DESCRIPTION OF SPECIES ANTHOZOA 271 



The dimensions of a large individual are: Length along the convex 

 side, 19 millimeters; diameter at the rim of the calyx, 3 millimeters. 



Remarks. — This species may be distinguished from C. arcuata, with 

 which it is associated, by its smaller size, its more slender form, its less 

 number of septa, and often by its less curvature. In individuals of the 

 two species of equal length the maximum diameter of C. arcuata is twice 

 that of C. minor. In their surface markings the two species are essen- 

 tially alike. The species is most closely allied to C. tantilla (S. A. M.), 

 but it is usually more curved and has less strong longitudinal costse. 



AMPLEXUS RUGOSUS n. sp. 

 Plate 10, figures 22-25 



Description. — Corallum simple, rather small, usually enlarging more 

 or less abruptly at first and then less rapidly, nearly straight, moderately 

 or rather strongly curved, or frequently geniculate, marked by many 

 strong, exceedingly irregular annular wrinkles. Septa 18 to 21 in num- 

 ber, rather thick, extending nearly to the center 'of the corallum; tabulas 

 and dissepiments strongly developed, the lower portion of some indi- 

 viduals being so filled with calcareous matter as to be essentially solid. 



The dimensions of an average individual are : Length, 28 millimeters ; 

 greatest diameter, 8 millimeters. 



Remarks. — This species resembles A. corniculum S. A. M., from the 

 Chouteau limestone at Sedalia, Missouri, but the septa are thicker and 

 less numerous and extend more nearly to the center of the corallum. 



AMPLEXUS BREVIS n. sp. 

 Plate 10, figures 26-29 



Description. — Corallum rather small, curved, short, pointed below and 

 expanding rapidly upward ; marked by numerous strong, irregular, an- 

 nular wrinkles. Calyx shallow, septa thick, 20 to 22 in number, not all 

 of which reach the center of the corallum, some of them often curved. 

 Tabula? well developed in the upper portion of the corallum, the lower 

 portion solidified by reason of the abundant secretion of calcareous 

 matter. 



The dimensions of an average individual are: Length along convex 

 side, 24 millimeters; diameter at margin of calyx, 14 millimeters. 



Remarks. — This species is not an entirely typical member of the genus 

 Amplexus, because of its short and rapidly expanding form. In its 

 rough, annular markings it resembles A. rugosa of this paper, but it dif- 

 fers from that species in its much shorter corallum. 



