416 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



Order ACTINIARIA 



Family HALCAMPOIDIDAE 



CALAMACTIS, new genus 



Elongate Halcampoididae with well-developed physa. Column 

 smooth, not divided into regions. No sphincter. Tentacles few, 

 rather short, A single siphonoglyph fairly well developed. All 12 

 pairs of mesenteries perfect and filamentous, the first cycle of 

 mesenteries fertile, the second sterile. Retractors very strong, 

 reniform. The same number of mesenteries proximally and dis- 

 tally. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors. 



CALAMACTIS PRAELONGUS, new species 



Figure 78, a, b 



Tentacles 24. Retractors of the mesenteries of the second cycle 

 weaker than those of the first but of same appearance. Basitrichs 

 of the column 14-17 by 2.8-3 ix; those of the tentacles 18.3-21 by 

 8-3.5 /x; those of the actinopharjmx 19-26.2 by 2.8-4 ix; those of 

 the filaments partly 10.6-12 by about 2.2 /x, partly 24-31 by 5-5.6 /x, 

 the latter broad in their basal end. Microbasic p-mastigophors of 

 the actinopharynx 17-24 by 4.2-5 /n; those of the filaments 18.3- 

 25 by 4.2-5 fx. 



Measurements. — Length 7 cm. in contracted and very deformed 

 condition. 



Holotype. — U.S.N.M. No. 49453, Estero de la Luna, Sonora, 

 Mexico, April 10, 1940. 



Remarks. — The single specimen is strongly contracted, de- 

 formed, and turned inside out. Figure 78, a, shows the appearance 

 of a retractor; 78, h, of a parietal muscle of the first cycle. 



Family ANDVAKIIDAE 



ANDVAKIA INSIGNIS, new species 



Figure 78, c, d 



Column divisible into physa, scapus, and scapulus. Scapus with 

 tenaculi incrusted with grains of lime-sand and foraminifers. The 

 sphincter is mesogloeal, very long but weak, stronger in its upper- 

 most and lowermost parts, between which consisting of a single 

 row of meshes, wholly separated from the endodermal muscles of 

 the column and situated either in the middle of the column or 

 nearer the ectoderm. Tentacles about 24, short, their longitudinal 

 muscles ectodermal. Siphonoglyphs indistinct. Six perfect and 

 fertile pairs of mesenteries and five pairs of imperfect ones; on 

 the one side of a directive mesentery a pair of the second cycle is 



