44 THECOPSAMMIA. 



Thecopsammia socialis Podrt. 



Thecopsammia socialis Povrt. Bull. Mus Comp. Zool., No. 7. 

 Plate II., figs. 9 and 10. 



Corallum turbinate, rather long conical, Avith a thick, not much 

 constricted peduncle. Wall and epitheca as in preceding species, 

 but obscure traces of costae can sometimes be seen through the 

 epitheca near the peduncle. Calicle elliptical, moderately deep. 

 Septa entire, smooth, crowded, not exsert, thick near the wall. Six- 

 unequal systems and five cycles. The convergence of the septa <if 

 the fourth cycle to meet in front of the tertiaries generally plainly 

 visible from outside. The septa of the fifth cycle are developed in old 

 specimens only, and then in few of the systems; but they soon become 

 very large and encircle the two preceding cycles. The tertiaries re- 

 main smallest of all. The columella is papillose and porous, but more 

 compact than in the preceding species, and nearly always forms three 

 distinct masses, of which the middle one is largest. 



This species often forms clusters, several individuals being united by 

 their bases. 



Height about 2 cm., diameter of calicle about 13 mm. 



Off Coffin's Patches, in 195 fathoms. 



Off Sombrero Lighthouse, in 262 fathoms. 



This species, according to Dr. Duncan, has also been found by the 

 "Porcupine" Expedition, in 345 and 363 fathoms, in the seas north of 

 Scotland. The specimens were more developed than those from 

 Florida, and rather variable, since Dr. Duncan distinguished three 

 varieties. There is a considerable range of variation also in the 

 Florida specimens. I have found in some cases, since the iirst descrip- 

 tion was written, the traces of costae which had been noticed in some 

 of the European specimens. The epitheca is particularly subject to 

 variation, sometimes extending to the edge of the calicle, sometimes 

 confined to the lowest parts of the peduncle. A specimen of the 

 latter category shows distinct granular costae in the bare part of the 

 peduncle. 



