostrum, but a lan- 

 ceolate space betw^een the rostral 

 laterfi is bridged with 3'ellowish 

 chitin. 



The rostral latus is quadran- 

 gular, at least twice as wide as 

 high. The basal margin is much 

 shorter than the scutal and par- 

 allel to it. The rostral margin 

 is concave, the lateral someAvhat 

 irregular. A Ioav diagonal riblet 

 divides the plate into triangular 

 areas. 



The inf ramedian latus is very 

 narrotV, sinuous, and as high as 

 the adjacent latera, its umbo at 

 the acute apex. It is appar- 

 ently concrescent or partially so, 

 with the carinal latera, the suture between them being very incon- 

 spicuous. 



The carinal latus is triangular, higher than wide, the apex curA'^ed 

 toAvard the inf ramedian latus. The tAvo latera almost meet at the base 

 beloAV the carina. 



The peduncle is coA^ered Avith wide imbricating scales in six very 

 distinct rows of about fifteen scales each. The scales of adjacent rows 

 interlock only shortly. 



Length of the capitulum 8, breadth 3.7 mm. Length of the pedun- 

 cle 3.7 mm. Length of the carina 5.2, diameter near base 1.2 mm. 



This peculiar little species resembles S. halanoldes in the short 

 carina and triangular upper latus, but the carinal latus is short, and 



Fig. 20.— Scalpellum pentacrinarum x 6, with 

 6, dorsal and c, ventral details. 



