30 PBOCEEDINGS OP THE NATIOlirAL. MUSEUM vol.72 



lacunae; they bear two or three very salient lumen pores which give 

 the froatal a spinous aspect. The frontal is terminated distally by 

 a wide, smooth convex mucro; it forms with the wide apertural arch 

 a kind of broad oblique peristome surrounding a kind of spiramen; 

 the latter is itself protected in front by a small more or less salient 

 tongue. The aperture is buried by the characteristic arch; the peri- 

 stome is thin and bears on each side of the aperture a large, short, 

 hollow spine, and distally two broad, claviform, bifid spines, often 

 joined together to form a small special tongue. 



,, , ry . /X2 = 0.45-0.50 mm. 



Measurements. — Zooeciai, ^ ^^ ^ „^ 



1*2 = 0.25-0,30 mm. 



Structure. — This species is quite original and well characterized by 

 its spinous costules. The apertural arch is very constant; the spira- 

 men could correspond to a special function like that of the Galeop- 

 sidae and indispensable to the zooecial life. 



The lacunae are so small that they must be subject to the phe- 

 nomena of capillarity, of which it will be necessary to make a special 

 study. 



The apertural arch is altogether distinct from what we have 

 observed in Crihrilina lineata and which is formed by the junction of 

 two wide oral spines. Here it forms an integral part of the oral 

 mucro and constitutes with it a true special armature in which the 

 spiramen is perforated. 



The arrangement of the costules is totally different from that of 

 the genotype, GepJiyrotes nitido-pundata Smitt, 1868. Their struc- 

 ture is that of Acanthocella. 



The two large lateral spines observed on each side of the aperture 

 are perhaps in reality very small pedunculato avicularia correspond- 

 ing to the oral avicularia noted in almost all the species of the genus. 

 Our rare specimens did not bear a single ovicell. 



Occurrence. — Albatross Station D. 2319, north of Cuba; 23° 10' 

 37'' N.; 82° 20' 06" W.; 143 fms.; gray coral. 

 Albatross Station D. 2639, Straits of Florida; 25° 04' 

 50" N.; 80° 15' 10" W.; 56 fms.; coral sand. 



Holotijpe.—C&t. No. 7508, U.S.N.M. 



Genus MARSSONOPORA Lang, 1914 



MARSSONOPORA UNCIFERA, new species 



Plate 3, Figures 1, 2 



Description. — The zoarium encrusts shells. The zooecia are ar- 

 ranged in linear series; they are oval, elongated, and united with 

 each other by filiform zooeciules with very small orifice and arranged 

 in the form of stolons. The opesium is oval; the mural rim is thin 

 and bears a dozen spines in the form of claivs. The ovicell is hyper- 

 stomial, globular, salient, always closed by the operculum. 



